COMMUNICATION PLATFORM PAYLOAD

DEFINITION STUDY FINAL REPORT

NASA CR174929

WDL-TR10632

MARCH 1986

Volume II - Technical Report

NASA

NASA LEWIS RESEARCH CENTER

CONTRACT NO.: NAS3-24235

N86-2740 4

T r

JNASA-CR-174929 ) COMMUNICATIO N PIAIFORM

*AYLOAD DEFINITIO N fCffD ) S1UIY. VOLUME 2:

TfCHNICA I EEPOB1 Final Bepcrt, Jun. 1984 -

Jul. 1985 (Ford Aerospace and Communications Unclas

Ccrp.J 598 p HC A25/WP A01 CSCL 22B G3/18 43256

&

Communications Corporation
1. Report No.

CR174929

2. Oov«mm»ot Acueealon No. 3. Recipient's Catalog No.

WDL TR-10632

4. Title and Subtitle

Coiranunicatio 11 • " ' n Platform Payload Derinitlon(CPPD) Study

Final Report Volume n Technical Report

5. Rapon Date

March 1986

6. Performing Organization Code

7. Authors)

E. M. Hunter, T. Driggers, R. Jorasch

6. Performing Organization Report No.

10. Work Unit No.

9. Performing Organization Name and Address

Ford Aerospace & Communications Corporation

3939 Fabian Way

Palo Alto, California 94303

11. Contract or Grant No.

NAS3-24235

12. Sponsoring Agency Name and Address

NASA Lewis Research Center

21000 Brookpark Road

Cleveland, Ohio 44135

13. Type of Report and Period Covered

FLnal

June 1981 - July 1985

14. Sponsoring Agency Code

15. Suftnlflmentary Notes •,,.-,-,* . ^ -,

NASA Contract Manager: William A. Poley

Two other Volumes were also prepared: Volume I, Executive Summary, Volume III

Addendum

16. A>v>trar.l

This is the Ford Aerospace & Communications Corporation Final Report for the

Communication Platform Payload Definition (CPPD) Study program conducted for

NASA Lewis Research Center under contract No. NAS3-24235.

This report presents the results of the study effort leading to five potential

platform payloads to service CONUS and WARC Region 2 traffic demand as projected

to the year 2008. The report addresses establishing the data bases, developing

service aggregation scenarios, selecting and developing' 5 payload concepts,

performing detailed definition of the 5 payloads, costing them, identifying

critical technology, and finally comparing the payloads with each other and

also with non-aggregated equivalent services.

17. Key Words (Suggested By Authorts))

Communications Platform

Geostationary Platform

Satellite Communications

Telecommunication Forecast

Fixed Satellite Services

19. Security Claaalf. (of this report)

Unclassified

20. Security CloMlt. (ot this page)

Unclassified

21. No. ot page* i-rtce'

'For sale by the National Technical Information Service. Springfield. Virginia 22161
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Communications Corporation

TABLE OF CONTENTS

Page

1.0 OVERVIEW 1-1

1.1 NASA STUDY CONTRACT . 1-1

1.2 STUDY OBJECTIVES 1-1

1.3 GUIDELINES AND CONSTRAINTS 1-2

1.4 STUDY APPROACH 1-4

1.5 SUMMARY DESCRIPTION 1-5

1.6 ORGANIZATION OF FINAL REPORT 1-8

2.0 DATA BASE (TASK 1) - 2-1

2.1 OVERVIEW 2-1

2.2 TRAFFIC FORECASTS 2-3

2.2.1 Introduction and .Summary of Traffic Demand vs Supply 2-3

2.2.2 U.S. Domestic Traffic Forecast -2-17

2.2.3 Non U. S. Domestic Traffic Forecast 2-21

'2.2.4 Regional Services Traffic Forecast 2-27

2.2.5 International Traffic Forecast 2-31

2.2.6 Maritime Services Traffic Forecast 2-34

2.2.7 Future Growth for Traffic Forecast to Year 2008 2-35

2.3 TRAFFIC DISTRIBUTION MODELS 2-36

2.3.1 Approach 2-36

2.3.2 NASA FSS Model 2-38

2.3.3 Intelsat FSS Model 2-38

2.3.4 Other Distribution Models 2-39
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TABLE OF CONTENTS (Cont.)

Pace

2.4 SPACE AND TERRESTRIAL SUPPLY FORECAST 2-43

2.4.1 Overview 2-43

2.4.2 Estimate of Satellite Transponder Supply 2-47

2.4.3 Terrestrial Terminal Supply 2-50

2.5 CONSTRAINTS. SELECTION CRITERIA. AND OTHER 2-60

CONSIDERATIONS

2.5.1 Study and Task Constraints 2-60

2.5.2 Service Aggregation Scenario Selection Criteria 2-61

2.5.3 Payload Concept Evaluation Criteria 2-63

2.5.4 Other Consideration 2-63

3.0 AGGREGATION SCENARIO DEVELOPMENT (TASK 2) 3-1

3.1 OVERVIEW 3-1

3.1.1 Rationale used in Scenario Development 3-2

3.1.2 Adaptation of Traffic Models 3-7

3.1.3 Terrestrial System Characteristics 3-9

3.1.4 Orbit Allocations 3-9

3.2 DESCRIPTION OF EIGHT CANDIDATE SCENARIOS 3-12

3.3 REQUIREMENTS COMPLIANCE MATRIX AND RANKING 3-22

3.3.1 Criteria for Evaluation 3-22

3.3.2 Launch Concept Compliance 3-23

3.3.3 Evaluation Ranking 3-23

3.4 CONCLUSIONS 3-26

4.0 PAYLOAD CONCEPT DEVELOPMENT (TASK 3) 4-1

4.1 OVERVIEW 4-1
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TABLE OF CONTENTS (Cont.)

Page

4.2 APPROACH 4-3

4.2.1 Background - 4-3

4.2.2 Space/Ground System Trades and Concept Ranking 4-25

4.2.3 Traffic Loading Analyses 4-26

4.3 SCENARIO II PAYLOAD CONCEPT DEVELOPMENT 4-42

4.3.1 General Description 4-42

4.3.2 Institutional and Regulatory Issues 4-42

4.3.3 Summary Antenna Coverages 4-46

4.3.4 Transponder Configurations 4-51

4.3.5 Traffic Loading 4-60

4.3.6 Terrestrial System Characteristics 4-64

4.4 SCENARIO IV PAYLOAD CONCEPT DEVELOPMENT 4-65

4.4.1 General Description 4-65

4.4.2 Institutional and Regulatory Issues - 4-65

4.4.3 Summary Antenna Coverages 4-69

4.4.4 Transponder Configuration 4-69

4.4.5 Traffic-Loading 4-74

4.4.6 Terrestrial System Characteristics 4-74

«

4.5 SCENARIO V PAYLOAD CONCEPT DEVELOPMENT 4-75

4.5.1 General Description 4-75

4.5.2 Institutional and Regulatory Issues 4-75

4.5.3 Summary Antenna coverages 4-78

4.5.4 Transponder Configuration 4-80

4.5.5 Traffic Loading 4-84

4.5.6 Terrestrial System Characteristics 4-86

4.6 SCENARIO VI-A PAYLOAD CONCEPT DEVELOPMENT 4-87

4.6.1 General Description 4-87

4.6.2 Institutional and Regulatory Issues 4-91

4.6.3 Summary Antenna Coverages 4-93
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TABLE OF CONTENTS (Cont.)

Page

4.6.4 Transponder Configuration 4-95

4.6.5 Traffic Loading 4-99

4.6.6 Terrestrial System Characteristics 4-104

4.7 SCENARIO VI-B PAYLOAD CONCEPT DEVELOPMENT 4-105

4.7.1 General Description 4-105

4.7.2 Institutional and Regulatory Issues • 4-105

4.7.3 Summary Antenna Coverages 4-105

4.7.4 Transponder Configuration 4-110

4.7.5 Traffic Loading 4-116

4.7.6 Terrestrial System Characteristics 4-117

4.8 CONCLUSIONS AND RANKING OF SCENARIOS 4-118

4.8.1 Conclusions .4-118

4.8.2 Bandwidth and Reuse 4-118

4.8.3 Modulation Efficiency 4-119

4.8.4 Throughput 4-119

4.8.5 Utilization 4-122

4.8.6 Digital/Analog Tradeoffs 4-124

4.8.7 Qualitative Issues 4-126

4.8.8 Ranking 4-131

5.0 PAYLOAD DEFINITION (TASK 4) 5-1

5.1 OVERVIEW 5-1

5.1.1 Scope of Payload Definition 5-1

5.1.2 Weight and Power for All Scenarios 5-2

5.1.3 Weight and Power of Payloads used in Scenarios 5-4

5.1.4 Approach to Payload Definition Development 5-5
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TABLE OF CONTENTS (Cont.)

Page

5.2 SCENARIO II DEFINITION 5-14

5.2.1 Introduction 5-14

5.2.2 C-Band FSS Payload 5-20

5.2.3 Ka-Band FSS Pavload 5-42

5.2.4 Ka-Band Scan Payload 5-58

5.2.5 Ku-Band FSS Payload 5-74

5.2.6 Ku-Band DBS Pavload 5-91

5.3 SCENARIO IV DEFINITION 5-106

5.3.1 Introduction 5-106

5.3.2 Ku-Band FSS Pavload 5-111

5.3.3 Ku-Band DBS Payload 5-125

5.4 SCENARIO V DEFINITION 5-138

5.4.1 Introduction 5-138

5.4.2 C-Band FSS Payload -5-142

5.4.3 Ka-Band FSS Pavload 5-157

5.4.4 Ka-Band Scan Payload 5-157

5.4.5 Ku-Band FSS Pavload 5-157

5.5 SCENARIO VI-A DEFINITION . 5-181

5.5.1 Introduction 5-181

5.5.2 C-Band FSS Payload 5-188

5.5.3 C/L Band Maritime Payload - Western Atlantic 5-188

5.5.4 C-Band FSS International Payload 5-205

5.5.5 Ka-Band FSS Payload 5-230

5.5.6 Ka-Band Scan Payload 5-230

5.5.7 Ku-Band FSS Payload 5-230

5.5.8 60 GHz Inter-Satellite Link 5-230

5.6 SCENARIO VI-B DEFINITION 5-234

5.6.1 Introduction 5-234

5.6.2 C/L Band Maritime Payload - Eastern Pacific 5-240
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TABLE OF CONTENTS (Cont.)

5.6.3 C-Band Non-CONUS FSS Pavload

5.6.4 Ku-Band Non-CONUS FSS Payload

5.6.5 Ka-Band FSS Payload

5.6.6 Ka-Band Scan Payload

5.6.7 Ku-Band FSS Payload

5.6.8 60 Ghz Inter-Satellite Link

Page

5-243

5-266

5-277

5-277

5-277

5-278

6.0 PAYLOAD COSTING (TASK 5) 6-1

6.1 OVERVIEW 6-1

6.2 COST FORECASTING METHODOLOGY

6.2.1 Approach

6.2.2 PRICE Cost Model

6-1

6-1

6-2

6.3 PAYLOAD COST DETAILS

6.3.1 Summary

6.3.2 Payload Cost Sheets

6-5

6-5

6-5

6.4 SCENARIO PAYLOAD COST 6-40

6.5 SCENARIO PLATFORM COST 6-40

7.0 CRITICAL TECHNOLOGY 7-1

7.1 OVERVIEW 7-1

7.2 ANTENNA TECHNOLOGY

7.2.1 Background

7.2.2 Limitations Imposed on Communications Satellite

Antennas

7-1

7-1

7-3
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TABLE OF CONTENTS (Cont.)

Page

7.2.3 Communication Satellite Antenna Technology in 1998 7-5

7.2.4 Summary of Antenna Technology 7-20

7.3 RF TRANSPONDER TECHNOLOGY 7-23

7.3.1 Background 7-23

7.3.2 Power Amplifier 7-24

7.3.3 Power Combining Technigues 7-27

7.3.4 Receiver Technology 7-29

7.4 ON-BOARD PROCESSING TECHNOLOGY 7-31

7.5 PAYLOAD ON-ORBIT SERVICING TECHNOLOGY 7-35

7.6 GROUND TERMINAL TECHNOLOGY 7-38

7.6.1 Terminal Antenna Development 7-39

7.6.2 RF Subsystem Development 7-40

7.6.3 Digital Eguipment Development 7-41

7.6.4 User Interface Development 7-42

7.7 FREQUENCY RE-USE 7-43

7.8 IDENTIFICATION OF KEY TECHNOLOGY DRIVERS 7-44

7.8.1 Overall Technology 7-44

7.8.2 Component Technology 7-48

7.8.3 Support Technology 7-52

8.0 SYSTEM COMPARISONS (TASK 7) .8- 1

8.1 OVERVIEW 8-1

8.2 PHYSICAL PARAMETER COMPARISON 8-2

8.2.1 Weight and Power for All Scenarios 8-2

8.2.2 Weight and Power of Payloads used in Scenarios 8-3
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TABLE OF CONTENTS (Cont.)

Page

8.3 SPECTRUM/ORBIT UTILIZATION 8-4

8.3.1 Bandwidth and Reuse 8-7

8.3.2 Modulation Efficiency 8-8

8.3.3 Throughput Comparison 8-8

8.3.4 Utilization Factor Comparison 8-9

8.4 COST COMPARISONS 8-9

8.4.1 Pavload Costs 8-9

8.4.2 Space Segment Costs 8-10

8.4.3 Transponder Cost per Year Comparison 8-14

8.4.4 Alternative Approach Cost Comparison 8-15

8.5 GROUND SEGMENT IMPACT 8-17

8.5.1 Ground Segment Cost Estimates 8-17

8.5.2 Ground Segment Cost Comparison 8-18

8.6 OVERALL RANKING OF SCENARIOS 8-20

8.7 ASSESSMENT OF PROBABILITY OF IMPLEMENTATION 8-22

9.0 SUMMARY/RECOMMENDATIONS 9-1

9.1 OBJECTIVES ACCOMPLISHED 9-1

9.2 ANSWERS TO STUDY QUESTIONS 9-2

9.3 RECOMMENDED FUTURE ACTIONS 9-3

REFERENCES R-l
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SECTION INDEX

Page

1.0 OVERVIEW 1-1

1.1 NASA STUDY CONTRACT 1-1

1.2 STUDY OBJECTIVES 1-1

1.3 GUIDELINES AND CONSTRAINTS 1-2

1.4 STUDY APPROACH 1-4

1.5 SUMMARY DESCRIPTION 1-5

1.6 ORGANIZATION OF FINAL REPORT 1-8
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1.0 OVERVIEW

1.1 NASA STUDY CONTRACT

This Volume II. Final Technical Report, presents the composite results of the "Communications Platform Payload Definition

Study" performed under the NASA-Lewis Research Center contract

with Ford Aerospace & Communications Corporation. NAS3-24235.

The overall study period of performance was June 1984 though July

1985.

This study was accomplished as a joint effort of Ford

Aerospace and Satellite Systems Engineering (SSE). SSE provided

the satellite user expertise in the service aggregation scenarios

and also provided evaluation and adaptation of the traffic models

for the various services. The SSE user interpretation was based

upon experience in supporting DBSC's planned domestic DBS service

as well as in dealing with a number of domestic band

international users in defining the communications needs and

economic viability of satellite communication.

The Ford Aerospace Study Manager was Dr. Edward M. Hunter.

The study management at NASA-Lewis was directed by William A.

Poley.

1.2 STUDY OBJECTIVES

The specific goals of the Communications Platform Payload

Definition Study are as follows:

o Determine types of geostationary communications payloads

applicable to a large platform, circa 1998

o Provide concept system architecture

o Provide payload concept and description

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o Provide comparisons including estimated cost and

technology risk

o Identify high payoff technology

In the context of this study, "large geostationary facility"

means a very large (i.e.. greater than 5,000 pounds) satellite, a

platform, or a cluster of satellites colocated at a single

geostationary orbit slot. "Communications payload" refers to

those subsystems which provide voice. video.- or data

communications services. Not included in the "payload" are

subsystems providing the functions of attitude control,

stationkeeping. and power generation.

The study evaluated the impacts of new traffic forecasts and

estimates of the new services to be provided in order to provide

NASA with answers to the following questions:

o Is the existence of one or more large scale geostationary

facilities, each consisting of a payload providing a

single communications service or a variety of

communication services, desirable in the mid to late 1990s?

o If so. what are the most viable operational systems

(payload, spacecraft. transportation, and space

operations) for that time frame?

o For those operational systems. what enabling and

supporting technologies are required prior to

implementation and, in particular. which of those

technologies is of high technical and/or economic risk?

1.3 GUIDELINES AND CONSTRAINTS

The scope of this study was controlled by several NASA

directed as well as contractor recommended guideline and

constraints. Among these were:

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o Utilization of 1998 operational technology (mature status

1993)

o No in-orbit payload assembly

o Minimum system lifetime of ten years

o Conformance to "anticipated" regulatory requirements

o "Baseline" configurations limited to communications

payloads only

o Institutional issues ultimately not a barrier

o Must be economically feasible

o Must be based on demonstrated need

o Accommodate user/operator requirements

In addition to the above constraints Ford Aerospace added the

constraint that "Baseline" configurations be constrained to rigid

reflectors for FSS and DBS

The various communications service aggregation scenario

configurations were to include at least two "baseline" systems

and at least two "variations". The coverage and frequency

planning for each is as follows:

a_. Baseline Requirements

- Up to CONUS coverage

- U.S. domestic FSS and DBS services only

- C/Ku/Ka frequency bands

b_. Variation Requirements

- Service coverage area up to entire western hemisphere

(WARC region 2 + Intelsat)

- Additional services: mobile (land. sea. air), data

collection, others

- Intersatellite link capability to international

satellites or other non-U.S. satellites or platforms

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The various scenario configurations were to be based upon

either of the following two launch concepts:

o Launch Concept 1: up to a maximum single shuttle launch

of combined spacecraft and upper stage with a spacecraft

weight of up to 12,000 pounds

. o Launch Concept 2: allows a separate spacecraft (without

upper stage) of size and weight up to a full shuttle

launch capability (65.000 pounds)

1.4 STUDY APPROACH

The NASA SOW organized the study into an orderly sequence of

tasks. These tasks support the study outputs by successively

accomplishing:

Task 1: Assemble a data base consisting of traffic models.

market forecasts. technology forecasts. criteria for

selection and evaluation. and cost estimating

methodology to be used for the remainder of the study

tasks.

Task 2: Using the data base and criteria select at least six

service aggregation scenarios for development and

evaluation. Hold an informal briefing at NASA LeRC to

review the scenario ranking and select scenarios for

further development.

Task 3: Develop payload concepts for four of the service

aggregation scenarios developed in Task 2.

Task 4: Develop four detailed payload system configurations for

the concepts developed in Task 3. and define the payload

to the component level.

Task 5: Provide a system cost estimate and identify cost drivers

for the payload configurations.

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Task 6: Identify both enabling and supporting technologies

critical to the eventual implementation and operation of

each of the concepts.

Task 7: Provide system comparisons between the communications

payloads.

Interim presentations were made at NASA Lewis Research Center

on 27 September 1984 and 7 February 1985. and the final review

presentation was held on 16 July 1985. Three additional interim

review meetings were held at Ford Aerospace in Palo Alto.

California as well as a bus study contract interface meeting.

The general methodology which was utilized to generate the

development planning information on performance and costs is

shown in Figure 1.4-1. The traffic analysis. performance

standards and network analysis leads to overall communications

reguirements expressed in number and types of channels. The

systems analysis effort then postulates candidate systems,

evaluates, and defines selected concepts. The systems design

effort provides hardware definition of space and ground segments

which serves as the basis for costing and other development

planning outputs.

1.5 SUMMARY DESCRIPTION

Several satellite demand forecasts have indicated a growing

pressure on arc/spectrum resources. More efficient use of this

scarce resource will be reguired to meet projected demands in the

year 2000 and beyond. In addition. economic pressure from

terrestrial systems such as fiber optics will require a

significant reduction in per-circuit costs in order for satellite

systems to remain competitive, especially for point-to-point high

density routes.

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Figure 1.4-1 Development Planning Methodology

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Corporation is a supplier of

total communications

systems. Key to successful

and cost-effective

implementation is precise

analysis and planning.

TRAFFIC

ANALYSIS

PERFORMANCE j.

STANDARDS '

. j NETWORK

I; ANALYSIS

NUMBER AND

TYPES OF

CHANNELS

REQUIRED

! CANDIDATE

SYSTEMS

SYSTEMS

DEFINITION

COMMUNICATION

REQUIREMENTS

SYSTEMS ANALYSIS

I" SYSTEMS

1RCATIONS

AND :

^CONCEPTS OF1 OPERATION

SPACE SEGMENT

GROUND SEGMENT

r -

Ejr-^r

TERRESTRIAL

COMMUNICATIONS

SYSTEMS DESIGN

FSPEaFICATIONS

AND

v

 '$* -'--'. ' ""' . • -

•-; •"•'*±---. -:!..• i.'.;.":::-

DEVELOPMENT PLANNING

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,-.- . *

In the point to multi-point applications such as DBS and data

gathering, the satellite should have a natural advantage over

land distribution systems. However in the U.S. the existing land

based distribution system is extensive and already in place and

will be very difficult to replace.

A potential solution to these problems is the use of large

geostationary platforms which can provide significant improvement in the communications capacity of an orbital slot as well as

economies of scale.

This study describes several scenarios which provide an

increasing capability to serve projected Region 2 traffic.

Briefly these scenarios are:

o A medium capacity CONUS FSS and medium power DBS capability

o A high capacity medium and high power video distribution

capability

o A high capacity CONUS FSS capability

o A complementary pair of satellites with the high capacity

CONUS FSS capability above and in addition, incorporating

intersatellite links to "European" and "Asian" platforms

to carry all Region 2 international traffic. plus

providing all non-U.S. domestic coverage in the Western

Hemisphere, as well as all maritime service in the Western

Hemisphere.

The first three scenarios are sized such that the platform,

upper stage and fuel can be carried to low earth orbit (LEO) with

a single shuttle launch; the last scenario would require multiple

shuttle launches with in-orbit assembly of spacecraft and upper

stage, and/or fueling at the Space Station or GEO servicing.

For each scenario, this report describes the various payloads.

antenna requirements, hardware implications (including on-board

processing) and modulation/access methods. Finally, the

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advantages and disadvantages of each scenario are discussed

relative to such factors as launch considerations, institutional

barriers, reliability, and economics.

1.6 ORGANIZATION OF FINAL REPORT

The final report describing the findings of the Communications Platform Paylpad Definition Study is contained in three

volumes. Volume I, Executive Summary. CR-174928. provides a

brief overview of the payload descriptions and key findings.

Volume II. Final Technical Report. CR-174929. provides the

detailed information on the study data base (Task 1). aggregation

scenario development (Task 2). payload concept development (Task

3). payload definition (Task 4). cost estimates (Task 5).

critical technology (Task 6). and system comparison (Task 7).

Additional supporting detail is contained in Volume III.

Addendum to Final Technical Report, CR-174930. This includes

descriptions of traffic models, traffic surveys, satellite and

ground system profiles, and payload details for all developed

scenarios.

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SECTION INDEX

Page

2.0 DATA BASE (TASK 1) 2-1

2.1 OVERVIEW 2-1

2.2 TRAFFIC FORECASTS 2-3

2.2.1 Introduction and Summary of Traffic Demand vs Supply 2-3

2.2.1.1 Approach to Traffic Forecast 2-3

2.2.1.2 Summary of Traffic Demand vs Supply 2-10

2.2.1.3 Breakdown of Summary Satellite Demand 2-13

2.2.2 U.S. Domestic Traffic Forecast 2-17

2.2.2.1 Results of Industry Survey 2-17

2.2.2.2 Fixed Satellite Demand (U.S. Domestic) 2-18

2.2.2.3 Direct Broadcast Satellite Service (U.S. Domestic) .2-18

2.2.2.4 Mobile Satellite Service (U.S. Domestic) 2-20

2.2.3 Non U.S.Domestic Traffic Forecast 2-21

2.2.3.1 Fixed Satellite Service 2-21

2.2-3.2 Direct Broadcast Service 2-25

2.2.3.3 Mobile Satellite Service 2-26

2.2.4 Regional Services Traffic Forecast 2-27

2.2.4.1 Regional Service- U.S. to/from Canada 2-28

2.2.4.2 Regional Service - U.S. to/from Latin America & 2-28

Caribbean

2.2.4.3 Regional Service - Intra Latin America & Caribbean 2-30

2.2.5 International Traffic Forecast 2-31

2.2.5.1 Atlantic Ocean Region (AOR) 2-31

2.2.5.2 Pacific Ocean Region (POR) 2-33

2.2.6 Maritime Services Traffic Forecast 2-34

2.2.7 Future Growth for Traffic Forecast to Year 2008 2-35

2.3 TRAFFIC DISTRIBUTION MODELS 2-36

2.3.1 Approach 2-36

2.3.2 NASA FSS Model 2-38

2.3.3 Intelsat FSS Model 2-38

2.3.4 Other Distribution Models 2-39
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SECTION INDEX (Cont.)

Page

2.4 SPACE AND TERRESTRIAL SUPPLY FORECAST 2-43

2.4.1 Overview 2-43

2.4.2 Estimate of Satellite Transponder Supply 2-47

2.4.3 Terrestrial Terminal Supply 2-50

2.4.3.1 Terminals in Support of FSS and DBS Service 2-55

2.4.3.2 Terminals in Support of Mobile Service 2-58

2.5 CONSTRAINTS, SELECTION CRITERIA. AND OTHER 2-60

CONSIDERATIONS

2.5.1 Study and Task Constraints 2-60

2.5.2 Service Aggregation Scenario Selection Criteria 2-61

2.5.3 Payload Concept Evaluation Criteria 2-63

2.5.4 Other Consideration 2-63

2.5.4.1 Institutional Barriers 2-64

2.5.4.2 Regulatory Considerations 2-72

2.5.4.3 Insurance Issues 2-74
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2.0 DATA BASE

2.1 OVERVIEW

The purpose of task 1. Initialization and Data Base

Development, was to develop the foundation material required to

support the subsequent study tasks 2 thru 7. NASA provided

references 1 through 7 as the initial data base. During the

study, references 8 through 53 were compiled and used in various

phases of the effort. A summary of the task outputs included:

o Overall study and task constraints

o Communication service aggregation scenario selection

criteria.

o Payload concept evaluation criteria,

o Traffic forecasts and distribution models,

o Forecasts of space and terrestrial plant-in-place.

o Communications technology forecast,

o Cost estimating methodology.

This material was presented to NASA Lewis Research Center.

Cleveland, Ohio, in a Task 1 Review held on 27 September 1984.

The data base information has been organized into the

following sections of this report:

Traffic Forecasts (Section 2.2)

This Section contains the forecast of communications traffic

for the categories of A) U.S. Domestic B) Non U.S. Domestic C)

Regional Services D) International Traffic (Region 2 to other

regions) and E) Maritime. A breakdown of fixed services

(voice. video and data). direct broadcast and mobile is

included. The approach to this subtask was to utilize the NASA

supplied models of U.S. commercial traffic supplemented by other

models developed by Ford Aerospace and it's associate contractor

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Satellite Systems Engineering. Inc. (SSE). The results of a

survey of industry, performed by SSE. on traffic requirements is

included as Appendix D.

Traffic Distribution Models (Section 2.3)

The section addresses the distribution patterns of the

traffic projected in Section 2.2 The projections were based

upon use of the NASA FSS model, the Intelsat FSS model, and

others developed for this study. Supplementary material is also

included in Appendices A, B, and C of Volume III of this report.

Space and Terrestrial Supply Forecast (Section 2.4)

This section defines the availability of spacecraft

transponders and terrestrial terminals over the period from

present up to 1998. Additional detail on satellite system

models is included as Appendix E to this report.

The space segment estimates include the number of satellites.

orbit locations, and traffic carried. The terrestrial segment

estimates include information on the traffic carried,

transmission mode split, numbers of earth stations serving the

space segment, ranges of sizes and types of earth stations, and

frequency bands utilized.

Selection Criteria and Constraints (Section 2.5)

This section summarizes the overall study and task

constraints imposed by NASA, defines the service aggregation

scenario selection criteria, defines the payload concept

evaluation criteria, and addresses other general constraint

issues including a) institutional barriers b) regulatory

considerations and c) insurance issues.

Additional Task 1 material related to payload servicing

forecasts and communications technology forecasts is presented

in Section 7 of this report.

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2.2 TRAFFIC FORECASTS

2.2.1 Introduction and Summary of Traffic Demand vs Supply

2.2.1.1 Approach to Traffic Forecast

The purpose of the traffic forecast subtask of Task 1 was to

assemble, develop, and/or synthesize traffic forecasts and

models required by the study and not furnished by NASA. This

information was supplemented by a NASA provided synthesis (Ref.

8) of the results of the most recent Western Union (Ref. 1 and

2) and I.T.T. (Ref. 3) demand studies, completed in the summer

of 1983.

The requirement for a large space platform is ultimately

dependent on the anticipated need from the end users, not only

to enable optimal design of the platform but also for the

continued justification of the requirement for the

communications payload. .

There is certainly no dearth of demand studies for

communication satellites in the next 15-20 years. There are

forecasts that have been produced on a regular basis to be sold

to the industry at large. There are forecasts that have been

produced on a contract basis to support FCC application and

business plans of would-be satellite operators. There are also

forecasts that have been produced under contract to NASA, or

other government agencies, in support of various programs. As

might be expected, the methodologies and assumptions used by the

various demand studies have varied considerably, resulting in

some dramatically different results, but. until very recently,

almost all forecasters agreed in their assessment of almost

exponential growth in the demand for satellite communication,

with no slowdown in sight. The only perceived constraint to

this growth was not a slackening of demand, but rather the

saturation of the orbital arc and an inability to build and

launch enough satellites fast enough to cater to the demand.

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The most obvious recent proof of the optimism is the number

of applications for FSS licenses received at the FCC in November

1983. If all of the satellite systems currently authorized and

pending at the FCC were approved (and financed), the number of

commercial C and Ku-band satellites in orbit would grow from 18

at year-end 1983 to 32 by year-end 1985. 78 by year-end 1990.

and 111 by year-end 2000 (assuming one for one replacement at

the end of the expected design life and no new systems).

Already. one of the November 1983 applicants. American

Satellite, has proposed a Ka-band package in their planned

system, and in December 1983 Hughes Communication became the

first company to propose a commercial all Ka-band satellite

system.

Despite these events, in recent months there has been some

uncertainty heard in the forecasting world. One recent demand

projection, the report of Working Group A-l (WGA-1) of the FCC

advisory Committee on Space WARC '85 (Ref. 10) was somewhat more

cautious in it's outlook for the satellite communications

industry.

WGA-1 used two different approaches to develop their demand

estimates, the average of which was 10% lower than Western

Union's (1983) demand projections and 25% lower then I.T.T.'s

(1983) demand projections.

The most probable stimulus for this more cautious view of

future growth in satellite demand is the current "buyers's

market" for satellite transponders. There are a number of

transponders available on operational satellites and many more

available on satellites to be launched in 1984 and 1985

(especially GTE's G-Star and Spacenet Systems). With the supply

of transponders about to double in the next 2-3 years, some hard

questions are beginning to be asked about those demand studies

predicting virtually unlimited growth.

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This taraporary shifting in the satellite marketplace should

be seen as the natural result of two factors:

1. A predictable slowdown in growth of the two major

applications that spurred the growth of the commercial

satellite industry in the 1970's - point-to-point heavy

trunking telephony and cable TV distribution

2. Slower than expected growth in some of the newer services

that were expected to drive satellite demand in the

future - video conferencing. DBS. and private corporate

networks

With the fairly rapid introduction of both SSB-AM microwave

and fiber optics into the terrestrial transmission systems (and

the related decision by AT&T to keep most of their long-distance

voice traffic off their satellite), it has become obvious that

high density point-to-point traffic does not exploit the true

advantages of satellite transmission, especially when there is a

substantial terrestrial infrastructure in place. Voice will

continue to be a major component of satellite demand but in the

context of many smaller networks and with emphasis on remote

locations and lower density traffic.

The distribution of video signals from a network center to

cable franchises is a natural use of satellites, and this

application provided the spark that ignited the growth of the

commercial satellite industry. But the cable T.V. industry is

also in a period of reshuffling, facing competition from new

technologies such as LPTV, MDS. private cable, etc, and weeding

out of some of the poorly managed and conceived programming

services (eg, CBS cable, the Entertainment Channel, etc). In

the long run, the television industry will continue to be a

major user of communication satellites, as the recently

announced satellite interconnection plans of the three

commercial TV networks illustrate.

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The reasons for the slower than expected growth in some of

the newer services are ultimately cost-related. Almost all

video conferencing so far has been full broadcast quality, using

an entire transponder. Until most video conferencing can be

compressed into less bandwidth (ie. 1.544 Mb/s or even 56 kb/s)

with acceptable quality, the costs of video conferencing will be

inhibiting. Similarly, the growth of private corporate networks

has been hampered by the high cost of earth stations and

accompanying equipment. The advent of DBS has been slowed by

regulatory hurdles and the uncertainty over the optimal mix of

cost and sophistication in the sky and cost and sophistication

on the ground.

What is occurring now in the satellite industry is a more

critical assessment by users of the advantages and disadvantages

of satellite communications, compared to other transmission

media. And what is now becoming clear to users is that the

major operational advantages of satellites are in

point-to-multipoint. and multipoint-to-multipoint applications.

It is in these applications that the instant networking feature

of a satellite network becomes most dramatic. In the next

decade and beyond, the industry will understand better these

market (and economic) realities, leading to rapid growth in

those areas where satellite communications are most suited.

It is projected that the new growth areas will come from the

following:

o Video Conferencing - Analysts still believe that video

conferencing will have a major impact on future demands

for network capacity. As video conferencing costs fall

due to economies of scale in the provision of service and

the transition to all-digital service (leading to more

efficient compression techniques), demand for the service

will grow dramatically. Combined with the continued rise

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in the cost of trave.l and the increased productivity by

not travelling, video conferencing should evolve into a

major component of demand in the next 25 years.

CPT-CPT - Often the most expensive and difficult

component of any transmission system is the local

distribution link. Direct satellite links between

customer premise terminals (CPT) offer the opportunity to

avoid local distribution problems entirely. As earth

station prices continue to decline and more efficient

transmission modes (eg, thin-route TDMA) are introduced,

this option becomes cost effective to a larger number of

users. I.T.T. (Ref. 3) foresees CPT-CPT traffic as 20%

of the total satellite market by the year 2000. while

W.U. (Ref. 2) estimates this application as 25% of the

total satellite market by 1990. Another report forecasts

growth in thin route earth station sales revenues from $3

million in 1981 to $175 million in 1991. reflecting an

annual compound growth rate of 50%.

Personal Computer Networks - As the personal computer

market continues to grow, there will be a burgeoning need

for low-volume data communication links direct to the

telephone line. A recent study predicted growth in

household ownership of personal computers with modems

from almost none in 1982 to nearly 5 million in 1985. It

also predicted the number of electronic mail users

expanding from 10.000 in 1982 to almost a million by

1986. Much of this communication can be handled over the

telephone local lines, but there will be an increasing

need for visual and graphic forms of communication,

requiring more bandwidth than the local telephone

companies can supply.

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DBS - Depending on whom you believe. DBS represents

nothing less than the next generation of TV program

delivery or nothing more than an idea whose time has come

and gone. In theory. DBS is the most natural application

for satellites, with millions of small. inexpensive

ground stations instantly connected in a network via a

very powerful satellite. The major drawback to DBS in

this country is not the DBS technology itself, but a well

entrenched broadcast and cable industry with billions of

dollars of plant in place. There is an initial potential

market of 10-20 million homes for DBS in the next 10

years or so, and if DBS systems gain a foothold, the

cable industry will find it hard to compete when the time

comes for upgrading or replacing their existing plant.

The key to the success of DBS is the need to reduce the

costs of building and launching these larger, more

powerful satellites.

Mobile Satellites - With the coming boom in cellular

radio, there will be a sizable market for connecting

those areas outside of SMSA coverage, including rural and

offshore areas. There is already an application for a

commercial mobile satellite system on file at the FCC.

and Canada has plans to build a mobile satellite for its

own national needs.

Data Gathering - Essentially the mirror image of DBS

(multipoint-to-point). this is an application that has so

far been used mostly for earth remote sensing and weather

monitoring, but holds much promise for such

labor-intensive services as meter reading. security

monitoring of businesses and homes, oil well management,

and myriad other uses. Already the Association of Rural

Utilities is considering the use of satellites for the

reading of gas and water meters outside of major cities.

The potential for these types of services is enormous.

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What is common to all of the above-listed services is the

requirement for sophisticated satellites using large antennas.

high-powered transmitters, and sensitive receivers. What also

is common is the need for these communication services to be

offered at competitive prices. And the most obvious way to help

keep the price of such services down is to take advantage of the

economies of scale inherent in placing various communication

packages on a large space platform.

The methodology utilized to establish the traffic forecast

included the following steps:

a.. Conduct a literature search of all existing forecast

data, both international and domestic.

b. Conduct a series of industry surveys to fill in the gaps

of existing forecasts with special emphasis on both the

user community and those services not addressed by the

forecasts (eg. data gathering, private computer networks,

etc).

c_. Convert the traffic data base into meaningful units, eg,

(1) Data - bits per second (b/s)

(2) Video - channels

(3) Voice - circuits

(4) Mobile satellite - circuits

(5) Data gathering - b/s

d_. Quantify traffic data base in terms of types of usage and

distribution of traffic. The temporal and spatial

distribution of the flow of communications is needed for

optimal system design. This distribution would vary with

the service offered and included the following traffic

allotment as appropriate:

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(1) By earth station

(2) By SMSA

(3) By other defined region

(4) By CONUS

2.2.1.2 Summary of Traffic Demand vs Supply

This section summarizes the overall demand/supply for

communications traffic in Region 2. The traffic data base is

based upon the following:

a NASA Model for CONUS FSS and CPS

b SSE estimates for DBS

c Mobile estimates based on GE forecast

d Maritime estimates based on Inmarsat forecast

e International and intra Region 2 based on INTELSAT

Forecast of August 1984

f Non-U.S. domestic Region 2 from various sources

g Forecast extrapolation based on Ford Aerospace/SSE

estimates

The orbit spares philosophy has significant impact on

supply/demand projections. This study has added the following

factors to demand in order account for sparing requirements:

U.S. Domestic None

Non-U.S. Domestic & Regional 50%

International 50%

The following assumptions were used in determining the

sparing factor:

a. U.S. domestic sparing factor is probably in the 20-30%

range, however the U.S. domestic traffic base addresses

satellite addressable traffic only, and it was felt the

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traffic actually carried via satellite would reduce the demand

by approximately the same percentage as sparing requirements

would add to demand.

b. Non-U.S. domestic and regional traffic requires

conservative sparing philosophy because of critical importance

of national telecommunication network infallibility and lack

of alternative spacecraft to which traffic could be rerouted.

c. International traffic also requires conservative sparing

philosophy because of international agreements and requirements of sophisticated switching on board the satellite.

A summary of demand versus supply projection for the various

satellite communications services follows:

A. Demand/Supply for Fixed Satellite Services

The summary shown in Table 2.2.1-1 represents the aggregation

of demand from voice, video and data services. Demand summaries

have been converted to equivalent 36 MHz transponders to show

projected demand vs. supply in the same unit. Conversions were

made according to the capacity loading factor in Table 2.2.1-5.

Table 2.2.1-1

Fixed Satellite Services

(In Equivalent 36 MHz Transponders)

1990 2000

U.S. Non-U.S U.S. Non-U.S

* **

Supply 1048 384 1951 574

*** ***

Demand 1024 182 2150 270

* Assumes constant growth from 1995

** 1995 Estimate

*** Including 50% sparing factor

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B. Demand/Supply for Non-Fixed Satellite Services

Table 2.2.1-2 compares the best estimate of supply for U.S.

and Non-U.S. DBS. mobile and maritime services. Transponders

are equivalent, but for each service (i.e. voice, video, data) a

separate conversion factor was used.

Table 2.2.1-2

Non-Fixed Satellite Services

DBS (In Channels)

(In Equivalent 36 MHz Transponder)

1990

U.S. Non-U.S

2000

U.S. Non-U.S,

Supply 10 42 12

Demand 24 50 20

Mobile Services

(In 4 MHz Transponders)

Supply

Demand 23 0.2 75

Maritime Services

(In Equivalent Inmarsat 2nd Generation Transponders)

Supply

Demand

* - 1995 Estimate

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2.2.1.3 Breakdown of Summary Satellite Demand

This section details the component segments of the summary

satellite transponder demand projected in Table 2.2.1-2.

Highlights of the demand forecast include:

1. Little change from NASA - provided U.S. FSS demand model.

Outstanding issue — effect of fiber optics

2. Non-U.S. FSS features moderate to high growth, based on

current and projected traffic.

3. DBS (includes high power and medium power services not

addressed by NASA model) shows low to moderate growth.

4. Mobile services have very high demand in U.S.(based on

G.E. forecast) and low demand elsewhere

5. Maritime services show moderate growth (based on Inmarsat

projections)

A summary of projected traffic demand as a function of

communications mode follows:

A. Fixed Satellite Demand

Table 2.2.1-3 shows the breakdown of US Domestic fixed

satellite service demand for voice, video, and data segments

(Ref. 8) is the source for this demand.

Table 2.2.1-4 combines all estimates of FSS demand that were

considered for traffic between Canada-U.S.-Latin America;

Canada-Latin America; Intra Latin America; Atlantic Ocean Region

(AOR); and Pacific Ocean Region (FOR). Figures are taken from a

combination of sources including the August 1984 Intelsat

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Table 2.2.1-3

U.S. Domestic Fixed Satellite Demand

(Voice-Half Circuits. Video-Channels. Data-Peak Hr. Mb/s)

1990 2000

Voice 1.831.000(654) 6.849.000(1522)

Video-Broadcast Ch. 158(79) 233(78)

-Video Conf. 1.971(56) 8.225(176)

Data 12.687( 235) 26.945(374)

TOTAL TRANSPONDERS* (1,024) (2.150)

* Equivalent 36 MHz Transponders

Table 2.2.1-4

Total Non-U.S. Domestic. Regional. And International FSS Dem

and

(Voice-Half Circuits. Video-Channels. Data-Peak Hr. Mb/s)

1990 2000

Voice 148.823(53) 332.361(74)

Video 144(57) 274(91)

Data . 461( 9) 1.081(15)

TOTAL TRANSPONDERS* (119) (180)

* Equivalent 36 MHz Transponders

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database (Ref. 9). various applications for satellite and fiber

optic services e.g.. (Ref. 20), past traffic trends and other

secondary industry sources.

Raw estimates have been converted into equivalent 36 MHz

transponders according to the capacity loading of Table 2.2.1-5.

Table 2.2.1-5

Capacities Per Equivalent 36 MHz Transponder* Year

ITEM 1985 1990 2000

**

1/2 Voice Cir 1200 2800 4500

Broadcast x 2 3

Video Channels

***

Data Mb/S 36 54 72

* Use of small terminals will limit capacities

** Weighted average voice channels for all applications

*** Includes video conferencing

B. Direct Broadcast Satellite Demand

Table 2.2.1-6 shows the summary of direct broadcast satellite

demand for the combined U.S. Domestic, Canadian, and Latin

America/Caribbean regions ie. WARC Region 2.

Table 2.2.1-6

Direct Broadcast Satellite Demand

U.S. Domestic. Canada. Latin America & Caribbean Region

(in Channels)

1990 2000

LOW 12 32

BEST 24 70

HIGH 32 96

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C. Mobile Satellite Demand

Table 2.2.1-7 shows the projected mobile satellite demand for

years 1990 and 2000.

These figures were based upon the General Electric study done

for NASA (Lewis) (Ref. 15) and the Canadian Phase B market study

done for Telesat. The U.S. portion represents over 90% of

demand. No market demand is foreseen for Latin America and

Caribbean by the year 2000. The potential market for radio

determination and positioning services are reflected in these

numbers.

Table 2.2.1-7

Mobile Satellite Demand

U.S. Domestic. Canada and Latin America

In Users and (4 MHz Transponders)

Voice (2 way)

U.S.

Non U.S.

1990 2000

217.000 (9.0) 1.130.000 (47.0)

2.000 (0.1) 20.000 (1)

Voice (1 way)

U.S.

Non U.S,

557.000 (12.0) 1.245.000 (26.0)

6.000 (0.1) 60.000 (1)

Data (Low Speed)

U.S. 175.300 (2.0) 205.000 (2.0)

TOTAL TRANSPONDERS (23.2) (77)

* 24,000 Users per Transponder

** 48.000 Users per Transponder

*** 96.000 Users per Transponder

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The conversion from number of users to requirements for 4 MHz

transponders were based on the following assumptions taken from

mobile satellite applications:

o One 4 MHz transponder can be divided into 800 5 KHz

channels

o Each channel can accommodate 30 two-way voice users, 60

one-way voice users or 120 (low speed) data users.

Applicants for proposed mobile services believe there will be

more demand for low speed data than is reflected in these

estimates.

2.2.2 IKS. Domestic Traffic Forecast

This section provides detail on the fixed service, direct

broadcast, and mobile service traffic demands for the U.S.

Domestic Traffic.

2.2.2.1 Results of Industry Survey

There are no changes in the fixed services forecast from the

NASA Communications Traffic Synthesis. SSE did not analyze

video or voice traffic estimates. However further analysis was

provided for demand for data services in the following

categories: remote job entry, inguiry/response. timesharing,

point of sale, videotext/teletext, telemonitoring, and secure

voice. It was assumed that these 7 categories included all of

the 'new1 services for which SSE attempted to quantify demand.

A series of industry surveys were conducted, with emphasis on

those companies likely to be telecommunications users in the

above categories. (See Appendix D for a list of industry survey

respondents and analysis of those responses.) Major trends

revealed were: integration of services; high demand for remote

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job entry (RJE) and telemonitoring mostly satisfied by mobile

satellites; timesharing growth captured largely by fiber

optics; and more long haul traffic in inquiry/response, and in

point of sale transactions. It is not expected that these

developments will significantly alter the NASA traffic data base.

2.2.2.2 Fixed Satellite Demand (U.S. Domestic)

Table 2.2.2-1 summarizes the voice, video, and data segments

of the U.S. domestic fixed satellite demand.

Table 2.2.2-1

Fixed Satellite .U.S. Domestic Demand

(Voice-Half Circuits. Video-Channels. Data-Peak Hr. Mb/s)

Year Year

1990 2000

Voice 1.831.000 6.849.000

Video

Broadcast Channels 158 233

Video Conferencing 1.971 8.225

Data 12.687 26.945

2.2.2.3 Direct Broadcast Satellite Service (U.S. Domestic)

Direct broadcast services considered were from either medium

or high powered satellites. (Channel estimates reflect zonal

coverage; i.e.. half-CONUS channels). 65% of U.S. T.V.

households (approximately 87 million) are presently cable (half

of these homes are actual subscribers); it is probable that 25%

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will remain uncabled due to high installation costs per mile. A

limited market for DBS exists in cabled areas since about 50% of

current systems are only 12 channel systems.

The only real competition to DBS in non-urban areas is from

the backyard TVRO market, receiving C-band video. However.

o

because of scrambling, 2 spacing and legal uncertainties, the

fully saturated market for C-Band TVRO's is estimated at 2

million. Of first round DBS licensees, only Comsat's Satellite

Television Corporation (STC) actively started building it's high

powered DBS system, although it is unclear exactly what type of

services it will provide. Dominion Video, USSB, and DBSC are

still in the process of securing financing. Four second-round

applicants have also received authorization to construct direct

broadcast satellites.

While system costs are high, and DBS may eventually be

offered on medium powered satellites rather than high powered

ones, the market for DBS seems to exist for 2 systems by the end

of the decade and about 4-5 systems by the year 2000.

A summary of the direct broadcast traffic demand is shows in

Table 2.2.2-2.

Table 2.2.2-2

Direct Broadcast Satellite Demand (U.S. Domestic)

(In Channels)

1990 2000

LOW 12 32

BEST .2 4 5 0

HIGH 32 64

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2.2.2.4 Mobile Satellite Service (U.S. Domestic)

The .Mobile Satellite Service (MSS) encompasses three main

service categories: a) mobile radio telephone b) other voice

services (include commercial and public radio, and voice service

to oil and gas companies and the trucking industry), and c) low

speed data services (alpha - numeric messaging, dispatch,

position surveillance, etc.) The two main quoted market studies

for mobile services are the traffic model prepared by GE in June

1983 for NASA Lewis and subsequently referenced in the Mobilsat

application (Ref. 15) and the market study prepared for NASA in

November 1982 .by ECOSYSTEMS International and subsequently

referenced by Skylink, and used as the traffic base model for

the TRW contract under NASA Lewis (Ref. 25). The GE traffic

base was used by SSE as the best traffic base for mobile

services. The ECOSYSTEMS forecast fell in between the

'conservative' and 'likely1 scenarios of GE. (i.e.. 179,000

potential mobile users in 1990). The main uncertainty in GE

traffic base is the assumption that there will be no land-based

mobile radio outside of SMSA's.

In addition to the forecast of traffic for the MSS. there is

an application pending at the FCC by Geostar for a satellite

system offering service in the radio-determination area.

Geostar. in recent conversations, has alluded to an overall

market of approximately 9 million users by 1995. Each user

would have a pocket calculator-sized terminal capable of

receiving and sending brief alpha-numeric messages, and would be

able to be constantly positioned by the Geostar computer

facility to a distance of a few meters. This number appears

extremely optimistic, and the inability of the Geostar system to

offer voice services is. in our view, an inhibiting factor to

its potential for operation.

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SSE concluded that the demand for messaging and positioning

services is more accurately reflected by the Mobilsat estimates,

and that such services are more likely to be carried on a

satellite such as Mobilsat or Skylink.

Table 2.2.2-3 summarizes the expected mobile satellite demand

for voice and data for the time period of 1990 and 2000.

Table 2.2.2-3

Mobile Satellite Demand (U.S. Domestic)

(In Number of Users)

1990 2000

DATA 175.000 205.000

VOICE (1 way) 557.000 1.130.000

(2-way) 217.000 1.245.000

2.2.3 Non U.S.Domestic Traffic Forecast

This section details the traffic forecast for Canada and the

Latin America/Caribbean areas for FSS. direct broadcast and

mobile services communications segments.

2.2.3.1 Fixed Satellite Service

Canada Voice Traffic:

The traffic demand projections listed in Table 2.2.3-1 were

based on actual traffic carried on Anik C Ku-Band (5 city node)

for switched services plus Anik D C-band for Northern services.

This includes data traffic, expressed in equivalent voice grade

channels. Very little private network service is currently

carried via satellite. Telecom Canada has adjusted overall

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switched voice traffic growth forecasts downward and only small

growth is seen in switched services via satellite.

Future growth is projected in various private line services,

including: high speed data (by Globe & Mail newspaper; Mobile

Oil). ISDN, off-shore communications, and other private network

users. Increased competition between Telecom Canada and CNCP

telecommunications is likely to spur growth. thus, overall

voice traffic carried via satellite will double between 1985 -

1990 (approximately 14% per year), and then triple between

1990-2000 (approximately 12% per year).

Table 2.2.3-1

Canada Voice Traffic (Non-U.S. Domestic)

(Half-Circuits)

1985 1990 2000

10.000 20.000 60,000

Latin America & Caribbean Voice Traffic:

The projected demand shown in Table 2.2.3-2 is based on

analysis done by Working Group A-l of FCC Space WARC 1985.

Advisory Committee (Ref. ). Projections were made on expected

requirements of the nine countries that are likely satellite

users for domestic traffic The working group considered

demographic and economic variables; regression analyses were

also performed to forecast long distance telephone calls, and

ultimately the number of circuits required. It was assumed that

countries in these areas would place a larger proportion of

circuit growth on satellites. due to lack of extensive

terrestrial infrastructure. Voice projections also include some

data traffic.

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Table 2.2.3-2

Latin America/Caribbean Voice Traffic (Non-U.S. Domestic)

(Half-Circuits)

1985 1990 1995 2000

Argentina

Bolivia

Brazil

Chile

Colombia

Ecuador

Mexico

Peru

Venezuela

167

60

13.974

446

341

60

2.423

35

45

725

138

20,904

1,001

1.712

138

7.916

80

240

1315

220

29.684

1.689

3.254

220

14,037

128

491

1830

314

40.574

2.574

4,840

314

20.797

179

803

TOTAL 17.550 32,881 51.038 72.193

Canada Video Traffic;

The Canadian Video Demand shown in Table 2.2.3-3 is based on

actual traffic on Anik during period of 1975-1983. A stable

rate of growth for video service is expected due to slower

growth for pay T.V. A strong demand for provincial educational

television is not expected to materialize. Approximately half

of the video services serve the Arctic region and half are for

program distribution by T.V. networks. Little, if any

videoconferencing is currently carried on Anik. Nonetheless,

interest in video is high, and the projected demand reflects

moderate needs by the private sector over the next 15 years.

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Table 2.2.3-3

Canada Video Traffic (Non-U.S. Domestic)

(Channels)

1985 1990 1995 2000

Broadcast T.V. 33 40 50 60

*

Videoconferencing 0 5 10 30

TOTAL 33 45 60 90

*

Expressed in Broadcast Quality Video Channels;

1 Broadcast Channel=20 Videoconferencing Channels.

Latin America/Caribbean Video Traffic:

Intelsat traffic and video projections to 1985 were used on

the base for the video traffic projected in Table 2.2.3-4.

Steady growth in Latin America is expected for video

distribution channels. Reguirements in Mexico. Brazil.

Venezuela and Colombia account for most of the demand in 1984

and will continue to dominate demand. This estimate tracks

towards the low end of the PANAMSAT forecast (which doesn't

include video forecasts for Mexico and Brazil). Video traffic

is expected to be carried on the Brazil and Mexican domestic

satellite systems ( and any other future or regional satellite

systems) and is included in the above estimate.

It is not expected that there will be a large demand for

domestic videoconferencing in this region. A minor demand for

videoconferencing is included in the above forecast.

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Table 2.2.3-4

Latin America/Caribbean Video Traffic

(Non U.S. Domestic)

(Channels)

1985 1990 1995 . 2000

Broadcast TV 15 24 33 40

*

Videoconferencing 0 _i ' _3_ 5

TOTAL 15 25 36 45

* Expressed in Broadcast Quality Video Channels;

1 Broadcast Channel= 20 Videoconferencing Channels.

2.2.3.2 Direct Broadcast Service

Canada Direct Broadcast Traffic:

The primary market for DBS in Canada is in rural areas and in

the North; however, these areas are already accommodated by

Ku-band video on Anik C. In addition, all major and secondary

cities in Canada are cabled, and initial pay-T.V. efforts of

last year were not very successful (4 of 7 services failed). In

view of these developments, the prospects for DBS in Canada are

not very bright with nominal traffic forecast as shown in Table

2.2.3-5.

The Canadian government has taken a go-slow approach on DBS

and the market for DBS in Canada does not appear to be firm. A

more optimistic forecast would show up to 10 DBS channels by the

year 2000.

Table 2.2.3-5

Canada Direct Broadcast Traffic (Non-U.S.Domestic)

(Channels)

1990 2000

0 10

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Latin America/Caribbean Direct Broadcast Traffic:

No traffic forecast for these areas currently exists. The

only data sources are inputs from various countries at RARC

'83. DBS is a natural application for many countries in this

region. given the lack of competitive nationwide terrestrial

distribution systems. However, the number of T.V. sets is

extremely low. and the costs of a DBS system will be extremely

high.

The most likely video distribution system will be direct to

community antenna, via low-to-medium powered satellites.

Countries that are candidates to build such systems are Brazil.

Argentina, Colombia,Venezuela, Chile, and several countries in

the West Indies. We believe that fixed satellites will carry

most of the DBS-type traffic, and have already included that

traffic in the FSS estimates. A nominal number of DBS channels

that could be offered by a higher powered satellite system,

probably in Brazil or Mexico are projected in Table 2.2.3-6. A

more optimistic outlook show up to 16 DBS channels by the year

2000.

Table 2.2.3-6

Latin America/Caribbean Direct Broadcast Traffic

(Non U.S. Domestic)

(In Channels)

1990 2000

0 10

2.2.3.3 Mobile Satellite Service

The projected demand for mobile satellite service to Canada

and Latin America/Caribbean is given in Table 2.2.3-7.

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The projections are based on results from both Phase A and

Phase B market surveys for Telesat Canada. Major portions of

usage are slated for Northern Canada which is outside of the

Trans-Canada telephone system. The latest design of the

Canadian MSAT is for a one satellite, 2-beara system, with

capacity of approximately 10,000 users. At this point, no

L-band paging, positioning or alpha-numeric messaging is slated

to be carried on the satellite. Canada would still like to have

a joint satellite with the U.S.. but is getting impatient with

lack of FCC approval for such a project. If necessary. Telesat

believes there is enough business for a dedicated Canadian

satellite.

Table 2.2.3-7

Canada, Latin America/Caribbean Direct Broadcast Traffic

(Number of Users)

1990 2000

2.000 (2-way) 20.000

6.000 (Push to talk) 60.000

2.2.4 Regional Services Traffic Forecast

This section details the traffic forecast for the regional

services in the following 3 categories:

a_. United States to/from Canada

b. United States to/from Latin America/Caribbean

c. Intra Latin America/Caribbean

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2.2.4.1 Regional Service - U.S. to/from Canada

Terrestrial links currently carry 95% of the traffic between

the U.S. and Canada. This is not expected to change

significantly over the next 20 years. At present, there is very

little U.S. - Canada commercial voice, video or data traffic via

satellite. but Telesat has been negotiating reciprocal

agreements with U.S. carriers, including American Satellite. SBS

and Equatorial.

Many industry sources believe fiber optic transmission

systems will be extensively utilized for this traffic. Any

satellite traffic would largely be customer-premise-to--

customer-premise for private networks. Based on the interest

shown by the carriers, we see this as a slowly emerging market,

and the traffic projections shown in Table 2.2.4-1 reflect this

view.

Table 2.2.4-1

U.S./Canada Fixed Services Traffic

(Regional)

(Voice - Half Circuits. Video-Channels. Data-Peak Hr. Mb/s)

VOICE

VIDEO

DATA

1990

2.000

5

10

2000

10.000

10

25

2.2.4.2 Regional Service

Caribbean

- U.S. to/from Latin America And

The voice traffic projections shown in Table 2.2.4-2 are from

the 1984 Intelsat traffic data base, and are also consistent

with PANAMSAT projections. While traffic is exclusively that

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between earth stations in the Intelsat system, we believe these

numbers are sufficiently 'soft' to include expected growth in

private line traffic. The projected voice traffic also includes

some data.

Table 2.2.4-2

U.S./Latin America And Caribbean Voice Traffic

(Half-Circuit)

1990 1995 2000

13.280 19.424 28.702

The video traffic projections shown in Table 2.2.4.3 are

based on a Satellite Communications Procurement Index developed

by PANAMSAT. and on current traffic. Almost all video traffic

will be TV distribution from major cities to provincial

centjers. Little demand is projected for videoconferencing.

Table 2.2.4-3

U.S./Latin America And Caribbean Video Traffic

(Channels)

1990 1995 2000

Broadcast T.V. 6 11 20

*

Videoconferencing 01 2

TOTAL 6 . 12 22

*

Expressed in Broadcast Quality Video Channels;

1 Broadcast channels = 20 Videoconferencing Channels.

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Ford Aerospace &

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2.2.4.3 Regional Service - Intra Latin America & Caribbean

The voice traffic projections of Table 2.2.4-4 are from the

1984 Intelsat traffic data base, and are also consistent with

PANAMSAT projections. While traffic is exclusively that between

earth stations in the Intelsat system, it is believed that these

numbers are sufficiently 'soft1 to include expected growth in

private line traffic. The voice traffic also includes some data.

Table 2.2.4-4

Intra-Latin America & Caribbean Voice Traffic

(Half-Circuit)

1990 1995 2000

3.048 4.575 6.650

The video traffic projections of Table 2.2.4-5 are based on a

Satellite Communications Procurement Index developed by

PANAMSAT. and on current traffic. Almost all video traffic will

be TV distribution from major cities to provincial centers.

Little demand is seen for videoconferencing.

Table 2.2.4-5

Intra-Latin America & Caribbean Video Traffic

(Channels)

1990 1995 2000

Broadcast T.V. 6 11 20

Videoconferencing* 0 1 2

TOTAL 6 12 22

*Expressed in Broadcast Quality Video Channels;

1 Broadcast channels = 20 Videoconferencing Channels.

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2.2.5 International Traffic Forecast

This section details the voice, video and data traffic

forecast for communications between Region 2 and other regions.

The information is divided into two segments. namely the

Atlantic Ocean Region(AOR) and the Pacific Ocean Region (FOR).

2.2.5.1 Atlantic Ocean Region (AOR)

The Atlantic Ocean Region voice traffic projection of Table

2.2.5-1 is based on the 1984 Intelsat traffic data base. This

covers all trans-Atlantic traffic between North and south

America to Europe and Africa. There are two countervailing

factors which tend offset each other, leaving the Intelsat

projection as the 'best guess1: 1) the positive effect of

competitors to Intelsat in the satellite industry and; 2) the

negative effect of fiber optic cables (TAT-8 and TAT-9).

Table 2.2.5-1

Atlantic Ocean Region Voice Traffic (International)

(Half Circuits)

1990 1995 2000

53.942 77.995 117.630

The Atlantic Ocean Region video traffic projection of Table

2.2.5-2 is based on the current Intelsat leases for

international video. PANAMSAT traffic projections and the Walter

Hinchman Study prepared for Intelsat. The 1983 base figure is

5.5 Intelsat transponders leased for video. High growth is

projected to include both program transfer and videoconferencing

(expressed in equivalent broadcast-quality T.V. channels).

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Table 2.2.5.2

Atlantic Ocean Region Video Traffic

(Channels)

1990 1995 2000

Broadcast T.V. 10 20 30

Videoconferencing* 5 10 30

TOTAL 15 30 60

•Expressed in Broadcast Quality Video Channels;

1 Broadcast channels = 20 Videoconferencing Channels.

The three elements of data traffic considered are: current

traffic carried by ORC's(i.e. telex, telegraph & low speed

data); current data traffic carried over voice-grade circuits;

and IBS type traffic. The forecast of Atlantic Ocean Region

voice traffic shown in Table 2.2.5-3 is based on estimates of

International Business Services (IBS) from Intelsat plus

projections of growth for gateway Intelsat data traffic. It is

assumed that 1 voice grade channel = 3 telex bearers; 1 telex

bearer = 24 telex channels; and 1 voice grade channel = 64 kb/s.

Table 2.2.5-3

Atlantic Ocean Region Data Traffic

(In Mb/s)

1990 1995 2000

190 410 880

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2.2.5.2 Pacific Ocean Region (FOR)

The Pacific Ocean Region voice traffic projection shown in

Table 2.2.5-4 is based on the 1984 Intelsat traffic data base

(Ref. 9). This forecast covers all trans-Pacific traffic

between Canada, the U.S.. and Mexico to Eastern Asia and Oceana.

Table 2.2.5-4

Pacific Ocean Region Voice Traffic

(Half Circuits)

1990 1995 2000

13.672 22.132 37.186

The Pacific Ocean Region video traffic projection shown in

Table 2.2.5-5 is based on Intelsat's current video channel

leases (5.5). The traffic is largely composed of U.S. -

Australia and U.S.- Japan TV distribution and videoconferencing.

The videoconferencing component of demand is expressed in

equivalent broadcast quality TV channels.

Table 2.2.5-5

Pacific Ocean Region Video Traffic

(Channels)

1985 1990 2000

Broadcast T.V. 6 10 15

Videoconferencing* 0 2 10

TOTAL 6 12 25

* Expressed in Broadcast Quality Video Channels;

1 Broadcast Channel = 20 Videoconferencing Channels.

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The Pacific Ocean Region data traffic projection shown in

Table 2.2.5-6 is based on the estimate of demand cited by

International Record Carrier's in support of Pacific Ocean fiber

optic cable request to the F.C.C. There is currently no IBS

forecast for the Pacific Ocean Region. The P.O.R. voice traffic

is estimated to be approximately 10% of Atlantic Ocean Region

(A.O.R) voice traffic for 1990 and 20% by 2000.

Table 2.2.5-6

Pacific Ocean Region Data Traffic

(In Mb/s)

1990 2000

41 176

2.2.6 Maritime Services Traffic Forecast

The maritime traffic forecast of voice and data for Canada

and Latin America/Caribbean as shown in Table 2.2.6-1 is based

on the current Inmarsat traffic matrix, and forecasts for the

second generation Inmarsat system. The "Nominal" Inmarsat

traffic estimate is used as the traffic base. Traffic is split

in following ways: 90% voice. 10% data; 80% A.O.R.. 20% P.O.R.

Development of significantly cheaper earth stations and more

varied service offerings may spur maritime growth beyond

estimates shown.

Table 2.2.6-1

Maritime Traffic From Canada And Latin America/Caribbean

A.O.R. & P.O.R.

(In voice-grade circuits)

1985 1990 1995 2000

72 147 245 307

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2.2.7 Future Growth for Traffic Forecast to Year 2008

The growth in traffic for fixed satellite services is

expected to follow the growth rates projected in Table 2.2.7-1.

The growth rate for the decade of year 1990 to year 2000 is

compared to that of the succeeding decade for each segment of

FSS demand (voice, video and data) as well as for different

geographic areas.

Table 2.2.7-1.

Projected FSS Growth From Year 2000 To 2008

REGION

Domestic

1990-2000

GROWTH RATE PER YEAR(%)

Voice Video Data

2000-2008

GROWTH RATE PER YEAR (%)

Voice Video Data

a)U.S. 14

b)Canada 7.5

c)Latin America.

Caribbean.&

South America 8

15

7

10.5

6

11

6

REGIONAL

a)Canada-U.S. 7

b)U.S.-Latin

America 12

c)Intra Latin

America 12

10 7.5

14

14

12

12

14

14

INTERNATIONAL

a)A.O.R.

b)P.O.R.

8

10.5

15

8

8

16

8

10.5

11

8

6

6

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Ford Aerospace &

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The total projected traffic demand for year 2008 for each of

the types of services is shown in Table 2.2.7-2. The derivation

of the video conferencing demand for trunking applications in

detailed in Table 2.2.7-3.

Table 2.2.7-2

Proiected Traffic for year 2008 by Type of Service

Type

— Voice Trunking

— Digital (60%)

— Analog (40%)

— Voice CPS

— Data Trunking

— Data CPS

— Video Conf. Trunking

— Video Conf. CPS

— Broadcast Video

Year 2008 Totals

9090

6060

78

5336

39907

37800

(1576

2131

537

10 HVC

103 HVC

10 HVC

Mb/s

Mb/s

Mb/s or

103 HVC)

Mb/s

Channels

2.3 TRAFFIC DISTRIBUTION MODELS

2.3.1 Approach

During the data base development, distribution models for the

CONUS traffic and the Intelsat traffic were acquired from NASA

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Ford Aerospace &

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Table 2.2.7-3

Derivation of Video Conferencing Demand (Trunkinq)

FULL

30

76

LIMITED

184

5776

SLOW

-

1748

1-WAY

2-WAY

TOTAL 106 + 5960 + 1748 = 7814 CHANNELS

o THROUGHOUT: 3 (FULL). 36 (LIMITED). 900 (SLOW )

(36 MHz )

o AVERAGE REQUIREMENT PER CHANNEL

81 MB/S (106 5960 1748)

A •*• "*"

 = e. • 1 rlD/D

7814 3 36 900

*i^ '

o TOTAL 2008 REQUIREMENT

7814 X 2.1 X 1.118 - 37800 MB/S

and Intelsat respectively. It was also necessary to generate

models for Canada. Mexico and Brazil since the projected 2008

demand exceeded the 4x reuse from C and Ku-band application.

Use of population distribution data and domestic phone system

distribution data were used to make a first cut approximations

at the distribution matrix.

Section 2.2 discussed total traffic forecasts in several

categories. However, in designing a payload - especially the

beam coverages - the distribution of the traffic must also be

considered. First, there is the well-known skewness of U.S.

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Ford Aerospace &

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traffic to the East; high frequency reuse in this area is a

major objective of any payload design. The point-to-point

nature of the distribution is important in those channels

operating with analog modulation, and can also be used to

optimize designs using SS/TDMA.

Distribution models were not developed for all traffic

considered. As an example, broadcast video does not require a

distribution. Domestic coverage for several South American

countries - e.g.. Columbia - could be provided by a single beam;

hence distribution characteristics were not relevant.

The following subsections describe the distribution models

used in this study.

2.3.2 NASA FSS Model

A tape containing data on a 316x316 matrix, representing the

distribution traffic between 316 selected SMSAs. was provided by

NASA at the beginning of the study The distribution was used

for all U.S. domestic point-to-point requirements. Section

4.2.3.1.1 describes how the tape was processed in various ways

for use in • satellite loading programs. In particular, all

traffic requirements between SMSAs whose distance was less than

400 miles were deleted from the original tape to obtain

satellite addressable traffic.

2.3.3 Intelsat FSS Model

The Intelsat distribution model reflected actual satellite

addressed traffic from gateway station to gateway station. This

matrix then was used to generate intra Region 2 traffic as well

as Region 2 to AOR and Region 2 to FOR traffic matrices for

application to the payload concepts discussed in Section 4.

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Ford Aerospace &

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2.3.4 Other Distribution Models

In three cases distribution models were developed as part of

this study because the total year 2008 requirements of Section

2.2.7 indicated frequency reuse would be necessary to meet the

demand in Canada. Mexico, and Brazil.

The basic approach used was to break each country into

regions, such as provinces, and to use population estimates to

obtain a distribution as follows:

Let P. be the population the i region, and a. . be the

proportion of the total traffic between region i and j. Then:

PjP}

ot>—

There were two modifications to this basic approach. First,

for Canada only, a "proportionality matrix" was developed which

adjusted the a. . to reflect a "400 mile rule" (see Section

2.3.2). For example. New Brunswick is less than 400 miles in

total extent, so all traffic from that province to itself was

deleted. The modified formula is:

tijPiPj

'.;"

k I

where t.. is the proportionality factor. The second

adjustment was to inflate traffic to/from national capitals, or

the regions in which they lie. by a factor of 10.

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Ford Aerospace &

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Tables 2.3-1 thru 2.3-4 indicate the various values used to

derive the distribution matrices. The matrices (in terms of

total demand) are contained in Appendix C. For Mexico, the

fraction of population was estimated to be that shown in Table

2.3-1.

Table 2.3-3

Canada-Proportionality Matrix

Aioe A 1 K A r+ a r ta

Metni LOua

New Brun.

Mai-yf

IMcwL .

IMn I ct£ .

Nova Scotia

Cln t- 1

Ont 2

P.E. Is.

Que 1

Que 2

Saskwan.

Yukon

' 111011011 0

111011011 0

1111111 . 9 . 9 1

111011011 0

1 1 1 .51 1 1 0 11

111111111 1

.81.4 1 1 11 1 1 1

111111111 1

.51 1 1

111 1

011 L L L1

111 1

111 1

0 .7 1 1

.7 .9 1 1

1 1 .2 1

1 11 1

2-40
Ford Aerospace &

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Table 2.3-1

Proportion Of Population By Region - Mexico

Area

North Region

Central Region

South Region

of Population

20%

50%

30%

Table 2.3-2

Canada - Adjusted Population

Province/Area

Alberta

British Columbia

Manitoba

New Brunswick

Newfoundland

NW Territories

Nova Scotia

Ontario 1

Ontario 2

Prince Edward IS

Quebec 1

Quebec 2

Saskatchewen

Yukon

Population(K)

1627

2184

988

635

522

35

789

8880

1540

112

4822

1206

926

18

CD

(2)

(3)

(4)

(1)

(2)

(3)

(4)

7703 X .8 + 302

7703 X .2

6028 X .8

6028 X .2

X 9

* 302 K = population of Ottawa; the factor of 9 provides the

inflation mentioned in section 2.3.4 for capitals

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Table 2.3-4

Brazil-Adjusted Population

State Population (x 1000)

Acre

Alagoas

Amapa

Amazonas

Bahia

Ceara'

Distrito Federal

Espirito Sauto

Guias

Guanabara

Maranhao

Mato Grosso

Minas Gerais

Pura

Paralba

Purana

Pernarabuco

Piaui

Rio de Janeiro

Rio Graude de Worte

Rio Graude de Sul

Rondonia

Roraima

Santa Catarina

Sao Paulo

Sergipe

160

1271

69

721

5991

3338

1410*

1189

3307

1955

2492

910

9799

1551

2018

4278

4137-

1263

3403

1157

5449

71

29

2147

12975

760

*141K = population of Federal District; population

in the Table is inflated as mentioned in section

2.3.4.

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2.4 SPACE AND TERRESTRIAL SUPPLY FORECAST

2.4.1 Overview

A main subtask of Task 1 was to estimate the extent of both

space and terrestrial plant in place for the time period of

interest. This effort was largely conducted by Satellite

Systems Engineering. Inc. (SSE).

The main objectives of this subtask were threefold:

1. To assess the demand for positions on the orbital arc

in the late 1990's. This serves as the basis for evaluating the

motivation behind a better utilization of the arc (through the

introduction of multiple frequency reuses and scanning spot beam

coverage).

2. To offer a snapshot of what kinds of commercial

satellite services are likely to be offered in the late 1990's

without the existence of a larger space platform, thus giving

some indication of the satellite operator's perception of

demand; and

3. To give a preliminary estimate of the extent of

displacement if a large space station became operable during

this timeframe.

The space segment estimates include number of satellites,

frequency bands utilized by each, capacities, and orbital

location.

An example model of satellite supply based on current and

planned U.S. domestic satellite systems is shown in Tables 2.4-1

and 2.4-2. The tables list the name of the system, the

frequency bands used, the number of satellites in orbit and the

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OF POOR QUALITY

Table 2.4-1

U.S. Domestic FSS Systems Satellite Supply

Sate! 1 ita

Systems

Advanced Bus.

Communication

A las com

American

Satellite

Cablesat

General

Comstar

Digital

Telesat

Equatorial

Fed. Express

Fordsat

Galaxy

G-Star

Martin Marietta

National

Exchange

Rainbow

RCA Satcom

SBS

Spacenet

Tel star

USSS1

Westar

9

Frequency

Band

:<u

C

C.Ku

C.Xu.Ka

C

C

Ku

C

Ku

C

Ku

C,Ku

C

Ku

Ku

Ku

C

Ku

Ku

C

Ku

Ku

Ku

C,Ku

C

Ku

C

C

Ku

TOTALS

Number of

1985

0

1

1

0

T

2

0

0

0

0

0

0

3

0

2

0

0

0

0

4

2

4

0

2

3

2

1

4

_0

32;

2-44

Satall

1990

2

2

3

1

2

0

3

7

1

2

2

3

4

3

3

2

2

4

4

7

3

1

5

3

4

4

0

7

_3

31

itas in Orbi

1995

2

2

3

1

2

0

3

1

2

2

2

3

4 -

3

3

2

2

4

4

7

3

1

5

3

4

4

0

7

_3

32

t Per

2000

2

2

0

. 3

2

0

3

1

2

2

2

3

4

3 '

3

2

2

4

4

7

3

1

5

3

4

4

0

7

3

31
ToKct^) Ford Aerospace &

Communications Corporation

Table 2.4-2

U.S. Domestic FSS Systems Transponder Supply

Number of Number of Availabl e Transponders

Satellite Frequency 26 MHz

Systems Band Transponders

Advanced

Bus. Communic.

Alascom

American

Satellite

Cablesat General

Comstar

D.igital Telesat

Equatorial

Fed. Express

Fordsat

Galaxy

G-Star

Martin Marietta

Nat I. Exchange

Rainbow

RCA Satcom

S3S

Spacenet

Tel star

USSS1 .

Westar

Ku

C

C,Ku

C.Ku.Ka

C

C

Ku

C

Ku

C

Ku

C,Ku

C

Ku

Ku

Ku

C

Ku

Ku

C

Ku

Ku

Ku

C,Ku

C

Ku

C

C

Ku

24

24

36

48

24

24

24

24

24

24

48

48

24

24

24

24

24

24

24

24

24

12

24

36

24

24

12

24

24

1985

0

24

. 36

0

24

48

0

0

0

0

0

0

72

0

48

0

0

0

0

96

48

48

0

72

72

48

12

96

0

3y

1990

48

48

108

48

48

0

72

24

24

48

96

144

96

. 72

72

48

48

96

96

168

72

12

120

108

96

96

0

163

•72

Year

1995

48

48

108

48

. 48

0

72

24

48

48

96

144

96

72

72

48

. 48

96

96

168

72

12

120

108

96

96

0

163

72

2000

48

48

108

144

48

0

72

24

48

48

96

144

96

72

72

48

48

96

96

168

72

12

120

108

96

96

0

163

72

744 2143 172 2268

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Ford Aerospace &

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number of available transponders for 5-year intervals up to the

year 2000. The determination of equivalent transponders is

based on a frequency allotment of 500 MHz bandwidth to an

orbital location in C-band or Ku-band. Dual frequency reuse for

CONUS coverage results in a maximum of 24 equivalent

transponders for a C-band or Ku-band satellite and 48 equivalent

transponders for a hybrid satellite. Spot beam coverage is not

considered. These tables assume one-for-one replacement after

the end of the expected design life, with no new systems being

added.

The question of orbital locations is largely dependent on the

results of Space WARC '85 and how soon the FCC will phase in

2 spacing. Working Group A-2 of the FCC Advisory Committee

preparing for the Space WARC has projected that the saturation

point of the U.S. portion of the C-band and Ku-band arc is

between 48 and 65 satellites, depending on how quickly improved

antennas are introduced on the ground. This estimate assumes

that three satellite slots would be kept vacant as "guard band"

slots to allow for possible adjustments in some orbit locations

due to inhoroogeneities between certain satellite systems or

types of satellite services. There is obviously a major

discrepancy between the number of satellites being proposed and

the capacity of the orbital arc.

It is difficult to predict the types of traffic carried on

the satellites during this time period, since satellite systems

are usually designed before any customer has been signed.

The terrestrial segment estimates include numbers of earth

stations serving the space segment, range of sizes and types of

earth stations, and frequency bands utilized.

Information was obtained from FCC applications and

statistics, direct contacts with the major terrestrial

2-46
Ford Aerospace &

Communications Corporation

transmission system owners, and a literature search. There is a

large body of material in the CCIR and CCITT area on this topic,

with special reference to the introduction of the Integrated

Services Digital Network (ISDN).

The quantity, range of sizes and types, and frequency bands

utilized by the earth stations during this period are all

directly related to the estimate of space segments in place.

SSE keeps an updated data base of all FCC licensed earth

stations by size and location. as well as an educated

"guesstimate" of the approximate size and locations of all

unlicensed earth stations (ie. the nearly 200.000 "backyard

TVROs"). This data base was expanded to include the inputs from

FCC applications for future satellite systems, interviews with

industry analysts, and an extensive literature search.

2.4.2 Estimate of Satellite Transponder Supply

The supply estimates in this section were prepared by

Satellite Systems Engineering. Inc. (SSE).

The following types of satellites were considered: U.S.

Fixed Satellite Service (FSS). Direct Broadcast Satellites (DBS)

and Mobile Satellite. Non-U.S. Region 2 FSS. Atlantic Ocean

Region (A.O.R.) and Pacific Ocean Region (P.O.R.) FSS.

The SSE transponder supply model is based on the actual and

planned supply of satellites. For example. in the United

States, there are currently 23 fixed communications satellites

in orbit. Many more are planned, and filings to the FCC

indicate planned launch dates.

The SSE model provides the number of satellites and

transponders in orbit now, and low, high and best estimates for

corresponding numbers of satellites in orbit in 1990 and 1995.

2-47
Ford Aerospace &

Communications Corporation

For fixed service satellites, a 36-MHz transponder is used as a

reference transponder. For DBS and mobile service satellites,

the number of active channels planned is used.

The low estimates are based on satellites actually operational

in space, satellites under construction. or authorized

satellites. The high estimates are based on all known planned

satellites. In general, the amount of planned systems will

reflect a perceived demand that may not be realized in the short

term. It appears from available FCC data on transponder loading

that the market for communications satellites in the U.S. is

over-saturated. in the sense that more transponders are

available in orbit than are being used (even taking into account

sparing philosophies).

The best guess estimates have been guided by these

considerations. An attempt has been made to take into account

the shift to higher frequencies with frequency reuse and the

resulting changes effected in; numbers of transponders by

successive generations of satellites. An optimistic long-term

demand is projected for U.S. DBS and mobile satellites, although

financial and regulatory difficulties may be severe. The

forecast is optimistic about the development of satellite

communications over the Atlantic Ocean; however, it is more

reserved about the Pacific and Latin American markets.

A summary of the U.S. domestic satellite supply is given in

Table 2.4-3 and a summary of the non-U.S. domestic supply is

given in Table 2.4-4.

The supply projections are taken from known planned satellite

systems worldwide. Since it is highly unlikely that all planned

systems will be built, a probability factor was applied to each

system reflecting various considerations, including financial,

market base, regulatory, and/or institutional factors.

2-48
Ford Aerospace &

Communications Corporation

Table 2.4-3

Forecast Of U.S. Domestic Satellite Transponder Supply

FSS' LOW

BEST

HIGH

1990

636

1048

2364

1995

804

1430

2280

2000

****

1951*****

 

DBS' LOW

BEST

HIGH

0

10

222

0

42

222

0

42

222

MOBILE/** * LOW

RADIO- BEST

NAVIGATION HIGH

0

3

19

0

6

19

**

***

 

** ***

In equivalent 36 MHz transponders

In broadcast quality channels

In 4 MHz transponders

Not estimated

Assumes constant growth from 1995

0

6

21

The key findings reached from the supply analysis are as

follows:

o U.S. Domestic FSS Supply roughly tracks demand.

o Non-U.S. Supply is considerably more than demand.

o DBS Supply roughly tracks demand.

o Mobile Supply insufficient to handle demand in U.S. (as

currently applied for); supply tracks with demand in

Canada,

o Maritime Supply exceeds demand.

Additional detail on the estimate of U.S. domestic satellite

transponder supply is given in Table 2.4-5. and detail on the

non-U.S. domestic supply is given in Table 2.4-6. The projected

launch dates and configurations of Region 2 Commercial

Communications Satellites over the period of 1984 to 2010 are

shown in Figure 2.4-1.

2-49
Ford Aerospace &

Communications Corporation

Table 2.4-4

Forecast Of Non-U.S. Domestic Satellite Transponder Supply

(Includes Canada, Latin American, Caribbean.

Atlantic Ocean Region and Pacific Ocean Region)

1990 1995 2000

FSS* LOW 210 276

BEST 384 574 574

HIGH 1100 1650

DBS* LOW 0 0 0

BEST 0 12 12

HIGH 6 24 24

Mobile*** LO W 00 0

1

1

Maritime LOW l 2 2

BEST 3 3 3

HIGH 54 4

* In equivalent 36 MHz transponders

** In broadcast quality channels

*** In 4 MHz transponders

**** In equivalent 2nd generation Inmarsat

transponders

2.4.3 Terrestrial Terminal Supply

The forecast of terrestrial terminal supply for satellite

communications is divided into: a) FSS and DBS Service (for

U.S. and hon-U.S. segments) and b) Mobile Services. Additional

detail on the quantities, characteristics; and distribution of

the current population of earth stations in the United States is

given in Appendix E-2.

2-50

LOW

BEST

HIGH

0

1

1

0

1

1
Ford Aerospace &

Communications Corporation

Table 2.4-5

Estimate. Of U.S. Domestic Satellite Supply And Transponders

System Current t Sat./Tr. in

orbit 1984

Freq.

Est. *

Sat./Tr. in

orbit 1990

low high best

Est. *

Sat./Tr. in

orbit 1995

low high best

U.S. FSS

AURORA

AMERICAN

CABLESAT

COLOMBIA

COMSTAR

COMSTAR

DCBS

DIGISAT

EOUASTAR

FEDNET

FORDSAT

GALAXY

GALAXY

GALAXY

GSTAR

MARTIN

SATCOM

SATCOM

SBS

SPACENET

SPOTNET

TELSTAR

WESTAR

WESTAR

TOTALS:

1/24

inVF

lf\

i'

ft/i

/.P..

4/4

$

VA*

23/508

C

C,Ku/Ka

C

C

C

KU

Ku.Ka

C,KU

C

Ku

C,KU

KU

Ka

Ku

Ku

C

KU

Ku

C,KU

C,KU

C

C

Ku

1/24

wo/o

o/o

o/Q

84° o/o

o/o

#

3/?2 2/48

2/4

2/48

2/96

9/216

3/72

m v.

M

I'M

I'/l*

111

1X24

m

0/0

S'

^?

0/0

0/0

44 9/216

3/72

5/120

3/72

7/170

3/72

26/636 86/2364 40/1048 29/804 77/2280 51/1430

U.S. DBS

DBSC

DVSS

RCA

STC

USSB

HUGHES

NCN

SDT

SSS

NEX

ACC

8/"8

8/8

8fl 8^8

8^8

0/0

DBS

DBS

DBS

DBS

DBS

DBS

DBS

DBS

DBS

DBS

DBS

8/8

0/0

8/8

0/0

0/0

0/0

0/0

0/0

0/0

1/1°

¥A2

mm2/12

2/32

2/12

1/10

0/0

0/0

0/0

0/0

0/0

0/0

0/0

0/0

0/0

0/0

0/0

0/0

0/0

0/0

0/0

0/0

0/0

0/0

o/o

0/0

0/0

i^i0

i/'i2

2/32

2/12

2/32

2/12

2/32

2/12

^4°

Wo/o

1/16

0/0

0/0

0/0

0/0

0/0

TOTALS: 0/0 0/0 24/222 1/10 0/0 24/222 3/42

U.S. MOBILE/RADIOHAVTCATION

MOBILSAT** 0/0

SKYLINK * 0/0

OMNINET ** 0/0

GEOSTAR * 0/0

UHF,L,Ku 0/0

UHF 0/0

UHF,L,KU 0/0

L 0/0

3/1

\'A

0/0

0/0

0/0

0/0

0/0

0/0

0/0

0/0

2/6

#4/34

0/0

0/0

1/3

2/2

TOTALS: 0/0 . 0/0 11/19 0/0 0/0 11/19

* 5 MHz/satellite at UHF; 10 MHz/satellite at L-band

5 MHz/satellite at UHF **

3/5

2-51
Ford Aerospace &

Communications Corporation

• Table 2.4-6

Estimate Of Non-U.S. Satellite Supply And Transponders

System Current #

Sat./Tr. in

orbit 1984

Freq.

Est. *

Sat,/Tr. in

orbit 1990

low high best

Est. *

Sat./Tr. in

orbit 1995

low high best

NOH-D. S. REGION 2 FSS

ANIK 2/48 C

ANIK 2/48 Ku

ARGENTINA 0/0 C

ASETA 0/0 C MORELOS 0/0 C, Ku

PANAMSAT 0/0 C,Ku

SATCOL 0/0 C

SBTS 0/0 C

TOTALS: 4/96

INTERNATIONAL A.O.R. FSS

CYGNDS 0/0 KU

INT. IV* 3/26 C

INT. V* 4/144 C,KU

INT. VI* 0/0 C,KU

INT. VII* 0/0 C,Ku,Ka

INT. Y/Z* 0/0 Ku

ISI 0/0 KU

ORION 0/0 Ku

DNISAT 0/0 C

TOTALS: 7/170

INTERNATIONAL P. O.K. FSS

INT. IV* 1/20 C

INT.V* 0/0 C,Ku

INT. VI* 0/0 C,Ku

PACIFIC 0/0 C

TOTALS: 1/20

NON-0. S. DBS

CAN-DBS 0/0 DBS

S. AM. -DBS 0/0 DBS

TOTALS: 0/0

NON-US MOBILE/MARITIME

INMARSAT **

-MARECS 1/1 C,L

-MCS 4/4 C, L -2ND GEN 0/0 C,L

M-SAT *** 0/0 UHF

TOTALS: 5/5

2/48

0/0

0/0

0/0

o/o

0/0

0/0

4/96

01

o or-ooooov

o

ooroooooor-i 4/78

0/0

1/36

0/0

0/0

1/36

0/0

0/0

0/0

4^4

0/0

5/5

2/48

3/72

2^72

2/48

2/48

16/384

11°

m

2/12

18/548

0/0

5/168

1/6

0/0

1/6

y/l

\

f

/\

10/10

2/48

2/48

1^6

0/0

1/24

6/156

0/0

3%

if

6/192

0/0

1/36

0/0

0/0

1/36

0/0

0/0

0/0

\ti

1/1

8/8

2/48

0/0

0/0

0/0

4/96 oooootooo

o

oooootooo

o

Ot

2/96

$f

2/84

0/0

0/0

0/0

0/^8

V/l

2/2

$!!

ffi§

2/48

16/408

2/48

rfii

5/120

0/0

20/1076

%k

5/166

2/12

2/12

4/24

0/0

o/o

1/1

5/5

1/24

1/12

o/o72

y/it

12/300 OMOIOOOJOO

O

OtOO**OMOO

O

tO C

O •£>

lU

6/214

Wy,®

2/60

v/\

2/12

8^8 v\

4/4

* Satellite/Transponder Supply numbers refer only to operational

satellites.

** MARECS and MCS - 30 channels/satellite

2nd_year - 150 channels/satellite

*** MSAT^- 5 MHz/satellite

2-52
Ford Aerospace &

Communications Corporation

9'G'NAL

POOR

Figure 2.4-1

Projected Region 2 Commercial Communications Satellite In Orbit 1984-2010

—J end of life,

nned lainch date

rrently in orbit

based on design life SGDRCE: SAT£U.HE SXS7B6 DIGEST, Sumer 1984 edition

a^Ku-Band Ka-Ka-Band_I^IcBand^S;S-Band P-Probabil ityof Implementation (SSE estimate - percentage)

0-12- 12 C-Band Transponders m> Direct Broadcast

1984 1385 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 200S 2006 2007 2008 2009 2010

•e SOt-2 D3S-6

KuSii24^?5

-e SATQOH-K5 Ku-16 P-50

e BU3HE9-B2 DB9-16 P-25

WESTAR-IX 0-24 P-75

-e WESTBR-K3 - .6 P-25

e DSftT-4 Ku-20 P^IO

SKTOQM-K4 Ku-1•6.

HIEBES-K2 Ka-32

HUGHES-K1 Ka-32 . __

HIEHES-B1 D3S-16 P-25

-'ISAT-1B C-24 P-10

iR-K3 Ku-16 P-25

0-24 Ku-15 Ka-3 P-50

2 C-24 P-50

-e SSS-:

-e JJSKf-3 KU-:

-e TELSTAR-30 . ._

-e GBS-fR Ku-14 P-75

-e PAWMSAT-2 0-24 P-10

-e MVRTIN-2 Ku-16 P-50

-e MMTIN-1 Ku-16 P-5

-e GALAXY-K3 Ku-16 P-

-e FCRD6AT- _._ '33 C-2 0-244 Ku-24

AT-J C-24 Ku-24

JO-1 0-24 Ku-24

;-2 Ku-48 P-25

-e FEDEX-1 Ku-48 P-25

-e mORKKIAL-2 C-24 P-50

-e DIGISAT^lA Ku-24 P-10

-e CDHSTAR-K2 Ku-16

DCB9-

-e ARGENTINA-2 0-2.

-e AJGENTINA-1 0-24

e DCMT

-« NC»-2 DB

-e NCN-1 IB&-6 P-

-6 DS£B-2 D3S-6 P-

-e SO-1 IB»-6 P-5

-e NEX-1 tBS-16 P-10

"^2 D39-6 P-5

~ IB9-4 P-20

2-53
Ford Aerospace &

Communications Corporation

., -vv.q 5;-'

,/' ^s/"- • -

ORIGINAL PAGE IS

POOR 6UALITY

Figure 2.4-1 (Continued)

e SATQOH-K3 Ku-16 P-50

« RAIN3CW-2 Ku-20 P-25

RADBCW-I Ku-20 P-25

GSBW-3 Ku-16 P-50

« CGLUWIft-2 C-2

c CQUneiA-1 0-2

e ASO-3 C-1B

e ACC-1 IBS-6 Pe ffiO-2 Ku-20

IBS-4 P-20

e SKXLINK-2 UHFM P-10

e KBILSKP-I Ii-l Ku-1 DHP-1 P-25

e DSAT-1 Ku-20 P-50

ET-4 0-18 Ku-6 P-50

« SAK5M-VI C-24 MS

~ Ku-14 P-1

• 24 P-50

e GRAHiSAT-1 EB9-2 P=0

e WISTAR-VI1 0-24 P-100

6 mSTAR-303 C-24 P-100

e SBkOMEM C-18 Ku-6 P-100

B SKTOCH-K-2 Ku-16 Pe SATOOH-K-I Ku-16 Pe MCREXOS-2 C-18 Ku-4 P-75

e ICRELOS-I 0-18 Ku-4 Pe GSTAfi-2 Ku-16 P-100

« CRBLESAT-1 C-24 P-25

e flSO-1 0-18 Ku-6 P-100

e WJIK-C — 1 Ku-16 P-100

6 ffiTS- 5r- ? 0-2—4 P-10 -lo0

« SBTS-I 0-24 P-100

e raSTAft-3Q2 C-24 P-100

-18 Ku-6 P-100

18

e GWAXy-3 C-24

e MlIK D-2 0-24 Pe TELSrAJMOl C-24 P-10

SATOQH-IIR 0-24 P-100

e SATCDH-m 0-24 P-100

eGALAJff-2 "

e GAUUQf-1

WESXftR-V 0-2

e HESTAH-IV C-:

o-

« SATOQM-IV "

e as-i

WESTNt-IIl 0-

CGMSXAR-III 0-24 P-100

1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010

2-54
Ford Aerospace &

Communications Corporation

2.4.3.1 Terminals in Support of FSS and DBS Service

United States Located. A forecast of the earth station

population within the United States for FSS and DBS service is

given in Table 2.4-7.

Table 2.4-7

Earth Station Population Within The U.S.

(FSS And DBS Service)

Receive Only

TVRO

Audio/Data RO

Licensed Unlicensed Total

5.707

710

506.793

5.890

512.500

6.600

Transmit/Receive

Carrier

(i.e., shared use)

575 575

Dedicated

(on Premise)

615 615

Other

98 98

Totals 7.705 512.683 520.388

* It is to be noted that about 500.000 of the Receive Only TVRO

terminals are unlicensed backyard installation and that this

value is a very approximate estimate.

Data on the licensed earth stations comes from the Facilities

and Services Division of the FCC's Common Carrier Bureau, July

1984. Data on the unlicensed earth stations comes from a

2-55
Ford Aerospace &

Communications Corporation

variety of sources, including in-house data at SSE. contracts

with satellite system operators and resellers, trade

associations, industry publications and consultants, and users.

The number of unlicensed TVRO's are approximate at best as this

industry is very loosely structured and growing fast. All

transmitting earth stations are licensed. 90% of all T/R's

operating in Alaska are owned by Alascom and are shared usage

carriers. Very few T/R's in either Alaska or Hawaii are for

private, dedicated use.

The quantity of terminals projected for the future will be

very dependent upon the growth of competitive fiber optic cable

systems.

In the past few years fiber optic technology has experienced

several major breakthroughs in capability. practicality of

implementation, and costs. Over a dozen national and regional

fiber networks are currently being implemented in the U.S. and

it is possible that 80.000 route miles will be installed and

operational by the late 1980's. This represents about 30% of

the current long-haul plant in place.

Key parameters of current fiber optic network planning includes:

o 3-5 Nationwide Networks

— AT&T, MCI. Sprint, etc.

— 565 MB/s/fiber pairs

— 5-20 fiber pairs/cable

-- 7,000 - 20,000 route miles for each network

o Many Regional Networks

-- Lightnet - East

-- Microtel - East

— Electra - Central

— Litel - Central

— LDX - Central

-- Fibertrak - West

-- United Telecom - Central/West

2-56
1985

20

100

10.000

1990

30

200

25.000

2000

50

1000

25.000

Ford Aerospace &

Communications Corporation

Non-U.S. Located. A forecast of the FSS and DBS earth

station population within Canada is given in Table 2.4-8. The

large T/R corresponds to antenna dish sizes in excess of 10

meters; the medium T/R are less than 10 meters; the Receive Only

(RO) are greater than 2 meters; and the DBS are less than 2

meters.

Table 2.4-8

FSS And DBS Terminals Within Canada

Large T/R

Medium T/R

RO

A forecast of the FSS and DBS Terminals within Latin America,

South America, and the Caribbean is given in Table 2.4-9. The

large T/R stations represent the Intelsat gateway stations, and

the medium T/R stations represent domestic and intra-regional

stations.

Table 2.4-9

Terminals Within Latin America. South America. And The Caribbean

(FSS And DBS)

1985 1990 2000

Large T/R 45 50 75

Medium T/R 70 200 1000

RO 50 2000 - 5000 50.000

DBS 0 0 100.000

2-57
Ford Aerospace &

Communications Corporation

2.4.3.2 Terminals in Support of Mobile Service

The forecast of earth terminals in support of U.S. and

non-U.S. mobile services is given in Table 2.4-10.

Table 2.4-10

Terminals Used For Mobile Services

Year 1990 Year 2000

U.S. Canada U.S. Canada

Voice Users 45.000 2.000 180.000 20.000

Data Users 180.000 6.000 1.440.000 60.000

TOTAL 225.000 8.000 1.620.000 80.000

For the United States, it is expected that by 1990 there will

be one mobile satellite system in place, with a total of 2

"transponders" of 15 MHz each (probably at L-band with spatial

diversity and dual polarization). It is projected that the

system will be used at 50% capacity, with a typical growth

curve. One channel will serve 30 voice users, using loading

statistics as stated by Omninet and Mobilsat. One channel will

serve 120 data users, assuming BPSK Aloha modulation of 240 b/s

messages. Current market estimates suggest the system will be

equally shared by voice and data. The 15 MHz bandwidth will

serve:

1500 channels x 30 voice users/ channel = 45.000 voice users

and

1500 channels x 120 data users/channel = 180.000 data users.

2-58
Ford Aerospace &

Communications Corporation

By the year 2000. it is expected that two mobile satellite

systems will be in place, with a total of 8 "transponders" of 15

MHz each (some combination of L-band and UHF-band. with multiple

spatial diversity and dual polarization). It is forecast that

the year 2000 system will be used at 50% capacity. Thus, there

will be a total of 60 MHz of capacity in use.

Using the previously described methodology, it is expected

that 60 MHz would serve 180,000 voice users and 720.000 data

users. However, it is predicted that QPSK will be commonly used t*.

for data by 1995 - 2000 (the voice bandwidth of 5 KHz is already

at the edge of the state-of-the-art, and hence further bandwidth

efficiency is not expected), thus doubling the number of expected

data users. Thus, the 60 MHz bandwidth will serve 180.000 voice

users and 1.44 million data users.

The Canadian estimate for year 1990 and year 2000 is based on

the Phase B market survey done for Telesat Canada.

Table 2.4-10

Terminals Used For Mobile Services

Year 1990 Year 2000

U.S. Canada U.S. Canada

Voice Users 45.000 2,000 180.000 20.000

Data Users 180.000 6.000 1.440.000 60.000

TOTAL 225.000 8.000 1.620.000 80.000

2-59
ford Aerospace &

Communications Corporation

2.5 CONSTRAINTS. SELECTION CRITERIA. AND OTHER CONSIDERATIONS

2.5.1 Study and Task Constraints

Several guidelines and constraints were imposed by the SOW

and several others were added by Ford Aerospace during the study

in order to limit the scope of this study. These limitation

included:

General Guidelines: The study was to use payload configurations

which were based on utilization of 1998 operational technology.

No in-orbit payload assembly was to be required and a minimum

system lifetime of ten years was to be feasible. In addition, a

conformance to anticipated regulatory requirements was to be

accommodated.

Other general guidelines included the accommodation of

communications payloads only, and a rigid spacecraft antenna

configuration was to be incorporated for the baseline FSS and

DBS configurations. The system must be economically feasible,

must be based on demonstrated needs, and must accommodate

user/operator requirements.

Launch Concepts: The payload configurations and characteristics

were to be subject to constraints imposed by various

spacecraft/transportation system/space operations capabilities.

These constraints on the payload are in terms of permissable

weight/power volume/lifetime envelopes. Two sets of envelopes

were to be considered initially:

Launch Concept 1: Up to a maximum single shuttle launch of

combined spacecraft and upper stage with a spacecraft

weight of up to 12.000 pounds.

Launch Concept 2: Allows a separate spacecraft (without

upper stage) of size and weight up to a full shuttle launch

capability (65.000 pounds).

2-60
Ford Aerospace &

Communications Corporation

Communications Service Baseline Requirements: The baseline

service aggregation scenario requirements were to provide: 1)

up to CONUS coverage b) Domestic FSS and DBS services (only)

and c) Transmission at C/Ku/Ka frequency bands.

Variation to Service Aggregation Scenarios: The service

coverage area was to be extended to include up to the entire

western Hemisphere. Additional services including mobile and

data collection were to be considered as well as additional

frequency bands. An intersatellite link capability to

international satellites or other non U.S. satellite or

platforms was to be considered.

2.5.2 Service Aggregation Scenario Selection Criteria

Several interactive concepts are involved in the development

of aggregation criteria. The first and simplest is the

inclusion of multiple. distinct payloads-such as fixed

communications. DBS. or CPS services - on a single satellite. A

second level is aggregation of multiple users within a single

payload. Also, the selection of aggregation criteria must go

hand-in-hand with payload criteria ; the two sets of criteria

cannot be developed independently. As an example, an

aggregation scenario that would result in a payload set whose

mass or power is excessive should be identified early to

preclude wasted effort in the subsequent payload concept and

definition tasks. Regulatory and institutional constraints can

also interact with the ability to aggregate users within a

payload, or even payloads on a platform. An established

satellite user would have to see significant economic benefit

before relinquishing his "very own" system.

The suggested evaluation criteria given in Appendix A to the

RFP for this study included:

a_. Potential communication capacity from an orbital slot.

b_. Impacts on both space and terrestrial plant-in-place.

c_. Communications service reliability/availability.

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Criterion b. has been discussed above vis-a-vis space

impacts. Terrestrial plant-in-place impacts include such

factors as ensuring that an existing carrier's terrestrial

facilities - if its space plant were to shift to the platform -

are still usable or easily modifiable with minimum downtime.

There is an interaction between criteria a and c_. Most users

would be reluctant to place all their traffic on a single

satellite, even if sufficient capacity could be provided in a

single orbital slot for that user. Thus, one could end up

considering different mixes of payloads/users in different

slots. Sparing considerations complicate the problem but must

be taken into account. In spite of the aforementioned problems,

the pressures on orbital slot availability, may very well drive

the FCC to give preference to filings that conserve this

resource or directly regulate the use of the orbital slot.

There are other criteria that could be considered in addition

to those covered above. For example, in evaluating the

inclusion of a payload serving a particular market segment, the

economic benefit of a satellite-based system, relative to other

alternatives, would provide a measure of the likelihood such a

system would be viable. As an example, it would be very

difficult for a satellite-based mobile system to compete with a

cellular terrestrial system in a metropolitan area because of

the latter's high degree of frequency reuse in a small area. On

the other hand, a mobile user should not be expected to provide

two different systems. Hence, compatibility issues must be

considered.

As a result of the Task 1 efforts it was determined that the

following selection criteria be used in the evaluation of the

various service Aggregation Scenarios:

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a. Optimum Communication Capacity From An Orbital Position.

b. Impact On Terrestrial And Space Plant-in-Place.

c. Communications Service Reliability/Availability

Risk Associated With "All Eggs In One Basket".

— Numerical Reliability

Frequency Selection For Availability.

d. Institutional Issues

-- Antitrust Issues

— Regulatory Issues (FCC. CCIR. CCITT)

Insurance Issues

Ownership And Financing

e. Hultipayload Schedule Risk

f. Privacy Issues

g. Restriction On Re-Allocation Of Existing Service

h. Orbit Servicing Outages.

2.5.3 Payload Concept Evaluation Criteria

The key evaluation criteria for payload concepts are as

follows:

a. Frequency spectrum utilization

Bandwidth

— Re-use

— Modulation efficiency

b. Inter-system interference

c. Communications service reliability, availability.

d. Growth potential/flexibility

e. Complexity (Risk)

f. Percent payload capacity utilization.

2.5.4 Other Consideration

•

In addition to the technical and performance constraints to

be impo'sed on the Scenario development are various other

parameters to be considered. The three factors examined in this

study are: a) institutional barriers b) regulatory

considerations and c) insurance issues.

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2.5.4.1 Institutional Barriers

If the technical problems in developing, launching, and

operating a geostationary communications platform can be solved

and if the "economies of scale" materialize, the platform may

make economic sense. However, there still remains the problems

of institutional barriers.

The Communications Common Carriers have been restrained by

antitrust laws. This was viewed as a problem even in assembling

the "Carrier Working Group" for the LeRC 30/20 GHz Program.

However, these carriers have a long history of working together

on cooperative projects. The submarine cables, which have been

in operation for almost 100 years, are usually owned by one

carrier, but others have been able to use part of the

capability. Intelsat was formed in 1963 to own the space

segment of the satellites carrying international traffic. This

international consortium has been remarkably successful in

providing global communications services.

The carriers owning domestic and regional communications

satellites have been able to lease spare capacity to one

another. The Anik A satellites leased transponders to U.S.

carriers before the U.S. domsats were launched. Currently. Anik

C-2 has been tilted so that its antenna footprints fall oh the

U.S. rather than Canada, and high power Ku-band transponders are

being leased to U.S.C.I. for television distribution in the

Eastern U.S. The Comstar satellites were bought by Comsat and

leased to AT&T, who in turn subleased channels to GTE. The

Galaxy satellites are unique in that their owner. Hughes

Communications, Inc., did not decide to be a common carrier, but

leased the transponders to carriers. This has become known as a

"condominium" satellite, since the transponders were all sold to

individual owners.

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The platform could follow any of these commercial models:

a.. The platform could be owned by a single organization, and

spare channels could be leased to other carriers.

b. The platform could be owned by a consortium formed for

that purpose, and the consortium members could have

access to the channels.

c.. The plattorm could be developed by a single organization,

and communications channels could be sold to carriers.

An alternate system could have the platform owned by a

government entity. This could presumably be the system chosen

by a government with a PTT (postal, telephone, and telegraph)

organization.

Purposes and Priorities of the Payloads: The purposes and the

priorities of the payloads on the Geostationary Communications

platform affect the institutional barriers. For example, these

barriers can be quite different if the platform is owned by an

international consortium such as Intelsat which operates on a

world wide basis, or by a U.S. Commercial corporation operating

domestically.

The following potential-categories of payloads are possible.

a. Satellite Communications

-- Commercial, domestic

Commercial, international

Governmental, domestic

Governmental, international

b. Meteorological observation and dissemination1

c. Earth resources observation and dissemination

d. Military reconnaissance

e. Scientific observations

f. Engineering tests of components and system.

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Platform Ownership Options: The communications satellite

platform could have a number of different ownership options,

these are listed below, with examples:

a. A U.S. common carrier (e.g.. AT&T. GTE, ITT. WU. RCA

Americom. SBS. etc.)

b. A consortium, of U.S. carriers.

c. A U.S. designated monopoly corporation (a "carriers"

carrier")

d. A U.S. government agency, e.g.. NASA

e. A regional multinational consortium, e.g.. Eutelsat

f. An international consortium e.g.. Intelsat, Inmarsat.

Platform Ownership Responsibility: The responsibilities of

ownership include obtaining or providing for :

a. Regulatory approvals.

b. Financing

c. Contracting for the spacecraft manufacture, payload

integration, testing, and delivery to the launch site.

d. Launch Services.

e. Insurance

f. Tracking. telemetry, and command for a master Earth

Station, including the orbit positioning and deployment,

attitude control, station keeping, environmental control,

configuration management. and radio-frequency

interference control.

g. Payload management. switching control. terrestrial

network management.

"Condominium" Payload Owners' Responsibilities: While the

platform owner's responsibilities involve monitoring and control

of the spacecraft as a whole, the individual payload owners can

be responsible for:

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a. The configuration of communications circuits, switching

within the payload subsystems, and control of the

individual antenna beam "footprints."

b. The switching of spare components within the payloads,

and possibly, the replacement and repair of failed

components or subsystems.

c. An oversight of the platform management which affects the

operations and priorities of the individual payloads.

Representative Scenarios: Several representative scenarios of

platform development are described, in order to review the

institutional barriers which must be overcome.

Scenario #1: A U.S. domestic platform owned by an individual

common carrier: Suppose that the number of communications

satellites over North America grew so rapidly that the orbit

capacity was filled in all practical frequency bands allocated

for communications satellites. In order to increase the orbital

capacity, one of the U.S. carriers assigned an orbital slot by

the FCC proposed to build a large platform, and serve as the

"landlord." subletting space and utilities (power, environmental

control, attitude control, switching circuits, etc.) to other

("condominium") carriers interested in providing their own

payloads for this platform.

The platform owner would have to obtain the regulatory

approvals. The original application to the FCC would have to be

amended to permit this use of his construction permit.

Presumably, the amended platform would accommodate multiple

frequency transmitters and receivers, multiple "spot" beam

i antennas, and could present problems in harmful radio-frequency

•

interference to other authorized users of the radio spectrum.

These concerns, would have to be addressed. and the

communications subsystem designed to obviate any such harmful

interference. The FCC would have to circulate his amendment to

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all interested parties, review the responses, possibly hold

evidentiary hearings, and then decide whether or not to permit

his Application to be amended.

In the event that any of the interested parties was

unsatisfied with the FCC results, he could resort to the

Judicial Branch of the government to .seek legal redress.

Assuming these barriers were overcome, the FCC would submit

the amended application to the International Telecommunication

Union, to insure that no other Administrations would suffer

harmful interference from the operation of the platform in its

assigned orbital position.

In order to permit multiple carriers to cooperate in

designing and integrating communications payloads onto a

platform. the Dept. of Justice would have to waive the

anti-trust laws which are designed to prevent collusion between

carriers on pricing services. Arguments showing this

cooperation was in the public interest would be required to

pursue such a waiver. If the current laws do not permit such

cooperation. then the appropriate Congressional Committees

could consider changes in the law to make this possible.

The FCC has limited the rate of return on domestic

communications carriers to a fixed percentage of the invested

capital. this limitation could restrict the potential profits

of the platform owner, and make it difficult to raise the

finances. While the recent trends have been for less

regulation, these trends may not continue indefinitely.

The platform owner would have to obtain financing for

development and construction. Because of the long lead times

involved, several years would pass before any income would be

realized from the platform's operation. The expenditures would

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start slowly, and build up steadily as the construction took

place. Progress payments would be required for the launch

vehicle, and the owner could incur costs on the order of a

billion dollars or more at the time of the launch.

Since few corporations can generate this much cash from

operating expenses, outside sources of financing will be

required. The "condominium" owners could be a source of these

funds, if they will pay in advance for space on the platform.

Alternatively, the money could be borrowed or raised from

private or public subscriptions. The public subscriptions come

under the jurisdiction of the Securities and Exchange Commission.

Currently, communications satellites qualify for investment

tax credits. These "iTC's" could enable a corporation to deduct

some of the investment in the platform from operating profits in

other activities. This assumes that the current laws on ITC's

and depreciation allowances on high-technology enterprises will

continue, and will apply to the platform as well as other

communications satellites. The Internal Revenue Service must

approve the use of the ITC's for the platform owners.

Insurance must be obtained for the platform, and the large

expenses involved may strain the capacity of the underwriters.

If the perceived risks in the platform exceed those of

conventional satellites, the higher premiums may handicap the

profit potential of the platform.

The launch services may not present institutional barriers,

since the platform will presumably be launched on the space

Shuttle. However, the size of the platform will require more

extensive integration facilities at Cape Canaveral than are

needed for smaller communications satellites.

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After the platform is successfully launched, checked-out. and

is operational, the multiple carriers on-board can effect a

degree of interconnection which is rare in terrestrial

circuits. Properly designed. the platform can permit

interconnection via an on-board switching system of any uplink

with any downlink. This can permit any earth station

communicating with the platform to reach any other earth

station. irrespective of. the frequency bands. While this

versatility can result in better utilization of all

participating earth stations. the coordination in tariff

charges and state and federal regulation of these tariffs can

present new problems.

Assuming that these barriers can be overcome, the platform

could offer a high degree of utilization of the geostationary

orbit "slot", due to the interconnectability and multiple

frequency re-use in "spot" beam antennas.

Scenario #2: An international consortium becomes the platform

owner, and leases out communications subsystems to members of

the consortium. If Intelsat became the owner, the institutional

barriers are less formidable, because many of them have already

been overcome. If a new international consortium were set up in

competition with Intelsat, then the administrations involved

would have to agree to permit competition with Intelsat's

current monopoly.

In this scenario, suppose that a rival international

consortium were set up to serve the heavy traffic areas of the

Atlantic Basin in competition with Intelsat. The U.S. could use

two approaches in permitting free entry into international

*

satellite communications. One is to license the domestic

applications first, and then deal with the other

administrations; the other is to reverse this sequence.

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Within the next several years, the question of whether or not

to permit competition with Intelsat's current monopoly will be

addressed by the Executive Branch (the Senior Interagency Group

on International Communications Policy), by the FCC (either in

licensing procedures or in a broad rule making inquiry), or by

the Legislative Branch (in oversight hearings by relevant

congressional committees). Congress might find it necessary to

amend the Communications Satellite Act of 1962.

Assuming that competition to Intelsat is permitted, then the

platform can communicate with earth stations in a number of

Administrations. Each participating Administration could permit

earth stations communicating on several frequency bands with a

platform positioned over the Atlantic Ocean. Because of the use

of "spot" beams antennas, the power flux densities ("p.f.d.'s")

could be higher than that available from Intelsat satellites,

and smaller earth station antennas could be used. Because of

the direct communications between international corporations, or

video distribution networks, and;the elimination of terrestrial

links and related expenses, the communications circuits would

presumally be cheaper than those involving the local PTT's and

Intelsat.

The institutional barriers which must be overcome to permit

this scenario include the waiving of restrictions on competition

to Intelsat, the permits to construct earth stations by all

participating administrations, the coordination and assignment

of an orbital slot by the ITU. and the permits to use high power

flux densities within the antenna beam "footprints."

The financial barriers are similar to those described

previously, but in this case the funds might be provided by the

sponsoring administrations, or by private ventures from each

corporation in proportion to .the communications capability

subscriptions. The managing entity could be a new consortium,

or an existing satellite operator might be engaged to perform

this service.

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2.5.4.2 Regulatory Considerations

The following government organizations or corporate entities

many present regulatory barriers in establishing a platform

communications system.

FCC: Grants construction permits (licenses) and assigns orbital

slots for domestic applicants. coordinates these slot

assignments with the ITU, coordinates interference complaints by

users of the radio spectrum, and regulates tariffs.

NTIA: Coordinates telecommunications policy in the Executive

Branch of the government.

State Public Service Commissions: Regulates inter-state tariffs.

Dept. of Justice: Enforces the laws governing communications

common carriers.

Congress: Makes the laws governing the carriers.

Courts (Judicial Branch of the Government): Adjudicates disputes

between interested parties.

Dept. of State: Coordinates international agreements with other

Administrations.

ITU (International Telecommunications Union): An agency of the

United Nations which coordinates freguency assignments, orbital

positions, and harmful interference between competing users of

the radio-freguency spectrum.

UN: Parent organization of the ITU; makes policy related to

international broadcasting.

Foreign Governments: Make treaties concerned with international

communications.

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Foreign Government PTT1s.(Postal. Telephone & Telegraph): State

monopolies controlling the earth stations and communications

interconnections on their territory.

IRS (Internal Revenue Service): Regulates the tax credits and

depreciation schedules affecting communications satellite

systems.

SEC (Securities Exchange Commission): Regulates stock offerings

and private placements (which might be used to finance the

platform).

investment Bankers, and venture capitalists; Financing.

Insurance Companies: Underwrite risks on construction and

delivery, launch and commissioning, plus the orbital operations

or the platform. •

NASA: Spacecraft integration at the launch site; launch

services.

Master Control Earth Station: Tracking, telemetry, and control

of the platform in orbit.

It is expected that key regulatory action would be -required

for the following:

a. Domestic Communications (orbital slots. frequency

assignments, power levels, modulation techniques): FCC

for commercial applications, IRAC for government

applications.

b. Heavily trafficked frequency bands may require a

long-term effort with the FCC to clear a platform orbital

slot, or the use of a slot assigned to a satellite owner

(or owners) with waivers to operate a platform.

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c. Formation of consortia of U.S. common carriers will

require anti-trust laws to be waived by the Dept of

Justice.

d. Geostationary slots for both domestic and international

communications must be assigned by the ITU.

e. Broadcasting across national borders requires approval by

the administrations involved, and may involve the U.N.

2.5.4.3 Insurance Issues

The insurance of communications satellites is a relatively

new business. It began with coverage of the launch phase of the

Intelsat I (Early Bird) in 1965. The first coverage of the

operating phase in orbit was with Western Union's Westar I in

1974. The insurance of property damage and malfunctions is now

considered in four phases:

a. Manufacturing

b. Prelaunch. from the time the satellite leaves the factory

until intentional ignition of the launch vehicle

c. Launch, ending with positioning in the geostationary

orbit and (sometimes) checkout on orbit

d. Operation, with periodic renewals throughout the lifetime

of the satellite

The industry has grown to the point that the total sums

insured in 1983 are approximately $1.5 billion. However, the

maximum capability on a single launch is limited to slightly

over $200 million. Because a geostationary communications

platform's cost will exceed this limit, the industry capacity

must grow to support higher levels.

A second type of insurance involves liability claims. Even

though some spectacular unplanned reentries have occurred, such

as the 80-ton Skylab's crash over Western Australia in July of

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1979, only minor damage has resulted. The total industry

capability of third party liability is now on the order of $1

billion.

The geostationary platform poses some unique risks in

comparison with individual satellites. The most obvious is

"putting all your eggs in one basket." A catastrophic event

such as a microroeteoroid impact could totally destroy a

platform. A more likely event such as the loss of the attitude

control subsystem could also render the platform useless.

However, with the large weight and space and more redundant

subsystems, a means of regaining control can be incorporated

into the platform. The insurers must review the reliability

assessments of the platform and compare them with individual

satellites in order to determine the premiums that should be

charged.

Another risk peculiar to the platform is the potential for

radio-frequency interference (RFI) between diverse payloads.

The juxtaposition of high-power transmitters and sensitive

receivers has caused unanticipated problems on satellites

carrying multiple payloads. For example, the high powered

transmitters on Fleetsatcom produced intermodulation products

(IMP) from nonlinear components which jammed the receivers.

This satellite required extensive redesign and suffered schedule

delays and cost overruns. The insurers must follow the designs

and tests during the platform development to determine if this

risk is acceptable. Alternately, the insurance policies could

be written to preclude claims resulting from RFI between

separate payloads.

The insurance of a large and expensive communications

platform could present problems with the space insurance

community in their present state of affairs. The total exposure

on a single satellite launch has increased from a value of

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©1IGJNAL PAQE US

OF POOR QUALITY

approximately $10 million in the late 60's. to a value slightly

over $100 million currently. This trend is illustrated in

Figure 2.5-1.

120

Maximum & Average Insured Values

Maximum-}

68 70 72 74 76 78 80 82 84

Calendar Vear

Figure 2.5-1. Insurance on Individual Satellites

On multiple satellite launches from a single launch vehicle,

this exposure can be multiplied by a factor of two or three.

The insurance underwriters became painfully aware of these risks

during the llth Shuttle Mission (Feb. '84) in which the failure

of the PAM-D Perigee Kick Motors resulted in losses of $180

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ORIGINAL PAGE SS

OF POOR QUALITY

million for WESTAR VI and PALAPA B2. While these losses may be

lessened by recovery and re-sale of these errant satellites, the

loss was a bitter one for the underwriters. The subsequent loss

of approximately $80 million launch of INTELSAT V F9 on the

previously reliable Atlas/Centaur Launch Vehicle exacerbated the

problem.

Ultimately, the space insurance business must be profitable

in order for it to continue. Figure 2.5-2 shows the losses

exceeding the premiums in '79. and rising sharply with the three

losses mentioned above in184. At the present time the total

cumulative losses are approximately double the cumulative

premiums which have be collected.

500

Cumulative Net Premiums & Losses

•••«••••

1 ! i I i I

72 74 76 78 80

Calendar Vear

Figure 2.5-2. Cummulative Satellite Insurance

82 84

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The insurance premium rates will have to increase to permit

underwriters to become financially healthy again. The launch

and commissioning rates have been between approximately 6% and

10% depending on the perceived reliability of the launch vehicle

used. The rates quoted since the disasters of .'84 have been

roughly doubled. If the launch reliability improves, and the

higher premiums contribute to the financial health of the

underwriters, then their capacity can grow to the point that

they could support a platform launch.

The platform may cost a billion dollars or more. This large

expense will probably require outside financing. and the

financiers will insist on insurance to limit their exposure.

The successful launch and testing of an experimental version of

the platform would help reduce the perceived risk on the first

platform launch.

If the premium costs are much higher than that for individual

communications satellites, the introduction of platforms may be

delayed. Alternatively, the insurance could be written with

deductibles; either the loss of one platform in a series of

platform launches, or other limitation on the underwriters'

payments in case of loss. In the case of a platform launched by

government organization such as NASA, the practice has been to

self-insure. This could be another reason that the initial

platform would be experimental.

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SECTION INDEX

Page

3.0 AGGREGATION SCENARIO DEVELOPMENT (TASK 2) 3-1

3.1 OVERVIEW 3-1

3.1.1 Rationale used in Scenario Development 3-2

3.1.2 Adaptation of Traffic Models 3-7

3.1.3 Terrestrial System Characteristics 3-9

3.1.4 Orbit Allocations 3-9

3.2 DESCRIPTION OF EIGHT CANDIDATE SCENARIOS 3-12

3.3 REQUIREMENTS COMPLIANCE MATRIX AND RANKING 3-22

3.3.1 Criteria for Evaluation 3-22

3.3.2 Launch Concept Compliance 3-23

3.3.3 Evaluation Ranking 3-23

3.4 CONCLUSIONS 3-26
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3.0 AGGREGATION SCENARIO DEVELOPMENT (TASK 2)

3.1 OVERVIEW

The purpose of Task 2 of this study was to develop a minimum

of six communications service aggregation scenarios describing

potential groupings of voice. vide.o and data services which

maximize the communications service capacity of a single

location in geostationary orbit.

Using the criteria developed in Task 1 and approved by NASA,

a total of 8 service aggregation concepts were synthesized and

tested against the criteria. The scenarios described potential

groupings of voice, video, and data services that maximize the

communication service capacity of a single location in

geostationary orbit. Information was obtained on the following

parameters:

o Traffic considerations

Capacity for each service by freguency

Re-use estimates based on beam size

Service area covered by service and frequency

o Platform attributes

Estimates of RF power required

Estimates of dc power required

Estimates of weight by service

Development risk assessment

o Required orbit locations by service

o Ground system attributes

Approximate number of earth stations by service

Approximate sizes of earth stations by service

Geographic location of earth stations

Effect on anticipated plant-in-place

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The ranked scenarios and their descriptions were presented to

NASA and five of the scenarios were selected for further

development in this study (see section 3.4)

3.1.1 Rationale used in Scenario Development

The different services that potentially could be provided by

satellite from the geostationary orbit are fixed (FSS).

broadcast (BSS), maritime, aeronautical, land mobile, radio

navigation, meteorological, military, data collection, voice

broadcast, citizen band repeaters, etc. The satellite providing

these services can operate in any one or a combination of three

modes:

o Global coverage

o Regional, zone coverage

o Domestic coverage

Each of the services (FSS, DBS, etc.) uses preassigned radio

freguency (RF) bands allocated by the concerned regulatory

agencies. The agencies coordinate with the International

Telecommunications Union (ITU) for inter-region allocations.

Although planned geosynchronous satellite services are varied.

• it is evident that fixed satellite services communications

satellites outnumber all others. Frequency allocations for FSS,

by international agreement, consist of:

Frequency (MHz) Available RF

Band Uplink Downlink Bandwidth (MHz)

C 5925-6425 3700-4200 500

KU 14000-14,500 11700-12,200 500

Ka 27500-29,500 17700-19.700 2000

Ka 29500-30.000 19700-20.200 500

Thus far. the C band has been the most widely utilized, to

such extent that at certain locations (especially from 70 to

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143 west longitude) it is thought of as a nearly depleted

commodity. To that effect, during the 1979 World Administrative

Radio Conference (WARC-79) and under much pressure from

developing countries and Western European nations, it was

resolved that "A World Administrative Radio Conference shall be

convened not later than 1984 to guarantee in practice, for all

countries, equitable access to the geostationary satellite orbit

and the frequency bands allocated to space services."

Though the Ku-band and particularly the Ka-band are utilized

less than the C-Band. it is likely they will be equivalently

treated within any international and domestic planning

procedure. However. their global. regional. and domestic

allocation, repartition, and methods of utilization will offer

more flexibility than those at the C-band because they are less

thoroughly established from the network design and operation

viewpoints. For instance, while 1 circular or even smaller

spot beams will be desirable for some services in the U.S. at

the Ku and Ka-bands. the same size spot beam will be unlikely at

C-band. An already existing operational structure at C-band

will prevail beyond the late 1990's whereby the usage of the

band is locked to CONUS or 50 states plus Puerto Rico and Virgin

Islands coverages. By the same token it would be hard to

imagine at C-band the realization of a data transmission network

(low speed/medium speed) with roof-mounted small dishes, whereas

1.5 meter or even smaller diameter dishes at the Ku band could

be ideally suited for such a service.

The Ku-band was looked upon as a solution to the congestion

existing in the C-band arc/spectrum. The Ku-band alleviates the

congestion problem because it provides more available spectrum

and therefore more capability than the C-band alone. However,

also to be considered is that the capacity of the C and Ku-bands

can be colocated or combined on one payload in orbit, thus

optimizing usage of the orbit arc/spectrum. Additionally, the

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two bands can be interconnected to create specialized networks,

not to mention the economies of scale that can be achieved for

transponder costs. This can be extended to include the Ka band,

which is quite attractive for very large capacity voice and data

transmission (multicarrier FDM/FM and TDMA).

It is interesting to notice that whereas up to a few years

ago the capacity provided for CONUS coverage from one orbital

location was twelve 36 MHz C-band transponders, the aggregation

of C/Ku/Ka-bands and the use of dual polarization make it

possible to have as many as 168 (24 C + 24 Ku + 120 Ka)

equivalent 36 MHz transponders from the same orbital location

with no other reuse scenario.

The North American arc. which is facing C-band congestion

problems, will get some relief from an orbital spacing reduction

to 2° from the current 4°. However, the North American arc.

which presently extends from 70° to 143°. (U.S. orbital arcs

extend from 70° to 102° and from 118° to 143° with the Canadian

arc extending from 102° to 118°). is in jeopardy of being

reduced. Mexico has already received locations in the Canadian

o o

arc at 113.5 and 116.5 and Brazil has received locations

at 65° and 70° at the end of the North American arc. In

addition, Columbia has been allocated two orbital locations at

75.0 and 75.4 for it's planned domestic satellite system.

It is anticipated that parts of it will be sought by other

Region 2 countries. This is especially true of spots within the

orbital arc from about 60° to 90°, which will be contested by

the U.S. on one hand and Central American and Caribbean

countries on the other. On the other hand, recent FCC filings

have indicated that the sought-after orbital positions requested

for U.S. coverage extend as far down as 55 west longitude.

Taking into consideration present orbit/spectrum constraints,

available satellite and launch technology capabilities (physical

3-4
Aerospace &

Communications Corporation

dimensions, weight, and power), a growing requirement for the

need for transponders, and the economies of scale derived by a

larger number of transponders on a given spacecraft, leads to a

future generation of increased capability communications

satellites (platforms) that will weigh about 5000 Ib (2265 kg)

in geosynchronous orbit at beginning of life. Such a platform

could be stretched up to a weight of 13.000 to 14.000 Ib. still

making use of single STS launch). More missions could be

accommodated and a payload of about 200 equivalent 36 MHz

C/Ku/Ka-bands communications transponders achieved. If the same

economies of scale are applicable as shown in Table 3.1-1.

reduced cost per transponder per year should be achieved. The

cost per transponder per year has dropped from about $10 million

in 1964 for Early Bird to about $370.000 today and is projected

to drop to about $190.000 by 1987. The data in Table 3.1-1 has

been compiled by Ford Aerospace research.

Table 3.1-1.

History of Cost per Transponder Year

Number of Cost*/

Procurement Transponders Transponder/

Year Satellite Trans ponders /Band Year$M (1982)

*

1972 Westar 12 C-band 0.65

1974 Satcom 24 C-band 0.50

1981 Galaxy 24 C-band 0.37

1981 Satcom 24 C-band 0.26

1982 Spacenet 36 Hybrid 0.28

1987 FASSC 54 Hybrid 0.19

*Launch plus satellite

The same, analysis can be applied to other services and in

particular to BSS. where the initial STC program direct

broadcast satellite was planned as a three channel system, to

where subsequent DBS systems will be considerably larger.

perhaps reaching a capacity of up to 32 high-power RF channels

per orbital slot as allocated by RARC-83.

3-5
Ford Aerospace &

Communications Corporation

With the basic services of voice, video, and data to be

provided as before but where changes are bound to happen due to

growing requirements, larger throughputs, use of new RF bands,

planning and optimization of the orbit/spectrum, and the

increasing cost effectiveness of transponders, a number of

service aggregation scenarios can be postulated. Among these

are:

o FSS only at C/Ku/Ka bands

o DBS only at Ku band

o FSS and DBS at C/Ku/Ka bands

o DBS and FSS (TV distribution only) at C/Ku bands

o FSS and mobile at L/C/Ku/Ka bands

o FSS (data transmission only) at Ku/Ka bands

A short description of each of these possible scenarios

follows:

o FSS using up to 7000 MHz of bandwidth that will fulfill

long distance and regional telephony requirements as well as

data and video transmission requirements throughout the U.S.

and/or between the U.S. and Western Europe on one hand, and

the U.S. and countries of the Americas on the other.

*

o DBS for Region 2 using the 12.2 to 12.7 GHz RF band with

direct and indirect circular polarization. An overall of 256

x 24 MHz RF channels are available for the U.S. from 8

orbital positions (8 x 32 channels) at 61.5°. 101°, 110°.

119°. 147°. 157°. 166°, and 175° of west longitude. 192 RF

channels are available for Canada from 70.5°. 72.5°, 82°.

91°. 129°. and 138° west longitude. Both Brazil and Mexico

have also expressed multichannel requirements from each of 4

orbital positions. Other Region 2 DBS aggregation

possibilities are 115° west longitude for the Andean

countries group, and at 103/04° west longitude for Colombia

and Venezuela.

3-6
Ford Aerospace &

Communications Corporation

o Mixed FSS and DBS missions using C/Ku/Ka bands serving

the U.S.. Western Europe, and Japan. Platforms would be

located at pre-established DBS orbital positions and provide

voice and data service transmissions as well, conforming to

designated and established limits of power flux density.

o Considerable TV programming as well (SMATV) transmission

is presently taking place in the U.S. at the C-band with new

service deployment planned at the Ku-band. These transmission

media will prevail throughout the 1990s. A mix of FSS (TV

transmission and distribution only) with downlinks between

3700-4200 MHz and 11700-12200 MHz and BSS services with

downlinks between 12200-12700 MHz from pre-established DBS

orbital positions could be envisaged.

o Mixed FSS at C/Ku/Ka bands and mobile land services at

VHF and L bands can be envisaged for the U.S. and/or between

the U.S.. the Americas, and Western Europe.

o Data transmission requirements to be handled at Ku and Ka

bands, thus allowing a capacity in excess of 6 Gb/s for a mix

of high, medium, and low transmission bit rate services

throughout the U.S., and between the U.S.. other countries of

the Americas, and Western Europe. This should be particularly,

attractive for low capacity users with roof-mounted small

diameter antennas.

3.1.2 Adaptation of Traffic Models

For each service aggregation scenario, the basic traffic data

bases developed in Task 1 were adapted to fit the particular

scenario.

The adaptation required also depended on the traffic type

being considered:

3-7
Ford Aerospace &

Communications Corporation

a.. Trunking Services -A given earth station may serve

several SMSAs. The NASA-provided traffic models were to the

SMSA level. The SMSA-SMSA traffic was mapped to earth stationearth station traffic. This mapping depended, in turn, on the

earth stations selected

b. GPS Services - In this case the traffic need not be

mapped to earth stations because a large metropolitan area would

have hundreds of such stations in close proximity, and it is not

necessary to have traffic data at this level of detail for

payload design. SMSA-SMSA data (including "artificial" SMSAs)

was adequate in this situation. Space plant in place, such as

SBS. can affect the potential platform traffic.

c. International - This traffic is routed to a very small

number of gateway locations. The Intelsat traffic data base is

by country only and is not broken down to individual earth

stations. As long as the beam pattern covers the appropriate

gateway terminals. then country-country data is adequate.

Intelsat plant in place would need to be considered, although

current Intelsat planning certainly envisions their carrying all

international satellite traffic.

d. Point-to-Multipoint and Multipoint-to-Point - These types

of traffic, such as DBS or data collection, will involve broad

coverage areas. In these cases traffic estimates indicated that

only one to four beams were necessary even if it is scanned.

e_. Other - Adaptations of traffic data were evaluated on a

case-by-case basis.

For those cases in which a data base was adapted to a

scenario, a Ford Aerospace computer program was utilized. One

of the capabilities of this program is to sequentially read in

point-to-point traffic demands and match those demands with an

3-8
Ford Aerospace &

Communications Corporation

earth station file. The program implicitly assumes all traffic

endpoints are in the earth station file. A simple change to the

program would allow traffic to be dropped if one or both

.endpoints are not in the data base.

3.1.3 Terrestrial System Characteristics

The selection of earth station location and size can have a

strong interaction with traffic considerations. The main area

where the geographic distribution of earth stations is important

is in trunking traffic.

This is not to say some modeling of earth station population

in nontrunking applications is inappropriate. For example, in

developing a traffic data base for a mobile system, one approach

would be to estimate the number of terminals by regions, such as

offshore or rural/hinterland areas, and assume calling rates and

holding times to derive erlangs of traffic, which in turn can be

converted to circuits based on a blocking criterion. Traffic

data would be on a region-region basis; terminal population

estimates are only used as an intermediate step in the process.

3.1.4 Orbit Allocations

Initially, domestic service was provided by satellite

carriers between a few general-purpose earth stations located

near major metropolitan areas. The FCC generally has not until

recently required showings of competitive feasibility or

economic viability by new applicants in the interest that the

public could benefit from diverse approaches offered by multiple

entrants. However, the FCC has found it necessary to govern the

assignment of the limited number of available orbital

locations. The objective appears to be to accommodate as many

applications as possible with a minimum of regulatory intrusion

and administrative proceedings. The specific orbital location

3-9
Ford Aerospace &

Communications Corporation

assigned by the FCC to each satellite takes into account not

only the requirement of the payload application, but also the

requirements of other satellites. Such assignments are usually

made on a temporary basis and are subject to change by

Commission order. The FCC retains this flexibility in order to

accommodate the changing requirements of existing carriers as

well as new domestic and foreign applications. Although the FCC

has not imposed specific technical operating standards beyond

those required by the ITU's International Radio Regulations, it

has adopted orbital spacing criteria to conserve orbital arc.

These criteria limit payload concept development and design

latitude. The Commission had until April of 1983 an established

a policy of 4° orbital spacing at 6/4 GHz and 3° at 14/12

GHz. The stated policy now is to move toward 2 spacing in a

phased plan. In July of 1985 in issuing licenses to a series of

new applicants, the FCC also re-allocated the orbital locations

of existing satellites requiring some to be moved 1 - 2 .

It is essential that the means of regulation, innovations,

and strategies be examined so as to optimize usage of orbit and

spectrum. This optimization is accomplished as follows:

a_. Use of Ku and Ka bands to allow more spectrum and

therefore greater capacity than at C-band alone. Use af the

three bands that might complement each other in terms of

services will implement the fixed satellite service. The

related technologies are available; yet one can argue that the

higher band components are more expensive than those at C-band.

at least until such time that the demand for Ku and Ka-band

components has caught up with that at C-band.

b. Achieve greater capacity at each orbital slot by:

1. Utilizing each band twice through dual polarization.

The usage of only half of the band from a slot is a waste

of the capacity available at that slot.

3-10
Ford Aerospace &

Communications Corporation

2. Using hybrid satellites or allowing for colocated

C/Ku/Ka band satellites (coincidental orbital slots).

3. Cross-strapping the C/Ku/Ka bands to allow for network

connectivity, that will make available more growth

capability for network users.

c_. Utilize frequency reuse whenever enough spatial isolation

exists. if the geographical separation between coverage areas

is sufficiently large and the spacecraft antenna gain patterns

have sufficiently fast roll-off characteristics. satellites

using the same frequencies can be colocated in the

geosynchronous orbit.

d_. Closer orbital spacing (2 ) to allow more satellites in

orbit. The concern over the scarcity of orbital slots has

motivated the FCC into reducing the orbital spacing of U.S.

communications satellites to 2 for both C and Ku-bands from

their present 4 at C-band and 3 at the Ku-band in order to

create enough orbital slots to satisfy the requirement of new

entrants. Currently there are only two Ka-band applicants and

an orbital spacing of less than 2 should be achievable.

However, no formal spacing policy at Ka-band has yet been stated

by the FCC.

This quest for minimum satellite orbital spacing in turn has

necessitated an assessment of the maximum acceptable adjacent

satellite interference levels, since as these permissible levels

between two networks serving the same area increase, the orbital

separation between the satellites of these networks can be

reduced. To that effect, the International Radio Consultative

Committee (CCIR) Reports 453-2. 455-2. and Recommendation 353-2

have concluded that greater percentages of the total noise

budget can be allocated to interference from other satellite

systems.

3-11
Ford Aerospace &

Communications Corporation

Key factors determining the relationship between the nominal

angle of separation between adjacent satellites in the same

bands and carrier-to-interference ratio (C/I) are the radiation

pattern of earth station antennas and the resulting antenna

sidelobe discrimination. Use should therefore be made of earth

station antennas with improved sidelobe characteristics.

Similarly, spacecraft antennas with shaped beams should be

used, so that they conform to the coverage area in order to

achive high discrimination outside the coverage area.

Although the earth station antenna sidelobe pattern gain

limit is established by G = 32 - 25 log theta. it should be

recognized that the actual average antenna sidelobe

discrimination is considerably larger, thus implying a lower

interference.

e_. Structuring and regulating the usage of the bands

according to voice, video, data services, their capacities and

the type of networks. For instance, the transmission of very

high data bit rates would take place at the Ka-band whereas low

data bit rates transmission would take place at the Ku-band with

roof-mounted earth stations.

3.2 DESCRIPTION OF EIGHT CANDIDATE SCENARIOS

The results of the aggregation scenario development led to

the following eight candidates:

Scenario I - High capacity C and Ku-band FSS and

Ka-band CPS

Scenario II - Medium capacity CONUS FSS and

medium power DBS

Scenario III - Medium capacity CONUS Mobile

Satellite Service (MSS)

3-12
Scenario IV

Scenario V

Scenario VI-A

Scenario VI-B

High capacity medium and high power

DBS

High capacity CONUS FSS and Mobile

(MSS)

High capacity half CONUS FSS.

Region 2 International. ISL to

central/west CONUS and "European

Platform". and Western Altantic

Maritime

High capacity half-CONUS FSS.

Region 2 International. ISL to

central/east CONUS and "East Asian

Platform". and Eastern Pacific

Maritime

High capacity intra and inter

Region II. plus ISL's for European

and Asian international traffic.

plus Region II DBS

These eight candidate scenarios are defined in Tables 3.2-1

to 3.2-8. The information contained in these tables was the

first estimates of the scenario for ballpark sizing and

characterization. During the subsequent concept development and

definition, many of the scenarios as well as their

characterization were modified to make them more suitable

scenarios either technically or economically.

Scenario VII

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3.3 REQUIREMENTS COMPLIANCE MATRIX AND RANKING

3.3.1 Criteria for Evaluation

A summary of the criteria for evaluation and ranking of

aggregation scenario is given in Table 3.3-1. These criteria

are derived from section 2.5.2 plus additions that evolved

during task 2.

Table 3.3-1

Criteria for Evaluation and Ranking of Aggregation Scenarios

o Optimum communications capacity from an orbital position

o Address high growth markets

o Impact on terrestrial and space plant-in place

o Technical feasibility of service grouping

o Service CONUS FSS first then add international and Region

2 international and domestic,

o Communications service reliability/availability

- Risk "all the eggs in one basket"

- Numerical reliability

- Frequency selection for availability

o Institutional issues

- Antitrust issues

- Regulatory issues (FCC. ITU. etc)

- Insurance issues

- Ownership and financing

o Multipayload schedule risk

o Privacy issues

o National security and pride

o Restriction on re-allocation of existing service

o Orbit servicing outages during GEO servicing

3-22
Ford Aerospace &

Communications Corporation

3.3.2 Launch Concept Compliance

The matrix shown in Table 3.3-2 provides a summary of

scenario compliance with "baseline" or "variation" requirements

and with the ability to be accomodated via launch concept ttl or

launch concept #2.

Table 3.3-2

Scenario Compliance with Requirements and Launch Concept

"^ -_ SCENAR 1 0

CONCEPT CRITERIA -^_

"BASELINE" REQUIREMENT

"VARIATION" REQUIREMENT

LAUNCH CONCEPT 1

LAUNCH CONCEPT 2

I

X

X

II

X

X

I II

X

X

IV

X

X

V

X

X

VI

A

X

X

VI

B

X

X

V I I

X

X

3.3.3 Evaluation Ranking

A ranking of the ability of each of the scenarios to

accomodate the various evaluation criteria is given in Table

3.3-3. A score of 1 represents the highest ranking to be

achieved and a score of 8 is the lowest.

With no weighting functions to be applied among each of the

criteria, and with equal incremental values applied to rankings

within each criteria, the following ranking was obtained:

3-23
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3-25
Ford Aerospace &

Communications Corporation

Highest Scenario IV

Scenario II

Scenario III

Scenario I

Sceanrio V

Sceario VI-B

Scenario VI-A

Lowest Scenario VII

3.4 CONCLUSIONS

Eight scenarios were developed and ranked as an output of

Task 2. A presentation of results was made to NASA-Lewis on 7

February 1985.

NASA selected Scenario II. IV. V and VI-A for development in

Task 3. It was also decided to drop the mobile satellite

service payload from Scenario V because it was a one of a kind

payload that had significant impact on the configuration of the

payloads. As the development of Scenario VI-A proceeded it

became clear that the concept of an east and west half-CONUS

coverage satellite did not make sense because the ISL between

them would have become a high volume (approx. 9-10 Gb/s) link

and this did not seem reasonable. Thus the concept was changed

to full CONUS coverage and the split of the international and

regional and domestic coverages changed. After the Task 3

review. and seeing the VI-A development NASA added the

development of the VI-B Scenario to complete the Region 2

coverage requirements.

During the development of Scenario V. it became evident that

the 15 foot reflectors, selected to be compatable with rigid

reflectors in shuttle, provided a reasonable amount of re-use at

C and Ku-band to be consistant with a 1/3 to 2/3 split in analog

3-26
Ford Aerospace &

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to digital traffic consistent with projections beyond the year

2000. This payload then became the basic CONUS coverage package

for subsequent Scenarios.

A summary of the characteristics of the selected payloads is

provided in Figure 3.4-1.

3-27
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3-28
Ford Aerospace &

Communications Corporation

SECTION INDEX

Page

4.0 PAYLOAD CONCEPT DEVELOPMENT (TASK 3) 4-1

4.1 OVERVIEW 4-1

4.2 APPROACH 4-3

4.2.1 Background 4-3

4.2.1.1 Antenna Coverage 4-3

4.2.1.2 Frequency Plan 4-6

4.2.1.3 Access Method 4-7

4.2.1.4 Modulation Scheme 4-10

4.2.1.5 Application of Coding 4-13

4.2.1.6 Connectivity Arrangements and Processing 4-17

4.2.1.7 Ground Asset Feasibility 4-24

4.2.2 Space/Ground System Trades and Concept Ranking 4-25

4.2.3 Traffic Loading Analyses 4-26

4.2.3.1 Computer Programs 4-26

4.2.3.1.1 Traffic Data Base Program 4-26

4.2.3.1.2 Traffic Loading Program 4-31

4.2.3.2 Traffic and Payload Design Optimization 4-34

4.2.3.2.1 Single Satellite Traffic Loading 4-34

4.2.3.2.2 Traffic/Payload Assignments 4-35

4.2.3.2.3 Effective Reuse 4-37

4.2.3.2.4 Traffic Balancing 4-38

4.2.3.2.5 Connectivity 4-39

4.2.3.2.6 Beam Overflows 4-40

4.2.3.2.7 Modularity of Capacity 4-41

4.3 SCENARIO II PAYLOAD CONCEPT DEVELOPMENT 4-42

4.3.1 General Description • 4-42

4.3.2 Institutional and Regulatory Issues 4-42

4.3.3 Summary Antenna Coverages 4-46

4.3.3.1 Ka-Band Fixed Spot Beams 4-46

4.3.3.2 Ka-Band Scan Beams 4-47
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SECTION INDEX (Cont.)

Page

4.3.3.3 Ku-Band FSS Beams 4-49

4.3.3.4 C-Band Beams 4-50

4.3.3.5 Ku-Band DBS Beams 4-50

4.3.4 Transponder Configurations 4-51

4.3.4.1 Ka-Band Trunking 4-51

4.3.4.2 Ka-Band CPS 4-54

4.3.4.3 Ku-Band FSS 4-57

4.3.4.4 C-Band 4-57

4.3.4.5 Ku-Band DBS 4-57

4.3.4.6 Frequency Plan and Modulation/Access 4-60

4.3.5 Traffic Loading 4-60

4.3.6 Terrestrial System Characteristics 4-64

4.4 SCENARIO IV PAYLOAD CONCEPT DEVELOPMENT 4-65

4.4.1 General Description 4-65

4.4.2 Institutional and Regulatory Issues 4-65

4.4.3 Summary Antenna Coverages 4-69

4.4.3.1 Ku-Band FSS Beams 4-69

4.4.3.2 Ku-Band DBS Beams 4-69

4.4.4 Transponder Configuration 4-69

4.4.5 Traffic-Loading 4-74

4.4.6 Terrestrial System Characteristics 4-74

4.5 SCENARIO V PAYLOAD CONCEPT DEVELOPMENT 4-75

4.5.1 General Description 4-75

4.5.2 Institutional and Regulatory Issues 4-75

4.5.3 Summary Antenna coverages 4-78

4.5.3.1 Ka-Band Fixed Spot Beams 4-78

4.5.3.2 Ka-Band Scan Beams 4-78

4.5.3.3 Ku-Band FSS Beams 4-78

4.5.3.4 C-Band Beams 4-80

4.5.4 Transponder Configuration 4-80

4.5.4.1 Ka-Band Trunking 4-80
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SECTION INDEX (Cont.)

Page

4.5.4.2 Ka-Band Scan 4-80

4.5.4.3 Ku-Band FSS 4-80

4.5.4.4 C-Band 4-81

4.5.4.5 Frequency Plan and Modulation/Access 4-82

4.5.5 Traffic Loading 4-84

4.5.6 Terrestrial System Characteristics 4-86

4.6 SCENARIO VI-A PAYLOAD CONCEPT DEVELOPMENT 4-87

4.6.1 General Description 4-87

4.6.2 Institutional and Regulatory Issues 4-91

4.6.3 Summary Antenna Coverages 4-93

4.6.3.1 Ka-Band Fixed Spot Beams 4-93

4.6.3.2 Ka-Band Scan Beams 4-93

4.6.3.3 Ku-Band FSS Beams 4-94

4.6.3.4 C-Band U.S. Beams 4-94

4.6.3.5 C-Band Regional/International Beams 4-94

4.6.3.6 C/L Band Maritime Beams 4-94

4.6.4 Transponder Configuration 4-95

4.6.4.1 Ka-band Trunking 4-95

4.6.4.2 Ka-band Scan 4-95

4.6.4.3 Ku-band (FSS) Configuration 4-96

4. 6.'4.4 C-band (CONUS) Configuration 4-96

4.6.4.5 C-band (Regional/International) Configuration 4-97

4.6.4.6 C/L-band Maritime Configuration 4-98

4.6.4.7 Intersatellite Links . 4-98

4.6.4.8 Frequency Plan and Modulation/Access 4-99

4.6.5 Traffic Loading 4-99

4.6.6 Terrestrial System Characteristics 4-104

4.7 SCENARIO VI-B PAYLOAD CONCEPT DEVELOPMENT 4-105

4.7.1 General Description 4-105

4.7.2 Institutional and Regulatory Issues 4-105
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SECTION INDEX (Cont.)

Page

4.7.3 Summary Antenna Coverages 4-105

4.7.3.1 Ka-Band Fixed Spot Beams 4-105

4.7.3.2 Ka-Band Scan Beams 4-105

4.7.3.3 Ku-Band U.S. Beams 4-105

4.7.3.4 Ku-Band Non U.S. Beams 4-108

4.7.3.5 C-Band Non U.S. Beams 4-109

4.7.3.6 C/L-Band Maritime Beams 4-109

4.7.4 Transponder Configuration 4-110

4.7.4.1 Ka-Band Trunking 4-110

4.7.4.2 Ka-Band Scan 4-110

4.7.4.3 Ku-Band U.S. 4-111

4.7.4.4 Canadian Domestic. Regional & International 4-111

4.7.4.5 Mexico/Caribbean Configuration 4-112

4.7.4.6 South America Configuration 4-112

4.7.4.7 C/L-Band Maritime Configuration 4-112

4.7.4.8 Inter-Satellite Links 4-112

4.7.4.9 Frequency Plan and Modulation/Access 4-116

4.7.5 Traffic Loading 4-116

4.7.6 Terrestrial System Characteristics 4-117

4.8 CONCLUSIONS AND RANKING OF SCENARIOS 4-118

4.8.1 Conclusions 4-118

4.8.2 Bandwidth and Reuse 4-118

4.8.3 Modulation Efficiency 4-119

4.8.4 Throughput 4-119

4.8.5 Utilization 4-122

4.8.6 Digital/Analog Tradeoffs 4-124

4.8.7 Qualitative Issues 4-126

4.8.7.1 Interference 4-126

4.8.7.2 Reliability/Availability 4-127

4.8.7.3 Growth Potential/Flexibility 4-128

4.8.7.4 Complexity 4-130

4.8.8 Ranking 4-131
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4.0 PAYLOAD CONCEPT DEVELOPMENT (TASK 3)

4.1 OVERVIEW

The purpose of the payload concept development under Task 3

of the study was to define the selected Communication Service

Aggregation Scenarios that were determined as an output of Task

2. The initial four concepts were Scenarios II. IV, V. and

VI-A. Subsequent to the Task 3 Review. Scenario VI-B was added.

The key inputs to this effort from Task 1 results include:

a. System constraints and regulatory issues.

b. Space/ground plant-in-place data base.

c. Communication technology forecast data base.

d. Payload service technology forecast data base.

e. Payload concept criteria.

These inputs were synthesized under Task 2 into the NASA

approved aggregation scenarios.

The process of developing payload concepts and their

communications architectures involves essentially the following

factors:

a. Quantify aggregation scenarios in terms of data

bandwidth requirements.

b. Devise payload concepts to satisfy above requirements,

subject to payload concept criteria already developed.

c. Optimize payload concept through system-wide trades of

payload configurations and forecast technology advances

of major component hardware/software/firmware.

The design process was iterated so that payload concepts and

their attendant communications architectures were judged

feasible. Table 4.1-1 describes some of the techniques employed

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in designing the payload concepts. Actual traffic loading to

the payloads was performed. If payload designs do not consider

traffic distributions, then poor utilization (fill factors) may

result in the actual system.

Table 4.1-1

Payload Design Objectives

Minimize Cost per Revenue-Producing Circuit*

By Appplication Of:

o FREQUENCY REUSE

o TRAFFIC BALANCING

o MAXIMIZATION OF STATIC-SWITCHED FILL FACTORS

-- CONNECTIVITY

— BEAM OVERFLOW

o ON-BOARD PROCESSING

o EQUIPMENT QUANTITIES TAILORED TO TRAFFIC

* A revenue-producing circuit is the

actual traffic carried.

Communication payload concepts are described in terms of:

o Antenna Coverage

o Freguency Plan

o Modulation and Coding Scheme

o Access Methods

o Connectivity and Processing

The corresponding terrestrial system characteristics are

presented as station system parameters and hardware, software,

and operational considerations. Finally, the advantages of each

payload concept are presented along with an evaluation and

ranking.

4-2
Ford1

, Aerospace1 &'

y ?vCp,mrpunicatiohs 'Oprporation

4.2 APPROACH

4.2.1 Background

Since the advent of the early communications satellites, both

space segment and ground segment have evolved to higher levels

of performance, reliability, and lower cost. Some of the most

important aspects of economic/technological developments. in

their impact on payload concept, concern spectrum utilization,

system related technologies. TDRSS. spacecraft/earth station

technology and STS and launch technology.

Information regarding the various parameters used to describe

a payload concept (listed in Section 4.1) is provided in the

following subsections.

4.2.1.1 Antenna Coverage

Antenna coverage plays an important role in payload concept

development. Early satellites provided global coverage using a

single polarization. However, as traffic grew, some form of

frequency reuse became necessary. Frequency reuse can be

achieved by using multiple-beam antennas and/or dual polarization. Key considerations in concept development here are

some major tradeoffs in terms of EIRP. adjacent beam interference, polarization isolation, and antenna complexity. For

example, of the three major types of multiple beam antennas in

terms of today's technology, reflector types are most commonly

used (Intelsat IV. IV-A. Anik. Westar and RCA/Satcom) because

they are relatively simple, lightweight, and easy to produce at

low cost. The large feed structures of the reflector type,

however. often impose a blockage constraint in the system

design. An array-type antenna (DSCS II and Intelsat V). which

consists of electrically steered, uniformly spaced radiators,

combines output at each array element to form multiple beams

through a separate beam-forming and steering network. Lens

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ORIGINAL PAQg Is

Of POOR QUALffY

antennas can also be used to create multiple beams by focusing

the energy from a primary array of feed horns through a

microwave lens.

Figures 4.2-1 through 4.2-3 show the possible coverage from

three western hemisphere synchronous satellite positions —

60°W. 90°W and 120°W longitude. respectively. Clearly,

the satellite position and coverage will be determined by the

needs of the customers serviced. The large areas of South

America are spatially remote from CONUS and can efficiently be

serviced from the same orbital slot with compatible systems. It

Figure 4.2-1 Satellite Coverage from 60 W

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Figure 4.2-2 Satellite Coverage from 90 W

is possible that services would be a mixture of 1990's

state-of-the-art technology for CONUS coverage and less

sophisticated systems for Central and South America.

Inter-satellite links can be used to link satellites in

different orbital slots and to extend the range of east-west

communications. Such links would most likely be at EHF

frequencies (60 GHz) or light-wave as they would not pass

through and be attenuated by the atmosphere.

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Figure 4.2-3 Satellite Coverage from 120 W

4.2.1.2 Frequency Plan

The frequencies presently allocated to. non-military satellite

communications in North America are the C band and the K band.

The C band is the 6/4 GHz; the K band is further divided in.to the

Ku band (14/12 GHz) and the Ka band (30/20 GHz).

The C band shares spectrum with terrestrial microwave

systems. Advantages of the C band are that the signals are

relatively free from atmospheric effects, the electronics are

presently less costly, and the technology is further developed.

The disadvantage, in addition to band congestion is that the

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power density is limited by- FCC regulations to avoid interference with terrestrial microwave systems. This usually

necessitates larger, more expensive antennas. The advantages of

the K-band are that the satellites can be spaced more closely in

orbit and the downlink power density can be higher, as there is

no concern for interference with terrestrial microwave systems

at present. This implies a smaller and less costly earth

station antenna. The disadvantages include the fact that the

signal is subject to atmospheric interference, and rain loss in

excess of 10 dB is a major design concern.

Selection of an appropriate freguency plan depends on many

factors, such as antenna coverage, traffic, orbital allocation,

and interference issues. For example, the Ka-band fixed spot

beams developed in this study varied from one 500 MHz channel up

to five, depending on the traffic level in each beam. By

adapting the frequency plan to projected traffic levels,

considerable savings in cost. mass, and power were achieved.

4.2.1.3 Access Method

Another vital component in the' payload concept development is

the access method. Various multiple access technigues have been

developed to allow simultaneous use of a given transponder by"

many earth stations. The sharing of payload capacity by many

geographically dispersed users can be achieved by freguency

division multiple access (FDMA). time (TDMA). space (SDMA). code

(CDMA), and a number of hybrid combinations and variations, as

highlighted in Figure 4.2-4.

Because of its proven technology, simplicity, low cost, and

easy implementation to various networks. FDMA was the primary

mode of multiple access in systems until the early 1970's. In

FDMA. the bandwidth is divided into a number of non-overlapping

freguency bands. Assigned bands are separated by guard bands to

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Ford Aerospace &

Communications Corporation

OEHANO

ASSIGNMENT

CONCEPT

NETWORK CONCEPT

Figure 4.2-4 Various Techniques Achieve Multiple Access

reduce interference, and the payload transponder's power is

divided among the accessing carriers. A common transmission

method of FDMA is the multichannel-per-carrier FDM/FM/FDMA.

which usually requires transponder power backoff or special

bandwidth spacing considerations, both to alleviate AM/AM and

AM/PM caused impairments. As such. FDMA has the general

disadvantages of being less capacity efficient, compared with a

single-access mode of operation. A later technique. SCPC/FDMA.

using a single-channel-per-carrier concept, can provide some

efficiency improvement in this regard, especially when it is

used with demand assigned and signal activated schemes to take

advantage of the usually low duty cycle and statistical

randomness of user traffic (e.g.. SPADE/Intelsat) . SCPC/FDMA is

particularly useful for small users in regional or domestic

systems, but is not feasible for heavily aggregated high trunk

traffic.

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Ford Aerospace &

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Since its initial development in the 1960's. significant

advances have been made in TDMA. In TDMA. a given transmission

time frame is divided into a number of generally non-overlapping

time slots. Assigned channel slots are separated by guard time

to reduce adjacent channel inter-symbol interferences, and the

payload transponder's power is devoted to a single channel on a

duty cycle basis. TDMA. in theory, yields the highest channel

capacity because the only inefficiency arises from the guard

times between adjacent channel slots, these times can be very

small with improvements in synchronization/timing and network

control techniques.

Some of the well known advantages of TDMA are:

o It is possible to make full use of transponder power.

Experiments have shown that digital speech interpolation augmented TDMA can provide 6 dB improvement in

transmission capacity.

o Simplifies frequency planning and ground station RF/IF

hardware (e.g., number of up/down converters required)

at the expense of digital hardware/firmware, which is

increasingly less expensive.

o Can directly carry digital formats, and can be used for

voice, data and video transmissions.

o Provides greater compatibility with terrestrial digital

voice and data networks.

o Offers greater flexibility in accommodating future

system growth.

A major disadvantage is that TDMA is not as efficient with

thin route users. This disadvantage may disappear in the long

term if acquisition cost of required EIRP and G/T can be

significantly reduced from a total system point of view.

4-9
Ford Aerospace &

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Another form of TDMA -popular with transactions! and computer

data communications is the packet-switched transmission (e.g..

Aloha and many variations thereof). Packet switching does not

necessarily improve bandwidth efficiency over the traditional

TDMA. However. it provides many simplifications of network

access and network control that have traditionally been a major

cost component of a TDMA system.

i

Space division multiple access (SDMA) is actually another form

of TDMA. where the access is controlled by the payload antenna

visibility. Rapid beam forming and steering synthesis, in conjunction with the multiple beam antenna (MBA), is a requisite

technology.

The code division multiple access (CDMA) uses either pseudorandom noise-like code (PN) or a pseudorandom frequency hopping

(FH) pattern to represent a single bit. or a group of information code bit(s). Combinations of PN and FH are also used.

As a means of multiple access. CDMA has not been extensively

used. If the RF bandwidth is available. CDMA appears to be an

excellent means of achieving low power density transmissions

(e.g.. TDRSS). With recent and projected advances (technology

and cost) in fast frequency synthesizers, surface acoustic

devices and correlation receiver hardware. CDMA may be viable

for multichannel direct broadcast applications.

4.2.1.4 Modulation Scheme

The assignment of modulation scheme(s) and access method(s) is

an integral process of the payload concept development.

Although the performance measures applied to analog modulation

systems (e.g., SNR) do not coincide precisely with those applied

to digital modulation systems (e.g.. BER). they both are a

function of the bandwidth expansion factor m. which is defined

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Ford Aerospace &

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as the ratio of RF spectrum required to the total intelligence

bandwidth that is transmitted by the information source. The

upper performance bounds for both analog and digital modulation

have long been established by applying the bandwidth expansion

factor m to the classic Shannon's equation. Figure 4.2-5

illustrates these theoretical performance bounds. Keeping a

proper perspective of these theoretical bounds is quite helpful

in dealing with projected technologies 15 years from the current

state-of-the-art. Nevertheless. modern digital modulation

techniques can be used as the starting point for modulation

concept development. These techniques include PSK. FSK. ASK.

MSK. APR. and many variations thereof. Figure 4.2-6 illustrates

several basic modulation techniques.

Many factors should be considered in determining the

modulation schemes. It is important to note that the

determination is based. not just on the modem's projected

performance and cost in the 1998 era. but also on the overall

hardware/software environment projected in the same timeframe

from a total payload system point of view.

Among the major factors one should consider in determining the

modulation scheme are:

o Data rate to be applied.

o Data detection performance (Eb/No required for

threshold HER and WER).

o Bandwidth efficiency (BT product required) if the

payload concept is more bandwidth limited from a total

space/ground system point of view,

o Feasibility of error correction/detection coding at

required data rate if the payload concept is more power

limited.

o Ease of modem implementation,

o Impact to overall system concept.

4-11
m

Ford Aerospace &

Communications Corporation

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4-12
Ford Aerospace &

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4.2.1.5 Application of Coding

The merits/demerits of incorporating coding as a system

parameter is a factor in the payload concept development. It

also matters if decoding is performed on board the payload. or

at earth stations, or both.

Forward error control, generally known as FEC. together with

feedback error control, generally denoted as ARQ. are the two

broad categories of error control mechanism employing channel

encoding for communication systems.

In FEC. the receiver design, along with the signal design,

channel encoding, power, and noise, determines the error rate.

In ARQ, where a feedback channel is used, the final performance

measure is usually the effective throughput rate and the

undetected bit .error rate. For extremely low error rate

applications, a hy.brid approach of FEC and ARQ may be used.

Both the FEC and the ARQ approaches are based on a variety of

channel encoding techniques collectively known as coding. For

FEC applications, the emphasis usually resides on the error

correction capability of the coding. For ARQ applications, the

error detection capability of the coding is emphasized.

Figure 4.2-7 illustrates the hierarchy of such error control

mechanisms showing the three basic approaches (FEC. ARQ and

Hybrid) using coding techniques as building blocks. Relative

merits and demerits of these three approaches are highlighted in

Table 4.2-1.

The coding techniques themselves embody essentially three

different code groups: block code, convolutional code, and

synchronization code, which is used mainly for code sync.

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Ford Aerospace &

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1

ARQ FEC HYBRID

ADVANTAGES

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FEASIBLE

• BUFFER OVERFLOU

MAY OCCUR

• MAX COOING GAIN

3.3 dB

• LESS COMPLEXITY

• LESS COOING

GAIN (2 dB)

KTC031

Figure 4.2-7 FEC Tradeoffs

4-14
Ford Aerospace &

Communications Corporation

Table 4.2-1

Error Control Techniques

Technique

FEC

ARQ

Hybrid

Advantage

Constant decoding delay

Constant information

throughput

Needs no feedback

channel

Achieve low UBER

Adapt to channel

quality

Low decoding/complexity

Achieve extremely low

UBER (eg. 10-15

or l.OE-15) . .

Moderate FEC

cost/complexity

Disadvantage

Decoder cost/complexity

Moderate data rate

Needs feedback channel

and protocol

Variable decoding delay.

Round trip delay

burden. Fails when

system margin not

maintained

Needs feedback channel

The basic idea of coding is to introduce structured redundancy

into the information sequence in such a way that the capacity

exists for combating errors introduced into a communication

channel.

After Shannon's theory in 1948, a systematic approach to block

coding based on a formal mathematical algebraic structure

between the parity symbols and the information symbols was

developed. This approach exploits the algebraic structure of

the code for decoding such that an increase in the code length

does not require a corresponding exponential increase in the

complexity (A rough equivalent to the development of the Fast

Fourier Transform (FFT) for the discrete Fourier transform).

Many useful codes were developed as a result. These include the

Golay. Hamming, Reed-Muller. Fire, BCH. Reed-Soloman and

4-15
Ford Aerospace &

Communications Corporation

concatenated codes. Of these, the BCH code appears to be the

best code for AWGN (Additive White Gaussian Noise) channels.

In addition to the systematic algebraic approach of the block

code, a second approach has been developed based on the less

structured probabilistic consideration of channel noise effect.

This approach results in the concepts of recurrent- or

convolutional code and its attendant decoding schemes. The

convolutional codes are considered the most effective coding

developed for an AWGN channel.

For error detection. block code is preferred over the

convolutional code because blocking or segmentation is necessary

to facilitate retransmission of erred data detected. A decoder

for error detection can be easily implemented with any parity

check block code.

For ertor correction, convolutional codes appear to outperform

block codes for the same implementation complexity.

Furthermore. convolutional codes have the following

characteristics:

o Code sync is much simpler. The block code needs to

resolve n-fold ambiguity while a rate 1/2 convolutional

code needs only to resolve 2-fold ambiguity (4-fold for

a rate 3/4 code).

o Channel guality information can bo easily used in

Viterbi or sequential decoding algorithms. That is.

bit quantization (soft decision) of demodulator output

can be applied to the decoder instead of the

demodulator decision itself (3-bit oc 8 level soft

decision gives approximately 2 dB more gain in Eb/No).

o With soft decision, decode can monitor channel quality

in real time.

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Ford Aerospace &

Communications Corporation

Where coding gain is deemed feasible as a system parameter, a

3 dB coding gain can be used to offset any one of the following:

o Cut transmitter power by half

o Reduce antenna diameter by 30% at transmitter or at

receiver

o Increase receiver noise figure by 3 dB

o Increase the data rate by 100%. bandwidth permitting

o Increase the communication link or orbital distance by

40%

o Tolerate 3 dB more of implementation losses

o Increase communication availability by an appropriate

amount depending on rain statistics of sites

Of course. the main purpose of coding gain remains the

reduction of the equivalent bit detection threshold for a given

BER.

Like any other communications resource, coding gain is not

without its limit. Coding gain is upper bounded by the Shannon

capacity theorem. For a PSK channel (with respect to an

Eb/No = 9.6 dB at BER = 1(

9.4 dB for a rate 1/2 code.

Eb/No = 9.6 dB at BER = 10 ). this theoretical bound is about

Since the state of the art achieves a coding gain of about 5

dB at this time, future improvement of 4 dB or so can be

expected. It should also be noted that for algebraic block

codes the existence of any code is further bounded by the so

called Elias bound. Figure 4.2-8 summarizes various current

coding performances as compared to the Shannon bound.

4.2.1.6 Connectivity Arrangements and Processing.

The use of onboard processing covers a wid« range of

functions that can enhance the performance of the total

communications system. There are three major areas of interest:

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Ford Aerospace &

Communications Corporation

10 -]

9.6

9-

8-

7-

_ 6

o

o

Q

ui

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OUJ

5-

4H

1-

IOEAL PSK (UNCODED BER = 10"5)

MAJORITY LOGIC CONVOLUTIONAL CODES

R-S BLOCK CODE (LESS COMPLEX CODES)

R-S BLOCK CODE (MORE COMPLEX CODES)

BCH CODE (LESS COMPLEX CODES)

BCH CODE (MORE COMPLEX CODES)

VITERBI DECODER (LV7000)

2 3

BANDWIDTH EXPANSION

Figure 4.2-8. Performance Envelopes of Decoders

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Ford Aerospace &

Communications Corporation

o Switching/routing

o Signal Processing

o Control

4.2.1.6.1 Switching/Rout ing.

There are several options in providing connectivity for a

given payload. The appropriate choice depends on several

factors, such as traffic distribution, the number of beams, and

the functions the traffic type must support. Figure 4.2-9

summarizes these options by means of simplified block diagrams.

1. No Switching - This configuration is typical of a standard

domestic satellite with CONUS coverage. Generally, the

ouput freguency of the receiver corresponds to the downlink

RF freguency.

2. RF Switching - If freguency reuse and multiple beams are

implemented, static switching may be employed at the RF

(usually the downlink frequency) level. Switching is

normally only done within the same freguency channel (e.g.,

40 or 80 MHz).

3. Interband Switching - An example of this type of switching

is C/Ku band interconnection used on the Intelsat V and is

similar to 2 above except upconverters are reguired on the

Ku downlink.

4. SS-TDMA - The static switch of 2 is replaced by a microwave

switch matrix (MSM) which is dynamically reconfigurable in

real time; uplink access must be TDMA.

5. IF Switching - The constraint in 2 and 3 that switching can

only be done within a freguency channel can lead to reduced

fill factors. The use of IF switching allows greater

flexibility, but at the cost of up and down converters.

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Ford Aerospace &

Communications Corporation

ae

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(Sheet 1 of 2)

4-20
Ford Aerosoace &

Communications Corporation

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(Sheet 2 of 2)

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Ford Aerospace &

Communications Corporation

6. Baseband Processing - The uplink signal is demodulated and

demultiplexed to an appropriate level, and switching can

then be performed. Other signal processing. such as

decoding of digital bit streams, may also be done as

required. Demultiplexing can be to the circuit, Tl, or

higher levels. After switching, the reverse functions are

performed prior to downlinking.

7. Packet Switching - A variant of 6 would be to provide a

packet switch on board the spacecraft. Although satellite

packet systems, such as Aloha, exist today, the satellite

does not perform any routing. Use of a true packet switch

in the spacecraft would provide many advantages over the

Aloha system and would be required in a multibeam case.

4.2.1.6.2 Signal Processing

Signal processing includes several potential functions.

Figure 4.2-10 provides a generic view of signal processing. The

exact functions used depends on the modulation/access schemes on

the uplink and downlink. For example, suppose an architecture

called for FDMA with digital modulation (QPSK or other) within

each access on the uplink and TDM on the downlink. This

approach could reduce earth station complexity and costs, since

burst arrival synchronization is not needed. The various

accesses would be frequency division demultiplexed, demodulated,

and if required for switching, further demultiplxed on a time

division basis. Then the functions of time division

multiplexing and digital modulation would be required to obtain

the output of the baseband processor. The selection of an

appropriate sequence for a given payload will depend on such

factors as earth station capabilities and traffic requirements

4-22
Ford Aerospace &

Communications Corporation

INPUT

^

FREQUENCY

DIVISION

DEMULTIPLEX

•

TIME

DIVISION

MULTIPLEX

«

ENCODE

-»H

^-

DEMOOULATION

SWITCHING/

ROUTING

MODULATION

-»• DECODE

«

TIME

DIVISION

DEMULTIPLEX

«

FREQUENCY

DIVISION

MULTIPLEX

-

OUTPUT

* OPTIONAL

Figure 4.2-10 A Generic Baseband Processor

4.1.6.3 Control

A communications control capability must be provided,

particularly for the switching/routing function. Reconfiguration of the system can take place on either a preplanned or a

real-time basis. An example of the former would be changing RF

connectivity between beams with static switches. This type of

switching would only be done occasionally if significant changes

in traffic patterns were to occur.

A CPS system, however, requires real-time switching at the

circuit level. In the ACTS system, a central or master

controlstation on the ground is required for network control.

With 1998 technology, it may be possible to provide a large

portion of the communications control capability in the

satellite, as is being done in Milstar. This approach would

reduce orderwire traffic and speed the setup of calls.

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Ford Aerospace &

Communications Corporation

Other control functions would include SS-TDMA switch

operation, beam pointing control, crosslink acquisition, and

link control (adaptive techniques for rain fading).

Two important considerations in a control architecture are

reliability and hardening. Single event upsets ("bit flips")are

tolerable in signal processing or switching circuitry, but not

in the control area. Various approaches - including use of a

hardened technology such as CMOS/SOS, redundant (voting)

systems, or error correction, can be used to solve this problem.

4.2.1.7 Ground Asset Feasibility

In order to establish a complete communication system

architecture and to ensure system realizability and compatibility, the supporting terrestrial communications assets are

hypothesized for each service aggregation scenario. The

terrestrial segment under consideration includes the platform

communications control facilities, the projected user terminals,

and their ancillary interfaces to existing terrestrial communications networks.

From a platform communications control viewpoint, the extent

of communication service control -to be performed by a

terrestrial control center. including demand assignment,

resource allocation, and message routing/sorting, can be

evaluated. Such scenarios presuppose continued advances in VLSI

circuitry to permit colocation of digital baseband processing

and switching equipment on a geosynchronnous platform. This

equipment, used in conjunction with the multiple spatial reuse

of spectrum offered by large spot beam antennas. has the

potential of reducing the complexity of existing terrestrial

master control stations while greatly increasing the degree of

throughput.

4-24
Ford Aerospace &

Communications Corporation

4,2.2 Space/Ground System Trades and Concept Ranking

The payload concept development is not complete without an

assessment of the system reliability/availability from a total

space/ground system point of view.

The space/ground system reliability/availability refers to

satellite (including satellite bus) availability and link

availability. The satellite availability is the probability

that a particular satellite will be available for use at a given

time. This availability is a combination of satellite

reliability. satellite replenishment. and in-orbit service

strategy forecasted for 1998. Some of the significant variables

whose values must be estimated in predicting the availability

include:

o Number of satellites to be deployed

o Mean time to failure

o Cost of satellite and cost of delivery

o Cost of in-orbit services and cost of positioning spares

o Turnaround times to replace failed satellite and to

service

o Event threshold that will trigger a decision to replenish

or service

o Probability of further deterioration of payload during

replenishment or service

The link availability is the probability that a link of

specified capacity and quality connecting system users is

operating at any time. Significant variables concerning link

availability are:

4-25
Ford Aerospace &

Communications Corporation

o Satellite availability

o Earth terminal availability

o Satellite visibility

o Signal level variations

o Satellite conjunction

Each of these factors affects the link availability.

4.2.3 Traffic Loading Analyses

The payload concepts developed in Task 3 utilized several

computer programs to manipulate various traffic data bases and

to load the traffic to a given payload. Also, several concepts

have been used to optimize payload designs relative to the

assumed traffic forecasts.

4.2.3.1 Computer Programs

4.2.3.1.1 Traffic Data Base Programs

Two programs were developed to process the 316 x 316 SMSA

traffic distribution tape provided by NASA at the beginning of

the study. These are the "Preprocessor" and "Scale and Convert"

programs depicted in Figure 4.2-11.

It was deemed that working with the full 316 x 316 matrix

would result in a very large amount of time in just bookkeeping

such factors as SMSA-to-beam relationships as design iterations

proceeded. The Preprocessor provides the capability to shrink

the original matrix to a smaller one by mapping each of the

SMSA's to one of N regions, or "pseudo-terminals". No attempt

was made to model all of the terminals on the system. The two

basic mappings employed were to 20 x 20 and 84 x 84 matrices.

The former was used for the 20 Ka-band fixed spot beams, and the

latter was used for all other designs. The 84 regions, which

4-26.
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are sufficient for determining beam coverages, were based on

[Ref. 12]. Figure 4.2-12 illustrates the regions (there are

more than 84 regions, but some contained no SMSA's and hence no

traffic). Appendix A contains listings for the two mappings, as

well as printouts of the 20 x 20 and 84 x 84 matrices.

The original tape gave the distribution only, with the total

7

of all entries equal an arbitrary value of 10 . The output of

the Preprocessor is similarly normalized. The Scale and Convert

program accepts a single number which represents the total

traffic of a given type—voice, data, etc., and converts an NxN

distribution matrix to one whose total entries sum to the given

number (with some roundoff), and with the same distribution.

The total traffic numbers are described in Section 2.2.2.2. The

output is also in binary form for more efficient storage and I/O

in subsequent programs; the original tape was in "print" format.

Input of other traffic data bases, such as Intelsat. Canada,

and Brazil, were manual, and existing programs were used to

convert this input to the common binary format.

Two other programs shown in Figure 4.2-11 had been previously

developed. The "Grouping" program allows one to group terminals

arbitrarily, and provides a group-to-group traffic matrix. This

aids the process of designing beam coverages from a traffic

balancing aspect (see Section 4.2.3.2.4). Other uses, such as

estimating ISL capacity requirements, can be performed with this

program. Examples of the output are given in Appendix B. The

"Pretty Print" program provides a listing of any desired traffic

matrix; examples are given in various appendices (e.g.. Appendix

A).

One additional program, not shown in Figure 4.2-11. was

developed to eliminate all traffic in the original NASA tape

between SMSA's closer than 400 miles. Distances were based on

4-28
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4-30
Ford Aerospace &

Communications Corporation

V&H coordinates of each SMSA provided with the original NASA

tape.

4.2.3.1.2 Traffic Loading Programs

Ford Aerospace developed a set of traffic loading programs

several years ago to analyze payload designs for Intelsat and

other spacecraft. It has been our experience in designing

complex payloads that analysis of the numerous tradeoffs

involved can be significantly enhanced by the use of automated

tools; otherwise, only a very limited set of options can be

investigated. Frequently. preferred designs only become

apparent after many iterations of the design process.

Figure 4.2-13 illustrates the system called SNIPS

Satellite/ Network Integration Planning System; some data inputs

are carried over from Figure 4.2-11. SNIPS is designed

primarily to evaluate a complex payload consisting of manytransponders, multiple beams with frequency reuse, and a large

traffic data base with many earth stations. It is precisely

this type of payload that would be time-consuming to analyze

manually. On the other hand, evaluation of a "simple" payload.

such as DBS. is best performed manually.

Traffic data bases are described in the previous section. The

earth station data base is a file of earth stations that will be

operating with the payload being evaluated. The capabilities of

each earth station are also contained in the data base.

Briefly. the information required is the frequency bands

(antennas), capacity, access type, modulation type, and any

other capability, such as 24 kb/s voice encoding, which affects

usage of satellite capacity. A spacecraft payload data base is

required. Table 4.2-2 lists the elements contained in this

file. Some other inputs, not shown in Figure 4.2-13. are also

used. For example, the total traffic in the data base can be

split between multiple orbital slots on a table-driven basis.

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Ford Aerospace &

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Table 4.2-2

Spacecraft Payload Data Base

Data Base Elements:

o Transponders

- Frequency band and channel

- Bandwidth

- Beam

- EIRP and G/T

- Signal processing

o Interconnection and Switching

- Permissible interconnections

- SS/TDMA

- Circuit

o Beams

- Frequency band

- Earth stations covered

- Scanning spot beams

The heart of the system consists of two computer programs. The

first program translates point-to-point traffic to a set of

beam-to-beam traffic matrices by type: modulation. frequency

band. etc. These matrices are built up by matching each

point-to-point demand with the earth station capabilities and

their beam location, as defined in the spacecraft data base,

multipling by the slot diversity factor for the particular

orbital slot under study, and accumulating the result in the

appropriate beam-to-beam entry. This program is a simple,

sequential process which automates a very large and tedious

task. It is interactive, and multiple sets of beam-to-beara

matrices can be generated and stored at one time.

4-32
Ford Aerospace &

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The second program, also interactive, utilizes a combination

of user input from the terminal and an optimization routine.

The information the user must supply is how each transponder is

operated (e.g.. FDMA. TDMA) and the interconnection or switching

of transponders, including SS-TDMA. A maximal flow algorithm is

used to find the optimum loading using the set of beam-to-beam

matrices discussed above. Outputs at the terminal are available

which guide the user in determining a better transponder usage

and interconnect plan. These outputs include such items as

transponders with low fill. or unsatisfied demands. This

iterative process continues until no better plan can be found.

The final output gives the complete loading and can be used to

evaluate the efficacy of a particular payload complement. Based

on this evaluation, the earth station or spacecraft data bases

can be altered and the process repeated.

A second version of the transponder loading^program had to be

developed for this study to analyze some of the very large

payloads considered. Storage limitations on the PDP-11/70

prevented using the existing version of the program for these

payloads. The new version did not utilize the maximal flow

algorithm because the flow network set up by the program is the

major driver regarding storage. The capabilities of the maximal

flow algorithm are most useful when the beam design consists of

several nested coverages, where the combinatorial aspects of

beam overflows (see Section 4.2.3.2.6) become quite

complicated. The payloads to which the new version was applied

had only limited nesting and overflow, so there was not much

loss in the ability of the program to find near-optimal loadings.

Other factors were handled by appropriate data base definitions. For example. U.S./Europe traffic routed to the ISL in

Scenario VI-A used a "psuedo-beam" representing the ISL. with

all European terminals located in the pseudo-beam.

4-33
Ford Aerospace &

Communications Corporation

4.2.3.2 Traffic and Payload Design Optimization

In this section, various concepts used in the design of the

payloads are discussed. These concepts were primarily applied

to the C- and Ku-band payloads, which were assumed to serve

analog traffic; utilization becomes a critical issue when static

switching of transponders must be employed. Some concepts were

applied to other payloads. such as scan area coverages, as well.

4.2.3.2.1 Single Satellite Traffic Loading

Given the total traffic data base and its distribution, one

must decide how traffic will be loaded to a single satellite.

Figure 4.2-14 illustrates two possible approaches. In Approach

1. the total traffic is offered to the "first" satellite.

APPROACH l: SEQUENTIAL LOADING

TO -N- SATELLITES

UTILIZATION

1.0

SKEWED

DISTRIBUTION

OF OVERFLOWS

SAT

1

1

.8

SAT

2

T:62

APPOACH 2: EQUAL LOADING

TO EACH OF "IT

SATELLITES

UTILIZATION

.8

.9

.8

.05

Figure 4.2-14 Loading to a Satellite Constellation

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Ford Aerospace &

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Since this satellite can carry only a fraction of the total

traffic, it is likely that a utilization, or fill factor, of

nearly 1.0 would be achieved. The remaining. or

overflow-traffic, is now offered to the second satellite in the

constellation, and so on until all traffic is loaded. The

problem with this approach is that each overflow has a skewed

distribution relative to the previous one. That is. the first

satellite may carry all of the Seattle-Denver traffic, and the

last satellite is only carrying New York-Chicago traffic.

Approach 2 divides the traffic into N equal partitions, each

with the same distribution, where N is the number of satellites

required to serve the total traffic. N is chosen as the

smallest value which causes no overflows.

An argument can be made that if the total traffic were to be

split among various major carriers or other users. the

distributions would be similar - AT&T's distribution is

probably very close to that of GTE Sprint or MCI. Approach 2

obviously fits this concept better than Approach 1. Another

reason Approach 2 was adopted was that only a single loading is

re.quired. although iteration is required to find the appropriate

value of N. Approach 1 would have required N different loadings, along with multiple traffic data bases.. A different

interconnect plan would have to be developed for each of the N

loadings.

4.2.3.2.2 Traffic/Payload Assignments

Various types of U.S. domestic traffic were defined in

[Ref. 8]. Table 4.2-3 indicates how each traffic type was

assigned.

4-35
Ford Aerospace &

Communications Corporation

Table 4.2-3

Traffic/Payload Assignments

Traffic Type Payload

Trunking

Digital Voice Fixed Ka

Video Conferencing

Channels

Scan Ka Trunking

Data Ku FSS

(1)

Analog Voice Ku FSS with

overflow to C

GPS

Voice + Data +

Video Conferencing

Scan Ka CPS

channels

Broadcast Video (3)

Scenario II

Scenarios V. VI-A. VI-B

Ku FSS and C

C

(2)

(1) In Scenarios V. VI-A. and VI-B. a small amount of thin

route data, assumed to be low rate ( 9.6 Kb/s) was

overflowed to C-band, analog modulation.

(2) Ku beam coverages in these scenarios precluded application

to broadcast video.

(3) See Table XIX of [Ref. 8].

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Ford Aerospace &

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4.2.3.2.3 Effective Reuse

Satellite operators and manufacturers frequently make claims

regarding the number of circuits which a particular spacecraft

can carry. This value is arrived at by multiplying the number

of transponders times the maximum capacity of each. As one

increases the number of beams from a simple CONUS coverage,

where traffic distribution characteristics are not a factor, to

obtain greater reuse, utilization decreases. The effect is

generally of an inverse-square form, as a function of the number

of beams, because the point-to-point traffic is distributed over

a 2-dimensional matrix. Figure 4.2-15 illustrates the effect.

Use of SS/TDMA can alleviate much of the problem, but other

means must be employed for analog modulation. Subsequent

sections will give simple examples to illustrate the concepts.

EFFECTIVE REUSE

"SATELLITE XYZ. THROUGH 100 TIMES REUSE

OF BANDWIDTH. CAN CARRY OVER SEVEN

MILLION SIMULTANEOUS VOICE CIRCUITS."

QUESTION: AT UHAT UTILIZATION WHEN LOADED

WITH A REALISTIC TRAFFIC DISTRIBUTION?

UTILIZATION

AT SATURATION

t.Q

.65 -

2

(CONUS )

NUMBER

OF REUSES

Figure 4.12-15 Effective Re=use

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Ford Aerospace &

Communications Corporation

(1) The Ka-band fixed spots were assumed as given in Volume

II of Western Union Report.

(2) In CONUS. or other broad coverage beams, such as the Ku

coverage for Brazil in Scenario VI-B. the distribution of

traffic is irrelevant.

4.2.3.2.4 Traffic Balancing

An important concept in designing beam coverages is to provide

equal loads in each beam (or. as equal as possible, given beam

separation constraints). If this is not done, then as traffic

with a fixed distribution is loaded, one beam will saturate at a

point where other beams are not fully loaded. These beams will

thus have unused equipment. The more unbalanced the traffic in

various beams, the worse this problem becomes.

Figure 4.2-16 provides a simple example. Each of three

transponders are routed through an SS/TDMA switch. Even though

ASSUMPTIONS: 3 BEAMS. 1 CHANNEL PER BEAM. 1000 CKTS/CHANNEL

SS/TDMA SWITCHING

FREQUENCY PLAN &

SATURATION LOADING

Bl

83

1000

533

467

TRAFFIC:

Bl

B2

B3

Bl

100

800

600

BZ

800

0

0

B3

800

0

100

BEAM

TOTAL

1SOO

800

700

3000

UTILIZATION

(AT SATURATION)

2000

= .67

3000

EFFECTIVE' REUSE IS 2X. NOT 3X

Figure 4.2-16 Traffic Balancing

and Utilization

4-38
Ford Aerospace &

Communications Corporation

the total traffic can. in theory, be carried, the distribution

is such that Beam 1 saturates at a level of 2/3 of the traffic.

The 100 circuits from Beam 3 to itself could also be loaded, but

then the distribution of the traffic carried would be different

than the distribution of the total (see Section 4.2.3.2.1).

Note that traffic balancing applies to an SS/TDMA architecture, because it concerns the total traffic generated by a

beam, and not connectivity between beams, where other problems,

subsequently discussed, can arise.

There were two areas where balancing did not apply in the

payload concepts:

4.2.3.2.5 Connectivity

When static switching is used to interconnect channels of a

given frequency, a common approach to switching on-board. e.g.,

Intelsat-V and most channels in Intelsat-VI. then it is possible

that capacity exists in the beams, but they cannot be interconnected because of the switching arrangement described above.

Figure 4.2-17 illustrates the situation. There is a demand for

1000 circuits (each direction) between Beams 2 and 3. but it is

not possible to interconnect the unused transponder in each of

these beams. The interconnection can be changed to accommodate

the Beam 2 - Beam 3 traffic, but one of the other required

connectivities will be lost.

This problem usually only occurs when one is trying to squeeze

the last few requirements into the loading, so does not cause a

severe problem. Typically, it may reduce the loading by about

5%.

4-39
Ford Aerospace &

Communications Corporation

ASSUMPTIONS: 3 BEAMS. 2 CHANNELS PER BEAM, 1000 CKTS/CHANNEL.

STATIC SWITCHING (3 X 3 PER CHANNEL)

B2) (Bt

©

FREQUENCY PLAN

-FIC:

Bl

B2

B3

Bl

0

1000

1000

B2

1000

0

1000

83

1000

1000

0

BEAM

TOTAL

2000

2000

2000

6000

UTILIZATION

Bl

B2

83

Fl

1000 1

1000

>'

F2

10

1

^

10

00

30

4000

6000

- .67

Figure 4.2-17 Connectivity and Utilization

4.2.3.2.6 Beam Overflows

A very useful technique, when one has nested beam coverages,

is to allow overflows from the smaller beams to those that

"cover" them. Figure 4.2-18 shows how this can be done. Of the

1500 circuits (each way) between Beams 1 and 3. 1000 can be

loaded in Fl transponders. The remaining 500 are then combined

with the 500 circuits between Beams 1 and 2. and loaded in F2

transponders. Those terminals in Beam 3. whose traffic is

overflowed. must operate at Beam 2 frequencies and/or

polarization.

4-40
Ford Aerospace &

Communications Corporation

o ASSUMPTIONS: 3 BEAMS. 2 CHANNEL PER fatAfl. 1000 CKTS/CHANNEL.

STATIC SWITCHING (3 X 3 PER CHANNEL)

-FIC:

Bl

B2

83

Bl

0

500

1500

B2

500

1000

0

B3

1500

0

1000

BEAM

TOTAL

2000

1500

2500

6000

NO OVERFLOW

BI

B2

B3

Fl

1000

t

i 1000

}1000

F2

5000

X

500 )

WITH OVERFLOW

- 83 TO BI - B2)

UTILIZATION

4000

6000

- .67

Bl

B2

83

Ft

1000

1

I 1000

1tooo

F2

1000

1

1000,

1000 '

UTILIZATION

6°°0 . t.o

6000

Figure 4.2.18 Beam Overflows and Utilization'

4.2.3.2.7 Modularity of Capacity

When a static switching connection is made between two beams,

then the entire capacity of the transponders is devoted to

carrying traffic between the two beams. An extreme example

ofthe problem occurs in Scenario VI-A in the "South of the

Border" coverages. Some of the beam- to-beam requirements are

as low as 19 circuits. With assumed transponder capacities of

2800 circuits, a fill factor of less than 1% would result.

One way to alleviate the problem is to split a 36 MHz

bandwidth into two or more sub-bands, each with their own

switching. Another approach is to perform A/D and D/A

conversion on board, and utilize SS/TDMA or BBP to route a

digitized signal, thus providing the advantages of this

architectuare to analog users. Both of these approaches have

been used in our payload concepts where appropriate.

4-41
Ford Aerospace &

Communications Corporation

4.3 SCENARIO II PAYLOAD CONCEPT DEVELOPMENT

4.3.1 General Description

Scenario II consists of medium capacity CONUS (including

Alaska. Hawaii, and Puerto Rico) FSS and medium power DBS

payloads. As shown in Figure 4.3-1. the FSS payload provides

Ka-band (fixed and scanned) Ku-band and C-band coverages. The

DBS payload provides CONUS coverage with two beams, allowing

programming for two different time zones. Figure 4.3-2

summarizes the Scenario II payload.

4.3.2 Institutional and Regulatory Issues for Scenario II

The purposes and priorities are FSS and DBS communications

within the CONUS. The FSS (point-to-point) communications face

intense competition for the long-distance traffic, which was

only -recently the exclusive province of AT&T Long Lines. This

competition is not only from terrestrial circuits. There is

intense competition for orbital positions in applications before

the FCC. By the time that the platform is ready to apply to the

FCC for constructon permits, the available orbital slots in the

C and Ku (FSS) Bands will undoubtedly be assigned. The Ka (FSS)

Bands may also be assigned.

The DBS applications have undergone a change from the initial

concepts of high-powered (200 w.) spacecraft transmitters with

quarter-CONUS beams to 100 w. transmitters with half-CONUS

beams. This change has permitted the incorporation of more

transponders. and the plans to use large spacecraft has

increased the number of transponders (channels) to 16 per

satellite. Since each orbital slot can support only 32 of these

channels, only two of these satellites can be co-located at each

orbital slot. This approach lowers the orbital capacity for DBS

satellites over the CONUS. and will probably increase the

competition for DBS assignments. However, the DBS economic

4-42
Ford Aerospace &

Communications Corporation ORIGINAL PAGE IS

OF POOR QUALfTY

Ku: 100 W PER CHANNEL OF 24 MHz

MEDIUM POWER

C-BAND: 24 CHANNEL OF 36MHz

(1.7 Gb/>)

Kl FIXED: 20 BEAM

38 CHANNEL OF 500 MHz

(38 Gb/i)

Ku: 24 CHANNEL OF 54 MHz

(2.6 Gb/l)

KaSCAN: 6 AREAS

18 CHANNELS OF 240 MHz

14 CHANNELS OF 500 MHz

(23 Gb/l)

POWER: 3.900 warn

MASS: 223kg

COMMUNICATIONS PAYLOAO

OF - 2064kg

12714 watti

POWER: 8814 wira

MASS: 1,841 kg

Figure 4.3-1 Scenario II - Services Allocation

C-BANOs

CONUS S ALASKA L^

-S

CONUS. HAWAII. \Z.

« PUERTO RICO__/^

Ku (FSSI:

CONUS \£.

EAST V^

UEST J-~-

Ku (OBS):

->

uEsT)^

24 CHANNELS

36 nHz 8U

8.5 U

24 CHANNELS

54 HHz 8U

SO W

IE CHANNELS

24 MHz BV

too v

CONUS C

2

fm : T

20

20 BEAMS

PER CHANNEL

1 1 A

2

—

•

?n

\7 i 1

Kl (SCAN): — ^

Y*

CONUS Ti"n*fji

6 AREA SCAN

BEAKS

7.S-7S U

PER CHANNEL

t

•

•

•

6

Figure 4.3-2 Scenario II Overview

4-43
Ford Aerospace &

Communications Corporation

returns remain to be demonstrated. Recent abandonment or

postponement on DBS plans by a number of entrants has cast

doubts on the DBS future, and may lessen competition in this

field.

In order to obtain a suitable orbital position, a current

licensee, or a number of current licensees, of these slot

assignments will have to agree to use their geostationary orbit

slot or slots for a platform. An alternative is to persuade the

FCC to identify an orbital slot for future platform use, and to

make no permanent assignments for this slot. If the case for

the platform could be made strong enough, the FCC could refuse

to renew the current slot assignments and re-assign a slot to

the platform.

The likelihood of the FCC maintaining a spare slot for the

platform, or withdrawing "squatter's rights" from a current

holder of an orbital slot for reassignment to the platform,

appear to be remote. This possibility could change, if the orbit

became so crowded that the platform provided the only viable

solution. However, the current slump in the demand for

satellite capacity, and the possibility of additional spectrum

allocations for satellite communications, indicate that other

solutions will be available. Hence, the most likely prospect is

for one or more of the carriers holding suitable orbital slots,

combining into a Consortium to build and operate the platform.

A financially strong domestic carrier, who holds suitable

orbital slot assignments, could take the lead and incorporate

the payloads of other carriers into the platform.

The dominant carrier would be expected to take the lead in the

following activities:

4-44
Ford Aerospace &

Communications Corporation

1. Obtaining the financing.

2. Obtaining the regulatory approvals from the FCC. Dealing

with the concerns of other satellite carriers who may

oppose the platform concept. Coordinating with other

users of the radio-frequency spectrum who may suffer or

cause harmful interference.

3. Enlisting the participation and support of other carriers

who ace interested in owning a payload on the platform,

and in talcing the lead in clearing away any anti-trust

laws which may preclude such cooperation by carriers.

4. Procuring the spacecraft.

5. Integrating the payloads.

6. Arranging for launch services.

7. Obtaining launch. commissioning. and on-orbit life

insurance.

8. Arranging for tracking, telemetry, and command services.

9. Operating a master control center.

11. Arranging for terrestrial networking

11. Marketing the communications services in cooperation with

the condominium payload owners.

The dominant carrier would need extensive financial resources

("deep pockets") to carry out the activities listed above. The

carrier may also require a partnership with a satellite manufacturer who has the capability and interest in building communications satellite platforms. Such a manufacturer would have

to have successfully built communications satellites in the

past, but not be committed to the "status quo" series of individual communication satellites.

4-45
Ford Aerospace &

Communications Corporation

4.3.3 Summary Antenna Coverages

4.3.3.1 Ka-Band Fixed Spot Beams

The Ka-band fixed beams consist of 20 spot beams, as shown in

Figure 4.3-3. These locations are the same ones used in the "20

Earth Station Model" described in Volume II of the Western Union

Report.

The assignments of various beams to either horizontal or

vertical polarization, shown in Figure 4.3-3, is influenced by

the scan area design discussed subsequently. Any fixed beam

which lies within a scan area of a given polarization must, of

course, be of the opposite polarization. Although one could use

frequency separation between the fixed and scanned beams, doing

POLARIZATION

HORIZONTAL

1

2

5

6

8

9

10

11

14

15

16

17

19

VERT

3

4

7

12

13

18

20

Figure 4.3-3 W.U. 20 Node - Ka Band FSS Scenario II

4-46
Ford Aerospace &

Communications Corporation

so would reduce the effective reuse of the Ka-band spectrum and

hence reduce the total capacity of the design. (The issue of

depolarization is discussed in Section 7.7.)

4.3.3.2 Ka-Band Scan Beams

The Ka-band scan areas are depicted in Figure 4.3-4. A total

of 6 areas were defined, but somewhat differently than previous

concepts. The usual approach has been to set up alternating

bands of opposite polarization. The approach adopted here is

almost the same, except scan areas 3 and 4 constitute a "split"

band.

6V

Figure 4.3-4 Ka-Band 6 Sector Scan Areas

4-47
Ford Aerospace &

Communications Corporation

There were two major reasons which led to this configuration:

1) Fixed Beam constraints

2) Traffic balancing

The 20 fixed beam locations were assumed to be given. The

setting of CPS scan area boundaries is severely constrained by

these fixed beams, as shown in Figure 4.3-5. Normally, one can

achieve a minimum spatial separation between two beams of

identical polarization of about two beam widths (between

centers). As Figure 4.3-5 illustrates, however, when overlaying

a broader coverage, the minimum separation is forced to throe

beam widths because of the overlay boundaries which must be set

between the fixed beams.

• TRAFFIC BALANCING IS DESIRED OBJECTIVE

• SEVERE BOUNDARY CONSTRAINTS IMPOSED BY FIXED BEAM LOCATIONS

H

SCAN AREA SCAN AREA

Figure 4.3-5 CPS Scan Area Design

4-48
Ford Aerospace &

Communications Corporation

These fixed beam constraints make it quite difficult to draw

the scan area boundaries to optimize coverage from a traffic

balancing point of view. a concept discussed in Section

4.2.3.2.4. The total CPS traffic generated within the combined

areas 3 and 4 is almost twice that of the next largest scan

area, yet the fixed beam locations, and the 3-beam width problem

discussed above do not allow setting the scan area boundaries in

that region in any other way.

By splitting this critical area in two. and employing

frequency reuse in each half, at the same polarization, a

significant improvement in traffic balancing is obtained. The

impact of this is that algorithms which generate the scan beam

dwells must ensure that the beams of scan areas 3 and 4 never

simul- taneously dwell along the boundary between the two

areas. Since the traffic levels in Kentucky and Tennessee are

relatively low, this is not a particularly stringent constraint,

4.3.3.3 Ku-Band FSS Beams

The Ku-band FSS coverage is shown in Figure 4.3-6. There are

threp beams. The East and West beams are designed to provide a

BEAM

1

2

3

COVERAGE

CONUS

WEST

EAST

POLOR.

H

V

V

Figure 4.3-6 Ku-Band FSS - Scenario II

4-49
Ford Aerospace &

Communications Corporation

traffic balance. Since traffic can be overflowed to the Ku

CONUS beam (see Section 4.2.3.2.6 for a description of the

concept of beam overflows), then balancing is not critical.

4.3.3.4 C-Band Beams

The C-band coverage is a standard CONUS. including Alaska.

Hawaii, and Puerto Rico, design with polarization (2x) reuse, as

depicted in Figure 4.3-7.

Figure 4.3-7 C-Band FSS -Scenario II

4.3.3.5 Ku-Band DBS Beams

Finally, the DBS coverage consists of two beams, and is identical to the coverages defined for the STC satellite. The issue

of traffic balancing does not apply here because the distribution of "Receive Only" terminals is tranparent to the satellite,

which is operating in a broadcast mode. Figure 4.3-8 shows the

coverages.

4-50
Ford Aerospace &

Communications Corporation

Figure 4.3-8 Ku-Band DBS - Scenario II

Detailed beam contours, based on the reflectors and feed

arrays developed in Task 4. are contained in 5.2.6.2.

4.3.4 Transponder Configurations

4.3.4.1 Ka-Band Trunking

The capacity required to meet trunking requirements must use

both the fixed beams and some portion of the scan beam

capacity. This is required if the design is to provide

connectivity for all assigned trunking traffic. Figure 4.3-9

illustrates that a significant percentage of the trunking

traffic lies outside the fixed Ka spot beams.

The original design developed in Task 3 routed the fixedto-scan traffic through the SS/TDMA switches associated with

the fixed beams to the baseband processor for routing to the

scan beams (and the inverse routing). This design resulted in a

major impact on the size of the BBP (based on 2 bits per Hertz),

and hence an alternate scheme was subsequently developed, as

shown in Figure 4.3-10.

4-51
ORIGINAL PAGE !§

Of* POOR QUALfTY

o

,15

UUtAMM M M U W U M U M M tf M U M S •

sa

4-52
Ford Aerospace &

Communications Corporation

TRUNKING: DIGITAL VOICE + VIDEO CONFERENCING

FIXED Ka + Xt '/. CPS

CPS: VOICE + DATA + VIDEO CONFERENCING

X 2 X CPS

TRUNKING: ANALOG VOICE + DATA

Ku + X 3 X CPS

| OVERFLOU ANALOG VOICE

C

BROADCAST VIDEO: C

Figure 4.3-9 Ka Band Traffic Distribution

In this approach, certain transponders associated with the

scan beams are designed for trunking, and are routed to a scan

beam SS/TDMA switch: programmable frequency shifters are

required with this switch because a given scan beam transponder

may. at different times in the data frame, have to be routed to

different fixed beam switch matrices. Each fixed beam matrix

operates in a single Ka-band 500 MHz channel. This arrangement

is functionally equivalent to the use of a BBP for a trunkinq

application since one does not require circuit level demand

assignment as in CPS. There is a slight loss, due to guard

times, relative to a BBP approach.

There are other aspects to the design which bear mentioning.

Most fixed beams do not use the full bandwidth available. This

is because of widely varying traffic levels generated by each

4-53
Ford Aerospace &

- Communications Corporation

beam if one maintains the distribution of the traffic loaded to

a single satellite the same as the total traffic

distribution(see Section 4.2). Thus, only thirty-eight 500 MHz

transponders are needed, as compared to a theoretical maximum of

100; a significant mass and power saving is the obvious result.

Because the distribution is not uniform, then we can also

adapt the size of the SS/TDMA switches to the traffic. For

example. Fixed .Beams 1 and 2 have sufficient traffic between

them to justify a "hard-wired" connection (see frequency Fl in

Figure 4.3-10). The six beams served by the F2 switch have

enough traffic between them to justify a switch dedicated to

only that traffic. Frequency F5 and its switch provide total

connectivity between all beams.

4.3.4.2 Ka-Band CPS

The overall Ka-band CPS configuration is shown in Figure

4.3-11. Each scan beam provides three 240 MHz channels which

are routed to/from the BBP. with a fourth channel as a spare

(not shown).

The BBP configuration for a single scan beam is detailed in

Figure 4.3-12. It is assumed that, for CPS operation, the data

rate in each 240 MHz channel is 480 Mb/s - based on 2 bits per

Hertz. One channel is divided into four subchannels of 120

Mb/s. two of which can be further divided into four 30 Mb/s

subchannels on an optional basis. The other two subchannels can

operate at either 120 or 60 Mb/s. Also. FEC (forward error

correction) can be selectively provided on the 120/4-30 channels

when required.

A second channel is a dual rate channel which can operate at

either 480 or 240 Mb/s. The third channel is fixed at 480

Mb/s. All downlink channels operate at 480 Mb/s. with selective

FEC.

4-54
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Ford Aerospace &

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The dual rate channels and FEC are intended to provide additional link margin to counter rain attenuation effects. The

lower data rates or FEC are employed only on those dwells

experiencing excessive fading. The scan area with the most CPS

traffic is number three, with 1339 Mb/s (Appendix G.2). Since a

total capacity of 1440 Mb/s is available, there is a 8% margin

(more in other beams) to accommodate reduced throughput due to

fading. Rain distribution statistics indicate that only a very

small percentage of the traffic would be affected at any one

time.

4.3.4.3 Ku-Band (FSS) Configuration

The Ku-band (FSS) configuration consists of eight 54 MHz

transponders in each of the three beams; a 3 x 3 switch provides

connectivity for each channel. At least one of these switches

must be able to operate in an SS/TDMA mode to handle trunking

data which has been allocated to this payload. (See Table

4.2-3.) The overall block diagram is depicted in Figure 4.3-13.

4.3.4.4 C-Band Configuration

Figure 4.3-14 indicates the C-band design, which is a fairly

standard twenty-four channel CONUS configuration. Coverage for

Alaska is provided by the vertically polarized beam, and Hawaii

and Puerto Rico are serviced by the horizontal beam.

No switching is required since CONUS beams provide total

connectivity.

4.3.4.5 Ku-Band (DBS) Configuration

The DBS payload provides eight 24 MHz channels to each of the

two beams. These channels are separated by frequency because

the two beams overlap slightly. The switching arrangement is

4-57
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Ford Aerospace &

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such that one uplink channel can be routed to either one or two

downlinks. This provides the user the flexibility of transmitting different programs to each area at the same time, or a

single program to both areas. Figure 4.3-15 provides the block

diagram for the DBS payload.

4.3.4.6 Frequency Plan and Modulation/Access

Table 4.3-1 provides a description of the Scenario II payloads

regarding frequency usage and the modulation/access methods

assumed to be used.

4.3.5 Traffic Loading

The total traffic loaded to a single Scenario II satellite is

given in Table 4.3-2. The various payload's loading is that at

saturation. and hence correspond to different numbers of

satellites.

A more detailed loading analysis, to the transponder level, is

given in Appendix G.

The maximum throughput, by application, for Scenario II is

given in Table 4.8-4. Based on the above loadings and the

theoretical capacity, utilizations are as follows:

Ka-Trunking .76

Ka-CPS .76

Ku-FSS .62

C .92

Weighted Average .76

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Table 4.3-1

Scenario II Frequency Plan and Modulation/Access

Application

Ka-Trunking

(Fixed +

Scan)

Ka-CPS

Ku-Voice

Ku-Data

Ku-Video

C-Voice

C-Video

Frequency

(GHz)

17.7-20.2

27.5-30.0

(Same as

above)

11.7-12.2

14-14.5

3.7-4.2

5.925-6.425

Xpdr

Bandwidth

(MHz)

500

240

54

36

No. of Modulation/

Xpdr Access

38 Fixed SS/TDMA/

14 Scan 8 Phase PSK

18 SS/TDMA/

QPSK

24 FDMA/CSSB

SS/TDMA/

8-PSK

FM-TV

24 FDMA/CSSB

FM-TV

Notes

(1)

(2)

Ku-DBS 12.2-12.7 24

17.3-17.8

16 FM-TV

(1) See Figure 4.3-10 for frequency/

beam usage.

(2) Each of three channels in a beam is

configured differently.

(See Figure 4.3-12.)

(3) See Table 4.2-3 for traffic/payload

assignments.

4-62
Ford Aerospace &

Communications Corporation

Table 4.3-2

Scenario II Traffic Loading Summary

Corresponding

Application Traffic Carried tt Satellites

Ka-Trunking 1356 K HVC(2) 6.7

+ 2660 video conf. '

Ka-CPS 6565 MB/S 7

Ku 107K HVC 27

+ 200 MB/S data +

(4)

15 Broadcast video

120K HVC 27

(4)

+ 10 Broadcast Video

(1) Assume 0/40 digital - analog split - see section 4.8.6

(2) HVC = "Half Voice Circuit".

(3) 2.1 MB/s per channel - See Table 2.2.7-3.

(4) See Table XIX of [Ref. 8].

4-63
Ford Aerospace &

Communications Corporation

Appropriate conversions, i.e., one half voice circuit equals

24 Kb/s. were made to obtain a common unit of comparison. The

Ku computation of utilization, as an example, is

107K X 24 K + 200M + 15 x 72 M/2.5 = .62.

5184M

3 6 where K=10 and M = 10

4.3.6 Terrestrial System Characteristics

The size of earth station antennas is given for each frequency

band/application in the scenario descriptions of section 3.2.

Modulation and access requirements are listed in Table 4.3-1;

EIRP and G/T characteristics are presented in Section 5. The

remainder of this section discusses any other special

considerations.

Those stations operating in an SS/TDMA mode must be able to

acquire proper synchronization and timing; this includes all

Ka-Band stations, and those with Ku-Band data. Ka-Band tcunking

stations require 960 MB/S modems. and CPS stations must

interface with the orderwire system for control of demand

assignment.

V 4-64
Ford Aerospace &

Communications Corporation

4.4 SCENARIO IV PAYLOAD CONCEPT DEVELOPMENT

4.4.1 General Description

Scenario IV is a medium and high power broadcast satellite.

The high power channels are in the Ku DBS band, and the medium

power channels are in the Ku FSS band, as shown in Figure

4.4-1. Considerable flexibility is provided to the user to

select combinations of uplinking and downlinking programs to the

various beams. Figure 4.4-2 summarizes the Scenario IV payload.

4.4.2 Institutional and Regulatory Issues

Scenario IV presents fewer institutional and regulatory

barriers than Scenario II because the frequency bands are

limited to the Ku FSS and DBS bands. The coverage is restricted

to the CONUS. The intense competition for orbital slots at

C-Band is avoided, and the difficulties involved in obtaining a

construction permit for a communications satellite using 4

frequency bands from a single orbital slot is obviated.

However, the power flux density in the Ku-Band DBS is 6 dB

greater than would be present on Scenario II, and this may

present additional problems on the shared use of this Band.

The 64 channels of direct broadcast television is four times

more channels than proposed on Scenario II. The presence of

this many channels will challenge the alternative television

distribution systems (terrestrial broadcasting and cable

television) more directly. Competition for the programming

sources (television networks, producing studios) will become

more intense. Regulatory agencies (the FCC's Broadcasting

Bureau) will become more involved. The legislative and judicial

branches of the government dealing with copywrite laws will be

drawn into the arguments of how the program originators and

owners should be compensated for direct to home satellite

broadcasting.

4-65
Ford Aerospace &

Communications Corporation

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Ford Aerospace &

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FROM EAST Tx

FROM MTN. Tx RHCP

FROM CNTL Tx

FROM PAC Tx LHCP

HOR'L POL

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TO CNTL BFN

TO PAC BFN

TO ESTN BFN

TO USTN BFN

TO CONUS BFN

Figure 4.4-2 Scenario IV Payload Overview

4-67
Ford Aerospace &

Communications Corporation

The interconnectivity between the FSS and DBS transmitters

would further blur the fuzzy distinctions which now exist

between the two communications services. The power-flux-density

differences of 9 dB may result in two types of TV R/O receiver

terminals on the ground. Widespread deployment of these

terminals may require the adoption of standards for these

receivers by the manufacturers.

In this scenario, a consortium would probably be led by a

broadcaster, a television network, or a movie studio rather than

a communications common carrier. Again, a satellite

manufacturer might be included as a partner because of the

interest in a new line (and concept) of communications

satellites.

A consortium would be expected to perform all the functions

listed previously for Scenario II. but the institutional

barriers would more likely be those addressed by the FCC's

Broadcasting rather than Common Carrier Bureau.

Additional barriers which confront DBS plans include the local

zoning regulation which may keep TV R/O dishes out of suburban

and urban areas. DBS activities in Chicago were restricted by

local zoning ordinances supported by the local cable TV

operators. The FCC has advised local zoning boards that federal

laws could take precedence over local ones, but as yet has

issued no orders to this effect.

The question of scrambling (encoding) video signals will

-affect the future of DBS. Bills have been introduced in Congress

which would prevent cable programmers from scrambling their

signals for the next two years. The eventual effect of

scrambling on the DBS business is uncertain, and may depend on

the cost and availability of the decoders.

4-68
Ford Aerospace &

Communications Corporation

4.4.3 Summary Antenna Coverages

4.4.3.1 Ku-Band FSS Beams

There are three beams available at the Ku FSS band as shown in

Figure 4.4-3. The CONUS coverage beam can be used to provide

programming, using a single channel, where time zone issues are

not critical. and also to address the Central Time Zone

programs. In the latter case, these programs would be received

throughout CONUS. The East Beam can provide Eastern Time Zone

coverage, and the West Beam covers both Pacific and Mountain

Zones. These beams provide some overlap into the East and West

portions of the Central Time Zone respectively.

The basic configuration here is similar to the Scenario II Ku

FSS coverages, except the East and West beams are not skewed to

the Eastr because we are using this band for broadcast rather

than point-to-point traffic.

4.4.3.2 Ku-Band DBS Beams

The Ku-Band DBS beams are shown in Figure 4.4-4; each beam

covers, approximately. one time zone. Beam coverages were set

at about the same size to maintain nearly constant flux

densities in each zone.

4.4.4 Transponder Configuration

Figure 4.4-5 provides a composite block diagram for Scenario

IV. Each of the seven beams (FSS and DBS) contains sixteen 24

MHz channels. The DBS downlinks utilize 200 watts RF, while the

FSS downlinks are SOW. Also, the beam sizes, or coverage area,

of the DBS package are smaller, providing an even higher EIRP

for DBS.

4-69
Ford Aerospace &

Communications Corporation

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ORIGINAL PAGE 83

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Ford Aerospace &

Communications Corporation

A major feature of this scenario is that a great deal of

flexibility is provided to the user for various networking

options. This includes normal time zone differences for

*

programming as well as special situations such as NFL football

broadcasts.

Switching is provided for half the channels in each beam by

eight 7x7 switching matrices; the receivers convert the 14 or

17 GHz uplinks to a common 4 GHz IF frequency for

interconnecton. Also, the switching configuration is different

than a typical satellite RF static switch in that it allows

"1:N" routing. Any one of the switched uplink channels can be

routed to as many as seven downlink channels.

Half the channels in each beam are not switched, and would be

used primarily for local programming.

Table 4.4-1" presents a summary of the frequency plan and

modulation/access methods.

Table 4.4-1

Frequency Plan and Modulation/Access

Application

Ku-FSS

Frequencies

(GHz)

11.7-12.2

14-14.5

Transponder

Bandwidth

(MHz)

24

No.

Transponder

48

Modulation/

Access

FM-TV

Ku-DBS 12.2-12.7

17.3-17.8

24 64 FM-TV

(1) Currently, only one TV channel can be carried in a 24 MHz

transponder. Future developments may allow two channels - for

CATV. Education, etc. [Ref. 8].

4-73
Ford Aerospace &

Communications Corporation

4.4.5 Traffic Loading

Traffic issues are not applicable to this Scenario which

involves direct broadcast only.

4.4.6 Terrestrial System Characteristics

The major distinguishing factor in Scenario IV is. of course,

the very large number of receive only earth stations. A small

number of transmit stations would be required for uplinking the

broadcasts. The size of the Tx/Rx and Rx only stations is given

in Section 3.2

4-74
Ford Aerospace &

Communications Corporation

4.5 SCENARIO V PAYLOAD CONCEPT DEVELOPMENT

4.5.1 General Description

Scenario V is, in many ways, similar to Scenario II, except

that there is no Ku (DBS) payload, and the frequency reuse of

Ku (FSS) and C-Band has been significantly increased. Originally. Scenario V also included a land mobile payload; this was

deleted subsequent to the Task 3 review. Figure 4.5-1 shows the

various coverages. The Ka-band spot and scan beams are identical to Scenario II. An overview of the payload is given in

Figure 4.5-2.

4.5.2 Institutional and Regulatory Issues

Scenario V faces the problems of obtaining an orbital slot

permitting the use of the three FSS Bands over the CONUS. As in

Scenario II. these problems appear so formidable that the

solution may require the participation of licensees holding

suitable slots. Instead of C-Band coverage of the CONUS with a

single beam as in Scenario II. Scenario V uses dual polarization

and four spot beams, two of which overlap in the Northeast.

Similarly, the Ku-Band FSS uses dual polarization and 9 spot

beams, two of which overlap in the Northeast. The Ka-Band FSS

uses 20 small spot beams, plus six separate areas covered by a

scanning spot beam.

This frequency re-use is good for spectrum utilization, but

requires a coordination of dual polarizations in regional areas

which is not currently done, and will need the cooperation of

the current communications satellite owners and users, as well

as the earth station manufacturers to be accomplished.

Obtaining this cooperation and coordination is a formidable

task, and one which could render much of the existing equipment

obsolete. This might require expensive installations of new.

compatible equipment.

4-75
Ford Aerospace &

Communications Corporation

COMMUNICATIONS - 72 Gb/s

C-BAND: 48 CHANNELS OF 36 MHz

(3.5 Gb/s)

KA FIXED: 20 BEAM

38 CHANNELS OF 500 MHz

(38 Gb/s)

KU-BAND: 108 CHANNELS OF 36 MHz

(7.8 Gb/s)

KASCAN 6 AREAS

18 CHANNELS OF 240 MHz

14 CHANNELS OF 500 MHz

(23 Gb/s)

COMMUNICATIONS PAYLOAD

OF-2,261 kg

7,426 watts •

Figure 4.5-1 Scenario V - Services Allocation

4-76
Ford Aerospace &

Communications Corporation

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Communications Corporation

4.5.3 Summary Antenna Coverages

4.5.3.1 Ka-Band Fixed Spot Beams

(Refer to Section 4:3.3.1)

4.5.3.2 Ka-Band Scan Beams

(Refer to Section 4.3.3.2)

4.5.3.3 Ku-Barid FSS Beams

The beam coverages shown in Figure 4.5-3 for Scenario V

Ku-Band are designed to maximize the effective frequency reuse,

given a 15' reflector limit and the assumed traffic

distribution. The 15' limit is based on the shuttle bay

diameter, and the use of the rigid reflector to minimize costs.

These coverages are the result of several iterations; there are

probably further improvements that could be made. but the

overall utilization - see section 4.8.5 - is quite good.

The coverages may. at first glance, seem to be unusual, but

the concepts presented in Section 4.2.3.2 were used

extensively. Although New York has the highest concentration of

traffic, the Midwest (Chicago-Detroit) area proved to be more

difficult to design beam coverages for. This was true in the

Ka-Band scan areas, previously discussed in Section 4.3.3.2. as

well. In New York, one has a "cushion" to the East (in the

Atlantic Ocean), which allows one to obtain two times reuse in

.that area. (See Beam 4H in Figure 4.5-3.) The Midwest also has

a very high traffic level, but it is not possible to provide the

additional full reuse because adjacent areas on both sides must

be covered, and beam width and beam separation factors constrain

the design.

There are a few low traffic areas which are not covered at

all. This traffic was overflowed to C-Band. An alternative

4-78
Ford Aerospace &

Communications Corporation

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design, which was not investigated, would be to provide limited

C/Ku connectivity, thus allowing traffic between Kentucky and

New York, for example, to use C-Band in Kentucky and Ku-Band in

New York.

It should also be noted that the Scenario V concept, as

finally developed, obtained 9 times reuse, instead of the 12

times estimated in Task 2 - see Section 3.2. The latter value

was obtained by deviding the 6° width (satellite field of

view) of CONUS by .45°. However, because of the lower traffic

density in the Western U.S., the reuses would be wasted; thus,

beams 6H and 7V are approximately 3 in width. A higher reuse

was obtained in the Eastern U.S. by splitting beams on a

North/South basis as well as East/West.

4.5.3.4 C-Band Beams

A total of four beams are provided at C-Band in Scenario V. As

in the Ku-Band designs, the maximum reuse possible, relative to

beam separation and traffic considerations, was the goal. A

fifth reuse would have been possible for the West Coast - the

initial design included such a beam but traffic levels do not

justify the equipment. Figure 4.5-4 shows the coverages.

4.5.4. Transponder Configuration

4.5.4.1 Ka-Band Trunklng

(Refer to Section 4.3.4.1)

4.5.4.2 Ka-Band Scan

(Refer to Section 4.3.4.2)

4.5.4.3 Ku-Band

It was not possible to maintain the same Ku Bandwidths used in

4-80
Ford Aerospace &

Communications Corporation

Figure 4^5-4 Scenario V - C-Band FSS Coverage

Scenario II (54 MHz). A maximum of 8 channels would be

available, but there are 9 beams in Scenario V. Because of the

assumption that analog modulation is used (except for a small

amount of trunking data), static switching would result in lack

of complete connectivity. The configuration selected has ten 36

MHz, two 18 MHz. and three 12 MHz channels, each channel

interconnected with a 9x9 switch. The five narrow band channels

were provided to help solve the modularity problem discussed in

Section 4.2.3.2.7. Also, one of the 36 MHz channels must have

an SS/TDMA capability to provide connectivity for data. Figure

4.5-5 shows the configuration.

4.5.4.4 C-Band

Figure 4.5-6 illustrates the C-Band transponder configuration.

Each channel may be interconnected among the four beams by means

of 4x4 switches.

4-81
Ford Aerospace &

Communications Corporation

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4.5.4.5 Freguency Plan and Modulation/Access

Table 4.5-1 provides a description of the Scenario V payloads

regarding freguency usage and the modulation/access methods

assumed to be used.

4-82
Ford Aerospace &

Communications Corporation

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Ford Aerospace &

Communications Corporation

Table 4.5-1

Scenario V Frequency Plan and Modulation/Access

Frequencies Transponder No. Modulation/

Application (GHz) Bandwidth(MHz) Transponder Access

Ka-Trunking

(f ixed+scan)

Ka-Scan

Ku -Voice

Ku-Data

17.7-20

27.5-30

17.7-20

27.5-30

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240

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38

14

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fixed

scan

18.27

SS/TDMA/

8-PSK

SS/TDMA/

8-PSK

PDMA/CSSB

SS/TDMA/8-

C-Voice 3.7-4.2 36 48 FDMA/CSSB

5.925-6.425

C-Video FM-TV

4.5.5 Traffic Loading

The total traffic loaded to a single Scenario V satellite is

given in Table 4.5-2. under the assumption that no broadcast

video channels are loaded, i.e.. Scenario IV satellites carry

all such traffic.

Table 4.5-2

Scenario v Traffic Loading Summary

Cor res pond ingd)

Application Traffic Carried ft Satellites

Ka-Trunking 1356 K HVC(2> +

2660 video Conf.<3) 6.7

Ka-Scan 6565 Mb/s 7

Ku 519 K HVC + 8.8

519 Mb/s data

C 178K HVC 8.8

(1) Assumes 60/40 digital-analog split - see section 4.8.6

(2) HVC = "Half Voice circuit"

(3) 2.1 Mb/s per channel - See Table 2.2.7-3

4-84
Ford Aerospace &

Communications Corporation

Table 4.5-3 contains the loading under the assumption that

broadcast video is carried on the Scenario V satellites.

Table 4.5.3

Scenario V Traffic Loading Summary

(With Broadcast Video)

Appliication

Ka-Trunking

Ka-Scan

Ku

Traffic Carried

1356K HVC <2)+ 2660

video conf. (3)

6565 Mb/s

441K HVC +

400 Mb/s data

95K HVC +

45 Broadcast Video

Corresponding^1)

tt Satellites

6.7

7

11.4

11.4

(1) Assumes 60/40 digital - analog split - see section 4.8.6

(2) HVC: "Half Voice Circuit"

(3) 2.1 Mb/s per channel - see Table 2.2.7-3

(4) See Table XIX of [Ref. 8].

Appendix G contains detailed loadings for the Ka-band payloads,

and Appendix I contains details for the C/Ku payloads.

As in Section 4.3.5. the following utilizations can be derived

for Scenario V (no video):

Ka-Trunking

Ka-Scan

Ku-FSS

C

Weighted Average

.76

.76

.83

.62

.77

4-85
Ford Aerospace &

Communications Corporation

For Scenario V (with video), the results are:

Ka-Trunking .76

Ka-Scan .76

Ku-FSS .71

C .52

Weighted Average .73

4.5.6 Terrestrial System Characteristics

(Refer to Section 4.3.6)

4-86
Ford Aerospace &

Communications Corporation

_

4.6 SCE^AR%3v'rS-A1p'AYLOAD CONCEPT DEVELOPMENT

4.6.1 General Description

Scenario VI-A consists of the Scenario V payloads.

plus a) C-Band coverage of Intelsat gateway stations in

Central and South America and the Caribbean. b) two

intersatellite links and c) a C/L-Band maritime

payload. Figure 4.6-1 summarizes the coverages

provided by Scenario VI-A and Figure 4.6-2 indicates

the payload equipment.

The original concept, presented in Section 3.2. was

to have a complementary pair of satellites (Scenarios

VI-A and VI-B). with Scenario VI-A primarily serving

the Eastern U.S. and Atlantic Ocean Region (AOR). while

VI-B served the Western U.S. and Pacific Ocean Region

(POR). This approach was later modified for several

reasons.

1) Lower U.S. capacity from given orbital arc.

2) High ISL traffic to connect Eastern and Western

U.S.

3) Conflicting design requirements for INTELSAT and

non-U.S. domestic coverage (described in Section

4.6.3.5) .

The current approach to Scenarios VI-A/VI-B is shown

in Figure 4.6-3. Scenario VI-A provides coverage for

all Region 2 international and regional traffic, except

Canada which is covered by VI-B; U.S. traffic could use

either VI-A or VI-B. but for simplicity it was assumed

all of this traffic was on VI-A. The routing of the

traffic, within each satellite, is shown in Figure

4.6-3. For example, circuits from Canada to Brazil are

4-87
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uplinked on Scenario VI-B. crosslinked to Scenario VI-A. and

then downlinked to one of Brazil's gateways. Access for

international/regional traffic in the U.S. and Canada need not

be via gateway earth stations - it is combined with the domestic

point-to-point coverage.

4.6.2 Institutional and Regulatory Issues

Scenario VI-A provides FSS CONUS coverage at C. Ku. and Ka

Bands. FSS C-Band Coverage to Latin America. Maritime Mobile

Satellite Coverage at C and L Bands, and Intersatellite Links to

a European Platform.

The CONUS coverage FSS at C. Ku, and Ka Bands face the same

barriers as discussed in the previous Scenarios. The

international communications introduce a new set of

institutional and regulatory barriers.

The Latin American C-Band coverage constitutes a regional

satellite system. A number of regional satellite systems are in

operation. including Indonesia's PALAPA (which serve some

neighboring countries). the European Telecommunications

Satellite Organization's (Eutelsat's) ECS 1 & 2 (which provides

a wide range of business communications services in Europe).

France's Telecom 1A (which provides service to France and French

territories in the Western Hemisphere, and the Arab Nation's

Acabsat (which will provide voice, data, and video transmission

to Arabian countries). Video signals from U.S. "cable birds"

are received widely in Caribbean and Latin American countries.

The Soviet Union's Intersputnik is a sat.ellite network

interconnecting the Communist Bloc Nations.

Intelsat (a consortium of 109 member nations operating a

global satellite system) has claimed it would be economically

harmed by competition, especially over the heavily-trafficked

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Ford Aerospace &

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Atlantic Ocean. In spite of Intelsat's protests, the current

U.S. Administration has favored competition over monopolies, and

will probably permit increased competition in international

satellite communication. The initial competition will probably

be in video transmission, and in private line service to small

terminals on customer premises. This business should grow

rapidly because it can be offered cheaper than the relatively

high tariffs on Intelsat circuits. (these high tariffs result

mainly from the charges of the Intelsat "signatories." who hold

monopolies in the "Gateway terminals" used in the Intelsat

networks. The Intelsat space segment charges are usually only

10% of the total bill).

With the U.S. determination that separate satellite systems

are in the national interest, the success of the Latin American

regional satellite system reguires the cooperation and

participation of the Latin nations involved. This participation

will probably be forthcoming. because these nations are

interested in better communications systems which can be

provided better by multiple small terminals on customer

premises. rather than reliance on the Intelsat "Gateway

terminal" approach.

In any case, a new set of regulatory and institution barriers

are involved in international communications. The participants

include INTELSAT and the rival satellite systems, the international cable companies and the Intelsat Signatories (who are

usually the government-controlled Postal. Telephone. and

Telegraph "PTT's" in most countries). The Department of State

and its counterparts abroad, are also involved. FCC authorizations are needed for the ground terminals to be located in the

U.S.. and the satellite, if it is to be a U.S. registered

satellite. Authorizations are needed from the PTT's for the

foreign-based ground terminals. The International Telecommunications Union is involved in the assignment of the orbital

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slots. Obviously, coordination with other administrations might

be affected.

These considerations also apply to the inter-satellite link

between the U.S. platform and foreign satellites. The

development and incorporation of these intersatellite links

between regional satellites presents additional competition to

Intelsat and the international cable companies, and they can be

expected to oppose them. However, the ITU has allocated a

number of frequency bands (generally in the millimeter wave

region of the spectrum which does not penetrate the atmosphere)

to the intersatellite service. Intelsat can be expected to

oppose the routing of traffic via intersatellite links between

regional satellites, if that traffic could otherwise be routed

via Intelsat satellites.

The Maritime Payload uses the C&L Bands allocated to the

Maritime Mobil Satellite Service. but. the footprint is

restricted to the Atlantic Ocean and adjoining seas. The

power-flux-density appears higher than available from the

current Inmarsat satellites, and thus can reach smaller, and

less-expensive terminals. If this payload is incorporated into

the Inmarsat System, the institutional barriers are minor. If

this service is proposed as a rival to Inmarsat, then Inmarsat

and the shipping interests who have a vested interest in the

current system can be expected to oppose this competition.

4.6.3 Summary Antenna Coverages

4.6.3.1 Ka-Band Fixed Spot Beams

(Refer to Section 4.3.3.1)

4.6.3.2 Ka-Band Scan Beams

(Refer to section 4.3.3.2)

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4.6.3.3 Ku-Band FSS Beams

(Refer to section 4.5.3.3)

4.6.3.4 C-Band (U.S.) Beams

(Refer to Section 4.5.3.4)

4.6.3.5 C-Band (Regional/International) Beams

A total of nine beams is provided in this payload which cover

all of the Intelsat gateway stations for Central America, South

America, and the Caribbean. Figure 4.6-4 shows the coverages.

The polarizations have been chosen to maximize isolation with

respect to the U.S. C-band beams.

The major reason for placing all of the regional/international

capacity for these areas on one satellite (Scenario VI-A) and

all the domestic coverage on another (Scenario VI-B) is that a

problem, which is essentially the same as the Ka scan area

boundaries vs Ka fixed spot beam issues discussed in section

4.3.3.2, exists here also. The "spot" beams correspond to the

coverage of gateway stations, and the "scan areas" are the

broader coverage required for full domestic service. The

alternative solution would have been to go to very small beam

sizes at C-Band. with the resultant very large antenna. Even

with the small beams, it was apparent that design of coverages

to meet both requirements would have been difficult, if not

impossible.

4.6.3.6 C/L Band Maritime Beams

Figure 4.6-5 illustrates maritime coverage for the Westen

Atlantic provided by a Scenario VI-A spacecraft at 85 W

longitude. To maximize the coverage, the Scenario VI-A should be

positioned well to the East.

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Ford Aerospace &

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Figure 4.6-4 Scenario VI-A - C-Band International FSS Coverage

4.6.4 Transponder Configuration

4.6.4.1 Ka-Band Trunking

(Refer to Section 4.3.4.1)

4.6.4.2 Ka-Band Scan

(Refer to Section 4.3.4.2)

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Ford Aerospace &

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ORIGINAL PAGE IS

POOR QUALITY

Figure 4.6-5 Scenario VI-A - C/L-Band Maritime Coverage

4.6.4.3 Ku-Band (FSS) Configuration

(Refer to Section 4.5.4.3

4.6.4.4 C-Band (U.S.) Configuration

(Refer to section 4.5.4.4)

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4.6.4.5 C-Bahd (Regional/International) Configuration

The distinguishing feature of the Regional/International

payload is the inclusion of baseband processing, in particular

A/D and D/A conversion. It is assumed that the modulation used

by the countries involved is analog, although the larger users

might have some digital circuits on INTELSAT. There are two

primary reasons why conversion to digital is included:

(1) Circuits are routed to/from ISLs or the U.S. Ka-band BBP,

which are assumed to be digital.

(2) The problem of low utilization caused by modular capacity

(see Section 4.2.3.2.7) is particularly severe in this

application.

To expand on the latter area, the traffic involved is very

low. especially between the nine beams; several matrix entries

are as low as 19 HVC. and the average over all 81 possible

entries is only 155 (see Appendix J-2).

In Scenario V. two Ku-Band channels were split into either two

or three subchannels. Although the same approach could have

been used here, A/D + D/A conversion was reguired anyway due to

reason (1) above, so this approach was adopted to provide

subchannelization to counteract low fills.

It should be emphasized that the A/D and D/A conversions are

not equivalent to a transmultiplexor. because the digital

signals generated could not be processed through a D channel

bank or other TDM equipment to recover the individual circuits.

Rather, the digital signal is used only for on-board switching/

routing. in Figure 4.6-6. FDM accesses of different bandwidths

are illustrated; each access is converted to a digital stream of

the appropriate rate (sampling rate times bits per sample). Once

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Ford Aerospace &

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the digital signal is obtained, it can be buffered; on-board

control would then perform framing and synchronization and empty

the buffer at high burst rates through the baseband processor

switch.

7.5

MHz

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Figure 4.6-6 Representative FDM Subchannelization

The overall routing between CONUS (BBP). iSLs. and the LAM/C

processor is shown in Figure 4.6-7. This digital routing switch

provides all of the required connectivities shown in Figure

4.6-3.

4.6.4.6 C/L-Band Maritime Configuration

This payload is representative of an INMARSAT second

generation (125 channel) capability. Figure 4.6-8 illustrates

the basic configuration.

4.6.4.7 Inter-Satellite Links

The ISL assumed for Scenario VI-A is a 60 GHz system, as shown

in Figure 4.6-9. It was assumed that a single channel could

carry two 750 Mb/s streams.

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Ford Aerospace &

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4.6.4.8 Frequency Plan and Modulation/Access

Table 4.6-1 shows the frequencies and modulation/access

methods only for those payloads unique to Scenario VI-A. The

remainder of the Scenario VI-A payloads are identical to

Scenario V. Table 4.5-1.

Table 4.6-1

Scenario VI-A Frequency Plan and Modulation/Access

Frequencies Transponder No. Modulation/

Application (GHz) Bandwidth(MHz) Xpdrs Access

C-Inter- 3.7-4.2 36 108 FDMA/FDM/

national 5.925-6.425 FM

C/L 1.530-1.546 16 (Forward) 1

Maritime 6.425-6.441

1.6265-1.6475 21(Return) 1 SCPC

3.6-3.621

ISL 59.0-64.0 1500 3 TDM/QPSK

4.6.5 Traffic Loading

The single satellite loading for Scenario VI-A is presented in

Table 4.6-2.

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Application.

Ka-Trunking

Ka-Scan

Ku

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ISL

Table 4.6-2

Scenario VI-A Traffic Loading Summary

Traffic Carried

1356K 2660

video conf . (3

6565 Mb/s

519K HVC +

519 Mb/s data

178K HVC

60K HVC +

41 (36 MHz) channels video

158K HVC

Corresponding^1)

ft Satellites

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(2) HVC = "Half Voice Circuit"

(3) 2.1 Mb/s per channel - See Table 2.2.7-3

Appendix J provides detailed loadings for the VI-A specific

payloads; the remainder are covered in Appendices G and I.

Utilizations are as follows:

Ka-Trunk

Ka-Scan

Ku

C(U.S. )

C(LAM/C)

ISL

76

76

83

62

61

84

Weighted Average ,76

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Ford Aerospace &

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4.6.6 Terrestrial System Characteristics

See Section 4.5.6 for the earth station descriptions regarding

the Scenario V payloads which are included as part of VI-A.

The gateway stations used in Latin American/Caribbean (LAM/C)

are assumed to be INTELSAT Standard "A" stations. The maritime

mobile stations are standard INMARSAT-type terminals.

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4.7 SCENARIO VI-B PAYLOAD CONCEPT DEVELOPMENT

4.7.1 General Description

Scenario VI-B consists of the Scenario V payload. less the

C-Band for U.S. coverage. In addition, it provides all domestic

service for Canada. Mexico, and Latin America, including Brazil.

Both Canada and Brazil use a combination of C-and Ku-band to

provide the necessary reuse to meet projected traffic. Also.

Mexico has been assigned two 36 MHz Ku-band channels from the

Scenario V beam 8H (see Figure 4.5-3). which had two unused

channels. This capacity is not necessary to meet year 2008

demand, but the Morales Satellite does provide some Ku capacity.

The addition of this coverage complicates the antenna design, and

may not be worth the extra expense for only two channels. Figure

4.7-1 shows the -services allocation and Figure 4.7-2 summarizes

the Scenario VI-B payload.

4.7.2 Institutional and Regulatory Issues

(Refer to Section 4.6.2)

4.7.3 Summary Antenna Coverages

4.7.3.1 Ka-Band Fixed Spot Beams

(Refer to Section 4.3.3.1)

4.7.3.2 Ka-Band Scan Beams

(Refer to Section 4.3.3.2)

4.7.3.3 Ku-Band (U.S.) Beams

(Refer to section 4.5.3.3)

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4.7.3.4 Ku-Band (Non U.S.) Beams

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Figure 4.7-3 shows three separate Ku-Band coverages. A

single spot beam is provided in the Toronto/Montreal area, and

assumes terrestrial back haul. The concentration of traffic in

this area is very high, and obtainning sufficient reuse at

C-Band only would have been difficult and also required smaller

beamwidths (larger antennas). This spot beam is horizontally

polarized to match the Scenario V Ku Beams 4 and 5 (see Figure

4.5-3) and utilizes spatial separation to obtain frequency reuse.

Figure 4.7-3 Scenario VI-B - Ku-Band Non-CONUS Coverage

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The Mexico beam is also horizontally polarized, and shares the

spectrum with Scenario V beam 8 (two channels). As noted in

Section 4.7.1. this coverage could be eliminated.

Finally. Brazil has complete Ku-band coverage with two times

(polarization) reuse. The demand level, and assumed transponder

capacities, dictated over 3 times reuse, with much of the

traffic concentrated in the Rio De Janeiro - Sao Paulo area. As

in Canada, obtaining the necessary reuse at C-Band only in this

area would have been difficult without going to very large

antennas.

4.7.3.5 C-Band (Non-U.S.) Beams

It was previously mentioned in Section 4.7.1. that U.S. C-band

coverage was dropped from Scenario VI-B. This was due to

provision of C-band coverage for both Canada and Mexico. Canada

is covered by three beams, with an intentional overlap of the

Central and Eastern Beams in the Toronto area - See Figure 4.7-4.

Mexico has two beams, with an overlap in the central portion

of the country (Mexico City. Guadalajara). A Central

America/Caribbean beam is provided. although no traffic

forecasts exist for those areas.

Beam 7 of Figure 4.7-4 provides all necessary coverage for

Venezuela. Columbia. Ecuador, and Peru, with capacity available

for the Northwest portion of Brazil. Beam 8 provides coverage

4.7.3.6 C/L-Band Maritime Beams

"'v

Figure 4.7-5 shows coverage of the Pacific for the Scenario

VI-B platform.

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1 RCP 2 LCP

3RCP

LCP

Figure 4.7-4 Scenario VI-B - C-Band Non-CONUS Coverage

4.7. 4 Transponder Configuration

4.7.4. 1 Ka-Band Trunking

(Refe r to Section 4.3.4.1 )

4.7.4. 2 Ka-Band Scan

(Refer to Section 4.3.4.2)

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Figure 4.7-5 Scenario VI-B - C/L-Band Maritime Coverage

4.7.4.3 Ku-Band (U.S.)

(Refer to Section 4.5.4.3)

4.7.4.4 Canadian Domestic. Regional. and International

Configuration

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•i *. '*

Nine channels in each of the four beams (including the Ku-band

spot) are interconnected via 4x4 switches. Three channels are

processed for routing to the ISLs (see Figure 4.6-3 for the

Scenario VI-B routing scheme). As with the U.S. in Scenario

VI-A, it is possible for an earth station in Canada to have

access to both domestic and international/regional routing,

i.e.. no gateways are required. Figure 4.7-6 illustrates the

payload; it should also be mentioned that the BBP in VI-B

provides connectivity between the two ISLs.

4.7.4.5 Mexico/Caribbean Configuration

As shown in Figure 4.7-7. one half of the channels in each

C-Band beam are connected via 3x3 switches; the other half are

directly connected. as are the two Ku-Band channels. As

previously mentioned, these channels could be deleted because of

the additional antenna complexity.

4.7.4.6 South American Configuration

Figure 4.7-8 illustrates the South American Domestic

configuration. The majority of the capacity of this payload is

to satisfy Brazil's traffic; a total of only 12 of the 60

channels are used for the other countries. As with the Mexico/

Caribbean design, only half of the channels are inter- connected;

C to Ku-Band cross strapping is provided in the six channels.

4.7.4.7 C/L-Band Maritime Configuration

(Refer to Section 4.6.4.6)

4.7.4.8 Inter-Satellite Links

(Refer to Section 4.6.4.7)

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4.7.4.9 Frequency Plan and Modulation/Access

The frequency plan and modulation/access is the same as that

shown previously in Tables 4.5-1 and 4.6-1. with the exception

that the Canadian channels are assumed to be SS/TDMA/8-PSK. and

the Mexico and South American channels are SCPC.

4.7.5 Traffic Loading

Table 4.7-1 contains the single satellite loading for Scenario

VI-B.

Table 4.7.1

Scenario VI-B Traffic Loading Summary

Application

Ka-Trunking

Ka-Scan

Ku (U.S.)

Ku (Non U.S.)

C (Non U.S.)

ISL

Corresponding^)

Traffic Carried

1356K HVC (2) + 2660

video conf.(3)

6565 Mb/s

519K HVC

519 Mb/s data

64K HVC

178K HVC

87K HVC

tt Satellites

6.7

7

8.8

1

1

1

(1) Assumes 60/40 digital - analog split - See Section 4.8.6.

(2) HVC = "Half Voice Circuit"

(3) 2.1 Mb/s per channel See Table 2.2.7-3.

Appendix K contains loading details for the VI-B specific

payloads; the remainder are covered in Appendices G and I.

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Utilizations are as follows:

Ka-Trunking .76

Ka-Scan .76

Ku (U.S.) .83

Ku (Non-U.S.) .81

C (Non-U.S.) .75

ISL .70

Weighted Average .77

4.7.6 Terrestrial System Characteristics

See Section 4.5.6 for the earth station descriptions regarding

the Scenario V payload which are included as part of VI-B.

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4.8 CONCLUSIONS AND RANKING OF SCENARIOS

4.8.1 Conclusions

The basic conclusion reached as a result of Task 3 studies is

that payload concepts, which are optimized relative to traffic

distributon characteristics with high utilization and frequency

reuse, can provide very large capacities from a single orbital

slot.

Regarding U.S. domestic FSS demand, the designs developed

provide more digital capacity than analog (see Section 4.8.6).

This is primarily due to the assumed use of digital modulation

at Ka-band, where there is more bandwidth available.

It has also been demonstrated that the aggregation of payloads

is possible. Such aggregation includes frequency reuse at

C and Ku-band for non-U.S. applications, in conjunction with

high reuse in those bands within the U.S.

A ten satellite network, consisting of a combination of

payload concepts developed, can meet virtually all Region 2,

Year 2008, requirements. The satellite breakdown and traffic

allocation is shown in Table 4.8-1.

Section 4.8.8 provides a quantitative ranking of the

scenarios. A summary of the ranking with the major qualitative

factors for each scenario is shown in Table 4.8-1A.

4.8.2 Bandwidth and Reuse

Table 4.8-2 provides the total bandwidth available at the

various bands foe each scenario. Effective bandwidth was used

(e.g.. 12 transponders at 36 MHz = .43 GHz, instead of .5 GHz).

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Table 4.8-1

Summary of Platform Constellation

Pavload

Number of

Satellites Traffic Served

IV

V

VI-A

VI-B

Notes:

3

3

2

U.S. Broadcast Video

U.S. Domestic FSS

U.S. Domesitc FSS + AOR International

ISL) + Intra-Regional (except Canada)

U.S. Domestic FSS + Non-U.S. Domestic +

Canada (International/Regional) + FOR

International (ISL)

(1) Sparing for U.S. Domestic, included in forecasts.. (See

Section 2.2.1.2.)

(2) In order for seven V/VI Satellites to serve U.S.

Domestic FSS, digital penetration must be approximately

70%. (See Section 4.8.6.)

4.8.3 Efficiency

In order to evaluate the capacity of a given payload relative

to the traffic. one must make assumptions regarding the

modulation and link performance to arrive at the maximum

capacity of a transponder operating in that mode. Table 4.8-3

summarizes the assumptions regarding'these capacities.

4.8.4 Throughput

Tables 4.8-2 and 4.8-3 were combined, along with Tables 4.3-1.

4.5-1. 4.6-1. and Section 4.7.4.9. which delineate the

modulation used for each payload. to give the communications

throughput for each payload in a single platform of each

scenario type (Maritime and DBS not included). Half voice

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Table 4.8-1A

Overall Ranking of Scenarios

1. Scenario V - High Capacity CONUS

Optimized to CONUS distribution

All rigid reflectors

Seven satellite constellation satisfies demand

through 2008

Limited barriers

2. Scenario IV - High Capacity DBS

Single location for multiple users

Minimizes ground assets

FSS payload tailored to DBS

On-board networking

3. Scenario II - Medium Capacity CONUS

Replacement of mid-90's payloads

High capacity digital Ka-band

Poor analog balance for CONUS (92% digital)

No major barriers (orbital location restricted)

4+ Scenario VI-A - International Traffic

Highest throughout Scenario

Lowest utilization/capacity

Major institutional barriers

Suitable for integration with Scenario V and VI-B

4- Scenario VI-B - Non-CONUS Domestic

Efficient use of orbital arc

Extremely difficult institutional barriers

Suitable for integration with Scenario V and VI-A

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Communication

Band

Ka

Ku (FSS)

Ku (DBS)

ISL

Table 4.8-2

Effective Bandwidth (GHz)

II

30.3

1.3

.4

.9

Scenario

IV V

1.2

1.5

3.9

1.7

VI-A

3.9

5.6

4.5

VI-B

30.3 30.3 30.3

5.2

3.

.035 .035

3.0

Table 4.8-3

Summary of Modulation Capacity Assumptions

Modulation Technique

8 PSK

CSSB

FDM/FM

SCPC

Video-FM

SQPSK (ISL)

per ISL channel

Capacity (36 MHz)

72 Mb/s

6000 HVC

2800 HVC

1800 HVC

2.5 Channels

1.5 Gb/s*

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circuits were converted to digital bit rates based on an assumed

24 Kb/s per circuit. Because the capacity assumptions of Table

4.8-3 have been included, the resulting values do not match

previous ones (Figures 4.3-1. 4.5-1. 4.6-1. and 4.7-1) which

were on an assumed 2 bits/Hz basis. Table 4.8-4 provides the

results, as well as a total throughput figure for each scenario.

Table 4.8-4

Maximum Throughput (Gb/s) By Scenario

Scenario

Application

Ka-Trunking

Ka-CPS

Ku-FSS

C

ISL

Total 67 81 93 -85

4.8.5 Utilization

The concept of utilization of communications capacity of a

satellite is somewhat nebulous. The maximum theoretical

throughput depends not only on the number of transponders and

their bandwidth, but also on the modulation/access method

used. Further, one can have a mixture even within the same

transponder; e.g.. two digital voice circuits encoded at 32

Kb/s are equivalent to one circuit at 64 Kb/s. Depending on

whether throughput is measured as a bit rate or in terms of

half voice circuits. different values of throughput are

obtained.

Based on the discussion above, determination of absolute

utilizations is probably not possible. However, one can apply a

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8.

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6.

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9

6

6

9

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49.

8.

15.

14

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9

6

6

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.5

VI-B

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17

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Ford Aerospace &

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consistent definition of utilization to different payloads, and

obtain a relative measure of utilization. This is the approach

used in Sections 4.3.5. 4.5.5. 4.6.5, and 4.7.5. The basic

approach used was to convert all traffic types to a data rate,

using 24 Kb/s per HVC, 2.1 Mb/s per video conferencing channel,

and 29 Mb/s per broadcast channel. C and Ku capa- cities were

calculated based on 6000 HVC per 36 MHz trans- ponder. Table

4.8-5 summarizes the results (exclusive of Scenario IV)).

The overall utilizations for each scenario are very close.

This is due to two major factors:

1. The same Ka-band design was used for all scenarios, and

the capacity at Ka-band is a significant proportion of

the total.

2. Because we are dealing with traffic between many

.terminals, some version of the law of large numbers seems

to apply.

Higher fills in the Ka-Trunking were not attained because of

the modularity factor (see Section 4.2.3.2.7). and the use of

scan beams to carry some trunking traffic. For example, two

500 MHz transponders were assigned to Scan Beam #1 for trunking.

each with an assumed capacity of 40000 HVC. even though only

39.194 circuits were assigned to that beam (see Appendix G).

All but 8000 of these circuits were in fact overflowed from

either Fixed Beams 1 or 9, implying a constraint on the scan

cycle that 75% of the dwell must be on these two positions. By

providing an additional channel, then the time required is only

one-half, or about 38%. The scan cycle must be able to

accommodate both trunking and CPS requirements.

The C-band (U.S) utilization for Scenarios V, VI-A and VI-B

could have been improved with further design iteration. The

overflow from the Ku beams to the C-beams was not as balanced

as anticipated (see Appendix I).

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Table 4.8-5

Summary of Utilization

Application

II

Scenario

VI-A VI-B

Ka Trunking

Ka-CPS

Ku (U.S-FSS)

Ku (Non-U.S.)

C (U.S.)

C (International)

C (Non-U.S.)

ISL

Weighted Average

.76

.76

.62

-

.92

-

-

.76

.76

.83

-

.62

-

-

-

.76

.76

.83

-

.62

.61

-

.84

.76

.76

.83

.81

-

-

.75

.70

.760 .755 .756 .774

4.8.6 Digital/Analog Tradeoffs

The traffic loading results given in Sections 4.3.5 and

4.5.5. regarding U.S. domestic FSS requirements, were in a sense

for the digital/analog ratio (60/40) assumed in Section 2.2.7.

In order to provide a parametric view of the two designs (II and

V) regarding the digital/analog question. Figures 4.8-1 and

4.8-2 were developed. It is emphasized that these two figures

ace for the payload concept for the two scenarios, including the

assumed modulation associated with the individual payloads.

The graphs presented in these two figures show the percent of

total digital traffic (solid lines) served by N satellites, or

percent of total analog traffic (dashed lines) served by N

satellites, as a function of the digital penetration. Points on

the curves whose value is less than 1.0 do not have adequate

capacity to serve all the demand; those over 1.0 have excess

(unused) capacity.

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01

SO)

(O

i.

2.5

2.0 i

1.5

1.0

ANALOG^N8 8

-te 14 '. 6 .'«

Percent Digital

M=9

N=8

N=6-J

Digital

..0

Figure 4.8-1 Scenario II Digital/Analog Tradeoff

The curves can be used in various ways. For example, if we

assume a 60/40 split in the digital/analog ratio, then six

satellites will satisfy the digital demand (with excess

capacity), but will serve only 22% of analog traffic in Scenario

II, and 69% of analog traffic in Scenario V.

Regarding Scenario II, both digital and analog requirements

can be fully met with 9 satellites, but the digital level must

be in the range .87-.95. Scenario V can meet the requirements

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ANALOG

N=9

N=7

N=6

N=5

1.5 '

0.5 .4 .6

Percent Digital

1.0

Digital

Figure 4.8-2 Scenario V Digital/Analog Tradeoff

with only 7 satellites, with digital levels of .68-.74 (see

circled point in each figure).

4.8.7 Qualitative Issues

4.8.7.1 Interference

There are several potential issues in the area of interference

between payloads which would require detailed analysis. An

obvious problem area is an overlap in frequencies, shown in

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Table 4.3-1. between the Ku-DBS uplink and the Ka downlink. The

frequencies given in the table are obtained from ITU Radio

Regulations, as well as FCC filings. The 100 MHz overlap is not

a problem when payloads are in different satellites. Even

though one frequency is an uplink and the other is a downlink,

one cannot transmit and receive at the same frequency on the

same satellite. Hence, the Scenario II frequency plan would

require some modification; e.g.. increasing the Ka-band to

17.8-20.3 (frequencies for satellite fixed service are allocated

from 17.7-21.2).

The large bandwidth available at Ka-band (2.5 GHz) could

produce spurious harmonics at L-band (1.5 GHz) and at the IF

frequency (4 GHz) used in many of the payloads. The adjacent

frequency bands at Ku FSS and DBS are another possible source of

spurious signals. Also, L-band has historically had problems

due to passive intermods (structural effects).

4.8.7.2 Reliability/Availability

A major issue with any large platform with multiple payloads

is to provide very high reliability, especially in the buse.g.. power and attitude control system. From the individual

payload point of view, spare capacity has been provided through

the traffic forecasts (see Section 2.2.1.2) for U.S. domestic

requirements.

The reliability issue for Scenario VI-A and VI-B must be

addressed separately because the payloads which have been added,

over and above the Scenario V U.S. domestic capability, can

service all projected traffic with a single satellite. The

approach proposed in Table 4.8-1 is to provide two each of the

VI-A and VI-B. This is not, from an overall point of view,

supplying 2:1 redundancy, because the U.S. domestic portion of

VI-A and B, which is a large part of tahe total capacity, is

being spared at much less than 2:1. The same argument can be

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made regarding allocation of bus costs to the U.S. domestic and

other payloads.

Figure 4.8-3 shows two possible approaches for sparing VI-A

and VI-B. In Approach A. a single VI-A or B provides all

service (except U.S. domestic requirements). There are two

drawbacks to this approach. First, a complete loss of an active

satellite would result in several hours outage while either the

"spare" is moved, or many customers repointed " their antennas.

Also, moving the spare to preclude non-U.S. users from repointing. will cause U.S. domestic users to repoint. A second

problem is that the larger Intelsat users today try to diversify

their circuits over more than one satellite. In Approach B. if

the satellite linked to the European or Asian platforms has. as

a minimum, its ISL's operating, then a 50/50 split can be

achieved wherein loss of either of the VI-A's (or VI-B's)

maintains connectivity for 50% of the circuits for those

countries requiring such diversity and willing to pay for the

extra earth station. Even if the satellite linked to Europe or

Asia has a total, catastrophic failure, connectivity can be

reestablished (for those who have diversified) by merely

reacquiring the ISL on the remaining VI-A or VI-B.

If ISL capacities could be significantly increased by use of

optical links, then an alternate routing capability would exist;

i.e.. if the AOR link failed. The circuits could be rerouted

via VI-B. the Asian Platform, and finally to the European

Platform.

4.8.7.3 Growth Potential/Flexibility

The growth potential of the payload concepts developed in Task

3 is provided, basically, by addition of satellites as needed;

the traffic loadings performed were to saturation of a single

satellite. In a real system, of course, a satellite would not

instantaneously saturate when launched. A schedule of one

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ORIGINAL PAGE !S

OF POOR QUALITY

VI-AX)

/NON - U.SiS

\ DOMESTIC }

\ + CANADA/

INTERNATIONA^

i+. REGIONAL

APPROACH A

:ISL

INTERNATIONAL

+ REGIONAL

APPROACH R

Figure 4.8-3 Alternative Approaches To VI-A and B Sparing

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' '-' •"< -'->:', f'r.f Xlv.

VTI.jv'ii!,;'} .300^ Relaunch per year, or slightly longer, would meet the projected

growth. 1998 to 2008. for the heaviest demand - U.S. domestic.

Certain payloads have the flexibility to operate in different

modulation/access schemes; others are not as flexible. For

example, the C/Ku transponders have many options regarding how

they are used, but the Ka transponders must use SS/TDMA. would

allow analog transmission, but with only five (maximum) FDM

channels and 26 beams (including scan beams). providing

connectivity would be impossible. Smaller bandwidth channels

could be used. but at the cost of many more physical

transponders.

The Scenario VI-A coverages of LAM/C have considerable spare

capacity, thus allowing for flexibility. The Scenario VI-B

domestic coverages do not have nearly as much spare capacity,

although Approach B. described in Figure 4.8-3. wherein both

Scenario VI-B satellites are active, would provide additional

flexibility. In this case a higher outage would occur in the

event of complete failure of one of the Scenario VI-B satellites.

4.8.7.4 Complexity

The payloads defined in Task 3 are. in large part, scaled from

existing technology. For example, the Scenario V Ku-band beam

forming network (9 beams) is not significantly more complicated

than an Intelsat-VI BFN (6 beams), although the fairly close

tolerances on beam separation used in Scenario V do complicate

the design and manufacture processes.

The highest risk area is considered to be the on-board processing; i.e.. base band processor. SS/TDMA. scan beams, and the

control of these entities. Although the NASA ACTS satellite

will demonstrate feasibility of these systems, the payloads

using on-board processing designed in this study yield an order

of magnitude increase in size and complexity.

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4.8.8 Ranking

Table 4.8-6 summarizes the overall ranking of each scenario

for the various payload concept evaluation criteria. The

overall ranking was obtained by simply adding the rankings in

each category, rather than using weighting factors. The same

approach was used in the ranking by aggregation criteria in

Section 3.

Table 4.8-6

Ranking of Payload Scenarios

Payload Concept Scenario

Criteria

Bandwidth-Reuse

Modulation Efficiency 4

Interference

Reliability/

Availability

Growth

Complexity

Utilization

Total

Ranking 32 1 4+4 -

There is one entry in Table 4.8-6 which was included to provide

a consistent comparison, the utilization for Scenario IV. One

can argue that 100% utilization is probably not possible: e.g..

if a single uplink is switched to more than one downlink beam

area, then some uplink capacity will be unused. The value chosen

here was simply the average of the utilization of the other four

scenarios.

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II

4

4

2

2

2

2

4

20

IV

5

5

1

1

1

1

3

17

V

3

1

3

3

1

3

2_

16

VI -A

1

2

4

4

1

5

5_

22

VI-B

2

3

5

5

2

4

1

22
Ford Aerospace &

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SECTION INDEX

Page

5.0 PAYLOAD DEFINITION (TASK 4) 5-1

5.1 OVERVIEW 5-1

5.1.1 Scope of Payload Definition 5-1

5.1.2 Weight and Power for All Scenarios 5-2

5.1.3 Weight and Power of Payloads used in Scenarios 5-4

5.1.4 Approach to Pavload Definition Development 5-5

5.2 SCENARIO II DEFINITION 5-14

5.2.1 Introduction 5-14

5.2.2 C-Band FSS Payload 5-20

5.2.2.1 Overview 5-20

5.2.2.2 Antenna 5-24

5.2.2.3 Transponder 5-34

5.2.2.3.1 6/4 GHz Receiver 5-35

5.2.2.3.2 Input Multiplexers . 5-37

5.2.2.3.3 SSPA(8.5 Watt) 5-39

5.2.2.3.4 Output Multiplexers 5-40

5.2.2.3.5 Preselection Harmonic Filters 5-41

5.2.3 Ka-Band FSS Pavload 5-42

5.2.3.1 Overview 5-42

5.2.3.2 Antenna 5-43

5.2.3.3 Transponder 5-49

5.2.3.3.1 30/4 GHz Receiver 5-50

5.2.3.3.2 Input Multiplexer 5-52

5.2.3.3.3 Dynamic IF Switch Matrix 5-52

5.2.3.3.4 4/20 GHz Upconverter 5-55

5.2.3.3.5 75 W TWTA 5-56

5.2.3.3.6 Output Multiplexers 5-57

5.2.3.3.7 Preselection Harmonic Filters 5-58

5.2.3.3.8 Programable Frequency Shifters 5-58
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SECTION INDEX (Cont.)

Page

5.2.4 Ka-Band Scan Payload 5-58

5.2.4.1 Overview 5-58

5.2.4.2 Antenna 5-62

5.2.4.3 Transponder 5-68

5.2.4.4 Baseband Processor 5-70

5.2.5 Ku-Band FSS Payload 5-74

5.2.5.1 Overview 5-74

5.2.5.2 Antenna 5-74

5.2.5.3 Transponder 5-84

5.2.5.3.1 14/11 GHz Receiver 5-85

5.2.5.3.2 Input Multiplexer 5-87

5.2.5.3.3. RF Switch Matrix 5-88

5.2.5.3.4 12 GHz Driver Amplifier 5-88

5.2.5.3.5 50 Watt TWTA 5-89

5.2.5.3.6 Output Multiplexer 5-89

5.2.5.3.7 Preselect/Harmonic Filters 5-90

5.2.6 Ku-Band DBS Payload ; 5-91

5.2.6.1 Overview - 5-91

5.2.6.2 Antenna 5-91

5.2.6.3 Transponder 5-99

5.2.6.3.1 17/4 GHz Reciever 5-100

5.2.6.3.2 Input Multiplexer 5-102

5.2.6.3.3 RF Switch Matrix 5-102

5.2.6.3.4 Up Converter 5-102

5.2.6.3.5 100/200 Watt TWTA 5-104

5.2.6.3.6 Output Multiplexer 5-105

5.2.6.3.7 Preselect/Harmonic Filters 5-105

5.3 SCENARIO IV DEFINITION 5-106

5.3.1 Introduction 5-106

5.3.2 Ku-Band FSS Payload 5-111

5.3.2.1 Overview . 5-111

5.3.2.2 Antenna 5-114
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SECTION INDEX (Cont.)

Page

5.3.2.3 Transponder 5-121

5.3.2.3.1 14 GHz/4 GHz Receiver 5-122

5.3.2.3.2 4 GHz Input Multiplexer 5-124

5.3.2.3.3 R.F. Switch Matrix 5-124

5.3.2.3.4 4/11 GHz Upconvertor 5-124

5.3.2.3.5 11 GHZ - 50 Watt TWTA 5-125

5.3.2.3.6 11 GHz Output Multiplexer 5-125

5.3.2.3.7 Pre-Select and Harmonic Filter 5-125

5.3.3 Ku-Band DBS Payload 5-125

5.3.3.1 Overview 5-125

5.3.3.2 Antenna 5-128

5.3.3.3 Transponder 5-135

5.3.3.3.1 17/4 GHz Receiver 5-136

5.3.3.3.2 4 GHz Multiplexer 5-136

5.3.3.3.3 4/12 GHz Upconverter 5-136

5.3.3.3.4 12 GHz - 200 Watt TWTA 5-137

5.3.3.3.5 12 GHz Output Multiplexer 5-137

5.3.3.3.6 Pre-Select and Harmonic Filters 5-137

5.4 SCENARIO V DEFINITION 5-138

5.4.1 Introduction 5-138

5.4.2 C-Band FSS Payload 5-142

5.4.2.1 Overview 5-142

5.4.2.2 Antenna 5-145

5.4.2.3 Transponder 5-155

5.4.2.3.1 6/4 GHz Receiver 5-156

5.4.2.3.2 4GHz Input Multiplexer 5-156

5.4.2.3.3 RF Switch Matrix 5-156

5.4.2.3.4 4GHZ 8.5 watt SSPA 5-156

5.4.2.3.5 4 GHz. Output Multiplexer 5-156

5.4.2.3.6 Pre-Select and Harmonic Filters 5-156

5.4.3 Ka-Band FSS Payload 5-157

5.4.4 Ka-Band Scan Payload 5-157
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SECTION INDEX (Cont.)

Page

5.4.5 Ku-Band FSS Payload 5-157

5.4.5.1 Overview 5-157

5.4.5.2 Antenna . 5-159

5.4.5.3 Transponder 5-174

5.4.5.3.1 14/11 GHz Receiver 5-175

5.4.5.3.2 11 GHz Input Multiplexer 5-175

5.4.5.3.3 RF Switch Matrix 5-175

5.4.5.3.4 11 GHz Power Amplifiers 5-175

5.4.5.3.4.1 11 GHZ SSPA. 5 Watt 5-176

5.4.5.3.4.2 11 GHZ SSPA 10 Watt 5-177

5.4.5.3.4.3 11 GHZ SSPA 20 Watt 5-178

5.4.5.3.5 11 GHz Output Multiplexers 5-180

5.4.5.3.6 Pre-Select and Harmonic Filters 5-180

5.5 SCENARIO VI-A DEFINITION 5-181

5.5.1 Introduction 5-181

5.5.2 C-Band FSS Payload 5-188

5.5.3 C/L Band Maritime Payload - Western Atlantic 5-188

5.5.3.1 Overview 5-188

5.5.3.2 Antenna 5-192

5.5.3.3 Transponder 5-192

5.5.3.3.1 Maritime C/L Receiver 5-196

5.5.3.3.2 Maritime L-Band Power Amplifier 5-198

5.5.3.3.3 Pre-Select. Harmonic and BP Filters 5-200

5.5.3.3.4 Maritime L/UHF Receiver 5-200

5.5.3.3.5 Maritime UHF/4 GHz Upconverter 5-203

5.5.3.3.6 C-Band Power Amplifier 5-204

5.5.4 C-Band FSS International Payload 5-205

5.5.4.1 Overview 5-205

5.5.4.2 Antenna 5-205

5.5.4.3 Transponder 5-222

5.5.4.3.1 6/4 GHz Receiver 5-223

5.5.4.3.2 4 GHz Input Multiplexer 5-223
Ford Aerospace &

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SECTION INDEX (Cont.)

Page

5.5.4.3.3. RF Switch Matrix . 5-224

5.5.4.3.4 4 GHZ 8.5 Watt SSPA 5-224

5.5.4.3.5 4 GHz Output Multiplexer 5-224

5.5.4.3.6 Pre-Select and Harmonic Filter 5-224

5.5.4.4 Baseband Processor 5-224

5.5.5 Ka-Band FSS Payload 5-230

5.5.6 Ka-Band Scan Payload 5-230

5.5.7 Ku-Band FSS Payload 5-230

5.5.8 60 GHz Inter-Satellite Link 5-230

5.6 SCENARIO VI-B DEFINITION 5-234

5.6.1 Introduction 5-234

5.6.2 C/L Band Maritime Payload - Eastern Pacific 5-240

5.6.2.1 Overview 5-240

5.6.2.2 Antenna . 5-240

5.6.2.3 Transponder 5-243

5.6.3 C-Band Non-CONUS. FSS Payload 5-243

5.6.3.1 Overview 5-243

5.6.3.2 Antenna 5-246

5.6.3.3 C-Band Transponder 5-262

5.6.3.3.1 6/4 GHz Receiver 5-263

5.6.3.3.2 4 GHz Input Multiplexer 5-264

5.6.3.3.3 RF Switch Matrix 5-264

5.6.3.3.4 4 GHz 8.5 Watt SSPA 5-264

5.6.3.3.5 4 GHz Output Multiplexer 5-264

5.6.3.3.6 Pre-Select and Harmonic Filters 5-264

5.6.3.4 Baseband Processing 5-264

5.6.4 Ku-Band Non-CONUS FSS Payload 5-266

5.6.4.1 Overview 5-266

5.6.4.2 Antenna 5-270
Ford Aerospace &

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SECTION INDEX (Cont.)

Page

5.6,4.3 Ku-Band Transponder 5-270

5.6.4.3.1 Ku-Band Receiver 5-276

5.6.4.3.1.1 14/11 GHz Receiver 5-276

5.6.4.3.1.2 14/4 GHz Receiver 5-276

5.6,4.3.2- Input Multiplexers 5-276

5.6.4.3.2.1 11 GHz Input Multiplexers 5-276

5.6.4.3.2.2 4 GHZ Input Multiplexers 5-276

5.6.4.3.3 RF Switch Matrix 5-277

5.6.4.3.4 4/11 GHz Upconverter 5-277

5.6.4.3.5 11 GHZ SSPAs 5-277

5.6.4.3.6 11 GHz Output Multiplexers 5-277

5.6.4.3.7 Pre-Select and Harmonic Filters 5-277

5.6.5 Ka-Band FSS Payload 5-277

5.6.6 Ka-Band Scan Payload 5-277

5.6.7 Ku-Band FSS Payload 5-277

5.6.8 60 Ghz Inter-Satellite Link 5-278
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5.0 PAYLOAD DEFINITION (TASK 4)

5.1 OVERVIEW

Based on the NASA selected system concepts and the modifications

made to the original scenario aggregations, the five selected

scenarios were then developed in this Task 4 to define the space

segment hardware to the component level. In this section each of

'the payloads will be categorized to Launch Concept 1 or 2.

5.1.1 Scope of Task 4 - Payload Definition

The purpose of Task 4 of this study is to define payload system

configurations and corresponding technical characteristics for the

payload concepts and architectures developed in Task 3 subject to

NASA-furnished constraints imposed by spacecraft/transportation

system capabilities.

Two launch concepts were considered:

o Launch Concept ttl - Up to a maximum single shuttle launch

of combined spacecraft and upper stage with a spacecraft

weight of up to 12.000 pounds (5443 kg.).

o Launch Concept tt2 - Allows a separate spacecraft (without

upper stage) of size and weight up to a full shuttle launch

capability of 65.000 pounds (29.484 kg).

The report section includes descriptions of the five selected

scenario payload configurations. their corresponding technical

characteristics. and the requirements that they impose on the

spacecraft, transportation, and space operation systems. Detailed

descriptions of transponder and antenna elements. as well as

baseband processor where applicable, are included together with

weight, power, and volume characteristics.

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The impact of emerging (low risk) and projected 1994 (high

risk) technology on the payload characteristics is identified.

5.1.2 Weight and Power for All Scenarios

Table 5.1-1 provides a summary of the weight and power for

Scenarios II. IV and V, and Table 5.1-2 is the same for Scenarios

VI-A and VI-B. Included in the estimates are the coax,

waveguide. and harness interconnects. plus an estimate for

integration hardware to put the components together and provide

necessary brackets for support and mounting. Not included are

any structure or satellite mounting hardware such as between the

feed and reflector. Both tables are based on projected (high

risk) technology. It is anticipated that Table 5.1-1 payload

could fit launch concept 1 and Table 5.1-2 payloads would fall

into launch Concept 2. Table 5.1-2 payloads would also require

some LEO assembly due to the number of reflectors.

Table 5.1-1

Characteristics of Scenario Payloads Using Projected Technology

(Integration Hardware Included)

PAYLOAD

C-Band FSS

Scenario II Scenario IV Scenario V

Wt(kg) Pwr(W) Wt(kg) Pwr(W) Wt (kg) Pwr(W)

89 659 246 708

Ku-Band FSS 261 2522 605 5075 523 785

Ku-Band DBS 223 3876 1012 29960

Ka-Band 1492 5933 1492 5933

TOTAL SCENARIO 2065 12990 1617 35035 2261 7426

5-2
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Table 5.1-2

Characteristics of Scenario Payloads Using Projected Technology

(Integration Hardware Included)

PAYLOAD

C-Band FSS(Domestic)

C-Band FSS(Int'l)

C-Band FSS(Non-CONUS)

Scenario VI-A

Wt(kq) Pwr(W)

246

750

708

2166

Scenario VI-B

Wt (kg) Pwr(W)

574 1903

Ku-Band FSS(CONUS)

Ku-Band FSS(Non-CONUS)

523 785 523

186

785

1796

Ka-Band FSS(CONUS) 1492 5933 1492 5933

Maritime 79 649 44 649

Inter Satellite Links 111 160 107 131

TOTAL SCENARIO 3201 10401 2926 11197

5-3
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5.1.3 Weight and Power of Payloads used in Scenarios

Table 5.1-3 provides a summary of the weight and power required

by each of the 16 different payload elements used in the five

Scenarios based on projected (high risk) technology. Table 5.1-4

is the same breakdown using emerging (low risk) technology. Use

of the low risk technology would make Scenario V and possibly

Scenario II exceed the single shuttle to GEO capability without

fuel servicing or augmented perigee boost.

Table 5.1-3

Weight and Power of Payload Elements Using High Risk Technology

Payload Element

C-Band FSS(2 x reuse)

C-Band FSS(4 x reuse)

C/L Band Maritime

C/L Band Maritime

C-Band Intn'l(9 x reuse)

C-Band Non-CONUS(9 x reuse)

Ku-Band FSS(3 x reuse)

Ku-Band FSS(3 x reuse)

Ku-Band FSS(9 x reuse)

Ku-Band Non-CONUS

Ku-Band DBS(no reuse)

Ku-Band DBS(4 x reuse)

Used in

Scenarios Weight(kq)

II

V. VI-A

VI -A

VI-B

VI-A

VI-B

II

IV

V. VI-A. VI-B

VI-B

II

IV

89

246

79

63

750

574

.261

605

523

186

223

1012

Power(Watts)

659

708

649

649

2166

1903

2522

5075

785

1796

3876

29960

Ka-Band FSS(CONUS) II. V. VI-A. VI-B 1492 5933

60 GHz Inter-Sat

60 GHz Inter-Sat

VI-A

VI-B

111

107

160

131

5-4
Ford Aerospace &

Communications Corporation

Table 5.1-4

Weight and Power of Payload Elements Using Low Risk Technology

Payload Element

C-Band FSS

C-Band FSS

C/L Band Maritime

C/L Band Maritime

C-Band International

C-Band Non-U.S.

Ku-Band FSS

Ku-Band FSS

Ku-Band FSS

Ku-Band Non U.S.

Ku-Band DBS

Ku-Band DBS

Ka-Band FSS

Ka-Band Scan

60 GHz Inter-Sat

60 GHz Inter-Sat

Used in

Scenarios Weiqht(kq) Power(Watts)

II

V. VI-A

VI -A

VI-B

VI-A

VI-B

II

IV

V. VI-A. VI-B

VI-B

II

IV

II, V, VI-A. VI-B

II i V. VI. VI-B

VI-A

VI-B

121

327

105

63

987

745

315

751

812

301

278

1227

2007

2007

147

140

922

100-1

855

855

3140

2704

3444

7052

1164

2751

4554

34060

6849

6849

285

224

5.1.4 Approach to Payload Definition Development

To accomplish the payload definition Ford Aerospace utilized

the approach of "top-down system engineering" methodology

complemented with multilevel tradeoff analysis and iterations.

This encompassed the following key activities: '

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o Analyze payload requirement to identify key issues and

design drivers.

o Allocate functions to ensure compliance with system

constraints envelope and requirements.

o Establish performance budgets/trades to optimize

utilization of plant in place and technology forecasted

in 1998.

o Generate baseline payload definitions to assess

alternative approaches/options as appropriate.

The "top-down system engineering" ensures that payload concept

definitions are logically synthesized. Multilevel trade

analyses, with iterations as required, ensures that impartial

consideration of all NASA concepts and assets applicable to this

study as well as new technology forecasted are integrated into

the overall system design. This results in an end payload

definition for each concept that is cost _ effective, capable of

growth, and resilient to various operational and failure modes.

For each payload concept, a payload configuration is derived in

terms of antenna placement and deployment and other electrical,

mechanical. and structural characteristics; transponder

characteristics; and onboard processing characteristics. The

configurations were developed as a total system, with due

consideration to the bus interface characteristics and other

constraints.

Antenna. The design of a satellite antenna system has

undergone drastic changes since the advent of communication

satellites. Such designs will continue to change with new

requirements for advanced antenna systems. including those

associated with the advent of digital signal processing and new

devices such as MMICs and solid-state power amplifiers.

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Ford Aerospace &

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The major challenges in antenna design and development ace:

(1) greater antenna aperture size. (2) wider frequency bandwidth

capability. (3) faster pattern reconfiguration, and (4) greater

pattern control. A large antenna aperture of several hundred

wavelengths size allows high concentration of limited radiated

power onto small regions of the earth to provide a highly shaped

beam. This also enables the formation of several simultaneous

beams for frequency reuse and reduces potential interference

between beams and satellites. A highly shaped beam increases

EIRP. thus reducing the amount of power required from a spaceborne TWT or SSPA. and reduces the required earth terminal

antenna size. A multiple-beam antenna (MBA) system greatly

increases the communication system capacity. Better pattern

control reduces sidelobes and thus improves the signal-to-noise

ratio (SNR) in a given MBA system, and also allows a greater

number of satellites to be placed in synchronous orbit. Wider

frequency bandwidth also increases system capacity. Pattern

reconfigurability permits implementation of TDMA systems and

pattern nulling.

A large antenna aperture poses problems in pattern control,

feed and beam-forming network design, test and evaluation, and

space-craft integration. Scan aberrations are increased as the

scanning beams scan a greater number of beamwidths away from the

antenna axis. A large antenna aperture also increases integration problems on a space-limited spacecraft and requires a

greater number of feeds, which implies more power divider network

components and further challenging design problems such as

beam-forming network layout, size, and weight. Such increased

complexity also results in requirements for added testing during

breadboard development and space-qualification phases.

The ultimate capacity of a communication satellite is limited

by the available frequency bandwidth. The demand for wideband

data and video teleconferencing will saturate the existing lower

frequency band capacity. Higher frequency bands such as Ka-band

or higher will be needed. As the operating frequency increases.

5-7
Ford Aerospace &

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the size of feed elements and beam-forming network components

decreases and the number of components and their total loss will

increase accordingly. Faster pattern reconfiguration and pattern

control increases the complexity in the design of switching and

control components - variable power dividers and variable phase

shifters. The advances in digital data processing and new

devices, such as SSPA and MMIC. will revolutionize the design

concepts and implementation of future advanced satellite antenna

systems such as those considered in this study.

The problems addressed above involve three major design areas

for a satellite antenna system:

a. Optical Design - may involve a specially shaped

reflector/lens, phased array or combination. or a

microstrip antenna.

b. Feed Array - may involve possibly hundreds or thousands

of individual elements to properly illuminate the

optical aperture for multiple or scanning beams.

c. Beam-Forming Network - involves microwave distribution

and control devices designed to excite individual

elements of the feed array, as well as frequencyselective surfaces (FSS) used as spatial filters for

multifrequency bands. SSPA or MMIC will be used to

compensate for BFN losses and provide the required EIRP

in an active antenna system.

The optical problem involves the design of an optical system,

such as reflector, lens, phased array, or microstrip antenna, to

allow positioning of a narrow fixed or scanning beam anywhere

within a field of view. One of the current MBA concepts requires

the formation of 10 to 100 pencil beams, each fully reusing a

common frequency band and all emanating from a single large

antenna aperture. Another application requires 16 simultaneous

beams to be electronically steered over a ±30° field of view.

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The shape of each beam must be varied to provide the gain required

to accommodate system specifications.

The key to the successful design of such systems is the choice

of a good optical system. A reflector antenna system has been

the first choice because of its simplicity and design maturity.

A lens antenna system is generally heavy for low-frequency-band

operation. Higher frequency operation might make a lens system

attractive for a future satellite antenna system. A phased

array, or microstrip antenna, requires a complex BFN. Its use

will be highly dependent on low-cost design, development, and

fabrication techniques, and/or the design maturity of SSPA or

MMIC. The use of larger aperture reflectors larger than the 15

ft diameter of the STS will lead to unfurlable reflectors and

interface problems with the large, low-frequency, flexible body

interaction with the control system.

The feed array problem involves the types of feed elements,

feed configuration, and interface with BFN. The feed elements

may be large multimode horns, arrays of small horns, or other

structures, properly combined in clusters to produce the desired

beams, but flexible enough to allow close spacing and finite

control of adjacent beams.

The BFN problem involves design of a microwave network with

minimum loss and adequate flexibility to excite the individual

feed elements with proper amplitudes and phases to form the

desired shaped beams or multiple beams, and to reconfigure beams

or switch beams as required. With advances in electronic

technology and signal processing, analog information such as

amplitude and phase may be converted into digital form and

computer-controlled by an on-board microprocessor. Such digital

beam-forming networks with SSPA or MMIC components will

definitely add a new dimension and pose new design problems in

future satellite antenna systems.

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Each problem individually influences the design of a satellite

antenna system. System optimization is required to select the

best combination of solutions to achieve not only the desired

performance but also low cost and low risk for the whole system.

i Table 5.1-5 summarizes this discussion and presents the required

technology development and risks at each phase.

Table 5.1-5.

Evolution of Satellite Antenna System Technology

1960s

1960-70S

1970-SOs

1980-90S

1980S +

Antenna

Concept

Simple beam

Key

Components

Antenna,

connectors

Shaped beam Reflector

Reconfigure,

able over

space

Reconfigureable over

channels

VPD/VPS.

reflector,

lens, BFN

components

Gridded

reflector,

shaped

reflector,

dual reflector, high

frequency

BFN components. FSS

Required

Technology

Development

Light weight

space-qualified material

Frequency

reuse, wider

bandwidth

Reconfigure- MMIC.

able over

time

BFN control- High speed

ler. large

aperture

optics

Risks

Reliability

Reliability

Reliability

Computer

aided design,

high frequency VPD/

VPS. switches,

SSPA. reflector tolerance

MMIC

Reliability

computation,

wide angle

scanning

optics,

optics tolerance, high

frequency

wideband or

multiband

BFN components

Feasibility,

COSt.S

reliability

5-10
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RF Transponder. The1 RF transponders for the payload concepts

are defined and developed in block diagram form. For each

payload. alternative RF transponder configurations were

identified to serve as the basis for trade studies. These

configurations utilize the forecasted 1998 RF transponder

technology. Where applicable, provisions for in-orbit deployment, repair or testing at Space Station were considered. This

in-orbit servicing capability will be considered in arriving at

the chosen payload implementations.

Trade studies of the alternative configurations were made,

based on their flexibility. growth potential. reliability,

technical/economic risks, size, weight, and power. The selected

configuration for each payload concept then then further

developed in block diagram form. These configurations were then

expanded in sufficient detail to identify the number of

transponders, their frequency plan, interconnectivity. and

redundancy implementation to achieve the desired reliability.

The block diagrams were developed to the component level

(receivers, filters, switches, filters, amplifiers, etc.) to aid

in assessing the required volume, weight, and power requirements.

On-board Processing. In the definition of payload concepts/

architectures for a given service aggregation scenario, performance requirements for on-board processing were developed. By

matching the onboard processing technology data base to the

performance requirements developed in Task 3, the hardware

necessary to support a given architecture was estimated.

Trade studies of the alternative configurations were made based

on their flexibility, growth potential, reliability, technical/

economic risks, size, weight, and power. The selected configuration for each payload concept was then further developed in

block diagram form. These configurations were then developed

5-11
Ford Aerospace &

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in sufficient detail to identify the number of input and'output

channels, their frequency plan, interconnectivity. and redundancy

implementation to achieve the desired reliability. Estimates of

processor weight, power and volume were based on data from 30/20

GHz communications System Baseband Processor Subsystem, Phase I

Final Report (Ref. 45).

Interface to Bus. The primary purpose of these sections are to

collect and synthesize the interface requirements for the various

aggregated payload concepts into a consistent use of requirements

to be made available to a geosynchronous platform bus study and/

or potential bus manufacturer. The concept of a large, geosynchronous telecommunications facility preserves the classical

payload-to-bus interfaces (mechanical. electrical, thermal,

telemetry/command, and attitude control). The level of interface

documentation required is determined by the particular payloadto-bus integration scheme implemented. These schemes range from

the "palletized" payload concept, complete with antenna support

structure, requiring a simple bus interface and relatively little

interface information, to the more complex "component" payload

concept where individual elements require integration to the bus

and unit level interface information must be supplied. The type

of interface information required for each integration scheme is

listed in Table 5.1-6. From an overall program management

standpoint. palletized payloads appear to be more nearly

optimum. This concept establishes clear, well defined areas of

responsibility and performance, simplifies the integration and

test of the payload. and possibly simplifies in-orbit servicing

and replacement. The controls interface is influenced

significantly by the antenna system selected and the control of

large flexible structures.

5-12
Ford Aerospace &

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Table 5.1-6

Bus Interface Parameters

For Each Payload Scenario;

Service: (C. Ku. Ka. DBS. etc.)

Payload Description: (Type. Number, etc.)

Mass: (kg)

Power Required: (kW)

Eclipse Capability: (100%. 50%. 0%)

Pointing Requirement: (°)

Antenna Description: (Type. Size. Physical Constraint, and

Number)

Temperature Requirement (°C)

Lifetime: (years)

Boxes (Count and Dimensions)

5-13
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 Aerospace &

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5.2 SCENARIO II DEFINITION

5.2.1 Introduction

Scenario II can be described as a transition satellite

containing conventional, current, two times re-use C-band and

three times re-use Ku-band payloads. In addition, it provides a

high capacity Ka-band fixed and scanning beam payload and an

introductory level Ku-band DBS payload. The services provided

are listed below:

1) 24 channels, 36 MHz, standard C-band FSS payload. 2 x re-use

2) 24 channels, 54 MHz, standard Ku-band FSS payload, 3 x re-use

3) 20 beams. 38 channels, 500 MHz, Ka-band FSS trunking payload,

7.6 x re-use

4) 6 area scan beam, 18 channels - 240 MHz, and 14 channels -

500 MHz. Ka-band CPS/thin route trunking. 5.76 x re-use.

5) 16 channels, 24 MHz, Ku-band. DBS payload, 2 beams. 8

channels each.

The satellite is primarily intended as a Fixed Satellite

Service (FSS) satellite although it also contains a Direct

Broadcast Service (DBS) payload. This combination of payloads

puts severe limitations on its orbital positioning since

currently only 101 and

locations for all the payloads.

currently only 101 and 110 W longitude are compatible

An overview block diagram of the payload elements is shown in

Figure 5.2.1-1. Table 5.2.1-1 lists the major scenario bus

interface requirements and Tables 5.2.1-2 and 5.2.1-3 present the

major antenna and transponder characteristics respectively. The

two Ka-band antennae require individual gimbal systems for

o

steering the two sub-reflectors to achieve +0.02 pointing of

the RF boresight. The other antennae will be rigidly mounted to

the spacecraft body and body steered via the bus control system.

5-14
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5-15
Ford Aerospace &

Communications Corporation

Table 5.2.1-1

Scenario II - Pavload Summary

Mass 2065 kg

Power Required

Sunlight

Eclipse

13,000 watts

75% min.; 100% desired

Pointing Requirement +. 0.05 absolute (ie:RF

boresight)

Temperature Requirements

Antenna

Transponder

-90°C to 110°C

-10°C to + 50°C.

(TWTA's + 60°C)

Thermal Dissipation appx. 5 kW TWT's; 500 W

EPC's & 1 kW feeds

Lifetime 10 yr. without servicing

5-16
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Table 5.2.1-2

Scenario II Antenna Configuration

Antenna System Freq (GHz) Reflector Polarization Feed

o c-Band FSS 6/4 Dual Gridded

reflector

1.4x1.8m

Linear 2x7-feed

arrays

o Ku-Band FSS 14/11 Dual gridded

Reflector

8'(2.44m)

Linear 2x80-feed

Arrays

O KU-Band DBS 17/12 One solid 8'

(2.44m)reflector for Tx..one

solid 6'(1.8m)

reflector

for Rx.

CP 2x55-feed

Arrays

(requires

septum

polarizer)

o Ka-Band FSS 30/20 One solid 13'

(4m. )ref lecrtor for Tx one

solid 9'(2.7m)

reflector for

Rx.(dual shaped

reflector each

with sub-reflector)

Linear Tx:

500 feeds.

830 switches

140 OMJ's;

same for Rx.

5-17
Ford Aerospace &

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Table 5.2.1-3

Transponder Summary Scenario II

U/L.D/L

Payload Freq.GHz

C-Band

FSS 6/4

Number Channel RCVR Type. HPA Type HPA

Channels^ BW (MHz.) (Number) (Number) Power.W

24 36 6/4(4) SSPA(30) 8.5

Ku-Band 14/11

FSS

24 54 14/11(6) TWTA(30) 50

Ku-Band

DBS 17/12 16 24 17/12(4) TWTA(20) 100

Ka-Band

FSS 30/20 38 500 30/4(40) TWTA(49) 75

Ka-Band

Scan 30/20 32 240/500 30/4(12) TWTA(40) 75

Due to the use of TWTA's for the Ku-band FSS and DBS payloads. a

10 year life is all that can be envisioned at this time. The

replacement of TWTA's at GEO. or return of the payload from GEO

for servicing and replacement of TWTA's. is not anticipated for

the early year 2000 time period. It is estimated that the

identified redundancy is compatible with a 10 year life

application.

If lower risk technology is utilized it is possible that fuel

servicing at GEO or perigee augmentation at LEO could be utilized

to maintain the Launch Concept 1 status of the payload.

Table 5.2.1-4 presents a summary of the high and low risk weight

and power for the individual payload elements in Scenario II.

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Table 5.2.1-4

Scenario" II - Weight and Power

C-Band FSS

transponder

Antenna

Sub Total

WEIGHT(KG) POWER(W)

Low Risk High Risk Low Risk High Risk

102.3

19.1

121.4

72.2

16.7

88.9

922

922

659

659

Ku-Band FSS

Transponder

Antenna

Sub Total

280.5

34.1

314.6

231.7

28.8

260.5

3444

3444

2522

2522

Ku-Band DBS

Transponder

Antenna

Sub-Total

246.3

31.5

277.8

195.5

27

222.5

4554

4554

3876

3876

Ka-Band FSS & Scan

FSS Transponder

SCAN Transponder

Baseband Proc.

Antenna

Sub-Total

751.4

636.0

355.0

264.5

516.3

447.6

297.4

230.4

3305

2180

1360

4

3043

1936

952

2

2006.9 1491.7 6849 5933

SCENARIO II TOTAL 2720.7 2063.6 15769 12990

5-19
Ford Aerospace &

Communications Corporation

In Appendix G-4. Tables 1 thru 14. show that all of the payload

elements have viable links with the various types of anticipated

modulation and access types. While some of the margins are low.

the links represent the worst case conditions, and if this

scenario were to be studied further for full system definition,

link margins could be improved for actual implementation. A

typical link for the C-band FSS Companded Single Side Band

carrying 6000 half-voice circuits is shown in Table 5.2.1-5.

5.2.2 C-Band FSS Payload

5.2.2.1 Overview of C-Band FSS

This payload is patterned after current day C-band. 24 channel

payloads used by ATT. RCA. Galaxy, etc. This would be a

replacement for continuation of service. It provides a 2 times

re-use factor via horizontal and vertical, linear polarization

isolation. The coverage is full CONUS with some selected

coverage for Alaska, Hawaii and Puerto Rico. The payload

features dual-gridded reflectors to obtain the polarization

purity required. The reflectors are a stacked assembly with

slightly offset focal points for physical separation of the feed

assemblies. The transponder is a straight forward design and no

on-board processing is provided. Figure 5.2.2-1 is a block

diagram of the C-band FSS payload for Scenario II showing the

breakdown to the component level.

Table 5.2.2-1 shows the estimated weight, power, and volume for

low risk (emerging) technology and high risk (projected)

technology for the transponder and antenna. Also included in the

estimates are the coax, waveguide, and harness interconnects,

plus an estimate for integration hardware to put the components

together and provide necessary brackets for support and

mounting. This does not. include any structure or satellite

mounting hardware such as between the feed and reflector.

5-20
Ford Aerospace &

Communications Corporation

Table 5.2.1-5

Scenario II - C-Band (FSS) - Link Budget

MODULATION: CSSB, Suppressed Carrier (6000 HVC/36 MHz)

Mid-band Downlink Freq. =

Mid-band Uplink Freq. =

Uplink Free Space Loss =

No. of Channels, N =

Transmitter Power

Transmit Line Loss

Transmitting Antenna Gain

Output Backoff

Net EIRP

Total Load

' Reference Power EIRP, Pr

Free Space Loss

Pointing Loss

Atmospheric Degradation

Net Path Loss

Power Flux Density

Receiving Antenna Gain

Receive Line Loss

System Noise Temperature

Receive G/T.

Boltznann's Constant

Downlink Pr/No

Uplink Pr/No

Downlink Interference Pr/Io

Uplink Interference Pr/Io

Intermodule tion Pr/IMo

Terrestrial Pr/Io

Cross-polarization Pr/Io

Overall Pr/No

Required Pr/No

Pr/No Margin

3.95 GHz

6.15 GHz

200.0 dB

6000

10.0 dBW

1.3 dB

25.0 dBi

5.0 dB

28.7 dBW

22.6 dBmO

67? dBW

196.1 dB

0.5 dB

0.0 dB

196.6 dB

-134.0 dBW/m2

50.1 dBi

0.1 dB

19-4 dB-K

3077 dB/K

-228.6 dBW/Hz-K

6878 dB-Hz

71.6 dB-Hz

68.8 dB-Hz

68.9 dB-Hz

68.9 dB-Hz

86.7 dB-Hz

79.6 dB-Hz

6771 dB-Hz

61 .9 dB-Hz

0.3 dB-Hz

Saturated EIRP =36.0

SFD =-84.0

Satellite Gain =161.1

Satellite G/T = -2.1

10.00 Watts

Allocation

Gridded Reflector

-15.2 + 10 Log N

Net EIRP - Total Load

38700 km; 30° Elev

Allocation

(Clear'^Sky)

10 m dish, 605? eff .

Allocation

(Clear Sky)

Worst-case

14.7 dB = P1/P3

dBW

dBW/'ni

dB

dB/K

5-21
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5-22
ORIGINAL PAGE IS

Of POOR QUALfTY

Table 5.2.2-1

!

Scenario II - Pavload Summary

C-Band FSS

ORIGINAL PAGE IS

OF POOR QUALFTY

ITEM

1

2

3

A

c

£

7

8

9

10

1

2

q

14

IS

16

17

1R

19

20

21

22

23

24

25

26

27

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29

in

• •

C~BAND RECEIVER . 6/ 4 GHz

INPUT MULTIPLEXER, 6 CHANNEL, 36 MHz

REDUNDANCY SWITCH MATRIX (RING) 5/4 |

Comm Contro l .& Interfac e

SSPA, 4 GHz, 8.5 WATT with 2 VGA' s

REDUNDANCY SWITCH MATRIX (RING) 5/4

OUTPUT MULTIPLEXER 6 CHANNEL

HARMONIC FILTER

PRESELECT FILTER WITH ISOLATOR !

SPOT SWITCHES COAX

TRANSFER SWITCH. COAX !

3 dB HYBRID !

COAX. SET

WAVEGUIDE. SET

HARNESS i

INTERATION HARDWARE. SET

M a r g_i n R e q ' d !

Tota l Trasnoonde r i

Antenn a Refl ector (Dua l Gridded )

Antenn a Feed Vertica l

Antenn a Feed Horizonta l 1

f'argi n Req' d j

I ota I Antenn a

TOTAL PAYLOAD

P/L

QTY

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6

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160

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7200

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25

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20

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cFOUXXJT 5-23

Ford Aerospace &

Communications Corporation

FOtDOUT FRAME
Ford Aerospace &

Communications Corporation

5.2.2.2 Antenna

The C-Band FSS antenna subsystem provides transmission at 4 GHz

and reception at 6 GHz of dually linear-polarized communications

signals. The antenna coverage regions include CONUS. Alaska.

Hawaii, and Puerto Rico as depicted in Figure 5.2.2-2. The

odd/even mode of operation is employed in the transmit system to

alleviate the difficulty in the design of a multiplexer. Table

5.2.2-2 presents the antenna subsystem requirements.

Table 5.2.2-2

C-Band FSS Antenna Subsystem Requirements

Parameters Requirements

Frequency Transmit: 4 GHz band

Receive: 6 GHz band

Polarization Dual Linear

Coverage Area Combination of CONUS, Alaska, Hawaii,

and Puerto Rico

Co-Polarization None

Isolation

Cross-Polarization 30 dB

Isolation

The antenna will consist of two gridded, offset-fed reflectors

and two multi-horn feed array systems, one for vertical and

another for horizontal polarization. as depicted in Figure

5.2.2-3. Each reflector/array system operates in both the

transmit and receive bands. The block diagram of the

5-24
Ol mu0)>ouOJ ccCOen(0COICMICM0)u3

o

5-25
Ford Aerospace &

Communications Corporation

Figure 5.2.2-3 Geometry for C-Band Reflector

with 12-inch Offset

i

PARABOLIC PROFILE' .

*ili >£-

4f Z04

SECTION OF

PARABOLIC

SURFACE

ri.OOin

5-26
Ford Aerospace &

Communications Corporation

communications antenna subsystems are shown in Figures 5.2.2-4

and 5.2.2-5. The gridded reflector is used to lower the

reflected cross-polarized energy generated by the offset

reflector surface and the feed array. Such a system can provide

at least 30 dB cross-polarization isolation.

The predicted antenna radiation patterns are shown from Figures

5.2.2-6 to 5.2.2-12. The calculated edge-of-coverage gains are

summarized in Table 5.2.2.3

Table 5.2.2-3

C-Band FSS Predicted Performance

Predicted

Polarization Function Coverage Region Gain (dB)

Estimated

Percent of

Required

Area covered

by Predicted

Gain (%)

Transmit

Vertical Transmit

Transmit

Receive

Transmit

Transmit

Transmit

Horizontal Transmit

Transmit

Receive

CONUS

Alaska

CONUS+Alaska

CONUS+Alaska

CONUS

Hawa i i

Puerto Rico

CONUS +Hawaii

CONUS+Puerto Rico

CONUS + Hawaii

+ Puerto Rico

27.0

26.8

26.5

27.0

25.0

25.0

27.2

31.8

29.7

25.1

25.1

25.1

99.5

99.9

100.0

100

100

100

100

100

100

100

100

100

5-27
Ford Aerospace &

Communications Corporation

Figure 5.2.2-4 Horizontal Transmit Polarization Feed System

REFLECTOR

PN

r r

Y Y

T_

0 HAWAII

PD

PN

*• L

Y Y

0/E PD

6

I

6

0

CONUS

E PUERTO RICO

TRANSMIT

PN

PN

PD PN

rO

RECEIVE

PO

PO PN

H - HAWAII

P - PUERTO RICO

5-28
Ford Aerospace &

Communications Corporation

Figure 5.2.2-5

Vertical-Transmit Polarization Feed System

PN

PD

I I I I

PN

n

0/E PD

I I D

ALASKA CONUS

TRANSMIT

PN

PN PO

RECEIVE

PN PD PN

A • ALASKA

C - CONUS

D - DIPLEXER

PD • POWER DIVIDER

0/E PD - ODD/EVEN POWER DIVIDER

PN - PHASING NETWORK

E - EVEN

0 .000

5-29
Ford Aerospace &

Communications Corporation

OF POOR

Figure 5.2.2-6 Calculated Transmit Innermost Vertical

Polarization Contour - CONUS and Alaska

•ZBdBI

MINIMUM QAIN • 27.0 MINIMUM GAIN

- 27 d8i. 99.8% COVERAGE

- 20.8 dBI. 99.9% COVERAGE

- 26.6 OBi. 100% COVERAGE

SPECIFIED COVERAGE REGION

COVERAGE REGION INCLUDING

S/C POINTING ERRORS

Figure 5.2.2-7 Calculated Innermost Transmit Vertical

Polarization Contour - CONUS and Alaska Combined

MINIMUM GAIN - 25.0 dB

SPECIFIED COVERAGE REGION

COVERAGE REGION INCLUDING

S/C POINTING ERRORS

CONUS

5-30
Ford Aerospace &

Communications Corporation

Figure 5.2.2-8 Calculated Innermost Receive Vertical

Polarization Contours

MINIMUM GAIN - 26.4 dBi

SPECIFIED COVERAGE REGION

COVERAGE REGION INCLUDING

SIC POINTING ERRORS

Figure 5.2.2-9 Calculated Innermost Transmit Horizontal

Polarization Contours - CONUS and Puerto Rico

SPECIFIED COVERAGE REGION

COVERAGE REGION INCLUDING

sic POINTING ERRORS

\ DIRECTIVITY

\ \ 29 dBi

In

/ / MINIMUM GAIN

/ • 27.2 dBi

DIRECTIVITY

33dBi

32dBi

MINIMUM GAIN • 31.8 dBi

DIRECTIVITY

31d8i

30 dB

MINIMUM GAIN • 29.7 dBi

5-31
Ford Aerospace &

Communications Corporation

Figure 5.2.2-10 Calculated Innermost Transmit Horizontal

Polarization Contours - CONUS and Puerto Rico

SPECIFIED COVERAGE REGION

COVERAGE REGION INCLUDING

S/C POINTING ERRORS

MINIMUM GAIN • 25J dSi

Figure 5.2.2-11 Calculated Innermost Transmit Horizontal

Polarization Contours - CONUS and Hawaii

SPECIFIED COVERAGE REGION

COVERAGE REGION INCLUDING

S/C POINTING ERRORS

DIRECTIVITY

27 dBi

26dBi

MINIMUM GAIN • 26.1 OBI

5-3 2
Figure

ontal

D»RECTIVITY

SPECIFIED COVERAGE REGION

COVERAGE REGION INCLUDING

S?C POINTING ERRORS

CONUS

M.N.MUMGA.N-25.K8-.

5-33
Ford Aerospace &

Communications Corporation

The critical technology items of an antenna subsystem are

isolation, pointing accuracy, variable power divider (VPD) /

Phase shifter (VPS), feed array, and reflector. No technology

development is required in the C-band FSS antenna subsystem

except the reflector. The weight of the reflector could be

reduced about 20% in 1994 due to the more advanced materials that

are being developed for the reflector surface. The assessment of

these critical items are presented in Table 5.2.2-4.

Table 5.2.2-4

Assessment of Critical Technology Items

ITEM LOW RISK HIGH RISK

Isolation Co-pol NA NA

Isolation Cross-pol 30 dB 33 dB

Pointing Accuracy None None

Reflector Weight:llkg Weight: 9kg

Feed Array Weight:?.2 kg

Graphite Epoxy

Weight: 6.0 kg

VPD/VPS NA NA

5.2.2.3 C-Band Transponder. Fixed Satellite Service

The C-Band transponder subsystem consists of two independent.

12 channel transponders, and hence provides a total channel

capacity of 24 channels, each of 36 MHz bandwidth. Both

transponders utilize the same 500 MHz FSS band, having an uplink

5-34 •
Ford Aerospace &

Communications Corporation

at 6 GHz and a downlink at 4 GHz. The transponders receive their

inputs from the verticallypolarized (Alaska/CONUS coverage) and

horizontally polarized (Hawaii/Pureto Rico/CONUS coverage) antenna

feed assemblies. Each of the two 6 GHz inputs is filtered by an

input preselector and then amplified and downconverted to 4GHz by

the receiver. The 500 MHz IF band is subdivided by an input

multiplexer into twelve. 36 . MHz channels. The channels are

individually amplified by SSPAs which contain one or more variable

gain amplifiers. The latter permit automatic accommodation of

varying uplink levels, using an AGC loop, and SSPA back off via

ground control. The signals in the two sets of twelve individual

channels are combined in two twelve channel output multiplexers and

filtered by harmonic/band pass filters prior to transmission from

the vertically and horizontally polarized transmit antennas. The

transponder subsystem features four for two receiver redundancy and

five for four SSPA redundancy. Component descriptions for low risk

and high risk technology are contained in the following sections.

5.2.2.3.1 6/4 GHz Receiver

Using low risk technology this receiver provides for low noise

amplification at 6 GHz. It down converts 6 GHz to 4 GHz with a

Schottky diode mixer. The mixer is followed by bandpass

filtering and amplification at 4 GHz. The local oscillator is a

temperature controlled crystal oscillator followed by a

multiplier chain.

Electrical Performance

Noise Figure 3.0 dB

Gain 70 dB

Output Power @c/3IM=-40dBc +13 dBm

Freguency stability +1/-2 ppm

DC power 7.5 watts

5-35
Ford Aerospace &

Communications Corporation

Mechanically, the receiver contains four subasserably trays a

front end. a driver, a local oscillator and a DC/DC converter.

The trays are assembled in a vertical stack. RF signal

connections between the front end. driver and local oscillator

trays are made with short loops of semirigid coaxial cable. A

selectable coaxial attenuator is included in the RF signal path

at the input to the driver to allow for adjustment of the overall

gain. Regulated DC voltages are supplied to the front end.

driver and local oscillator trays through a DC harness running

vertically along the side of the stack.

The microwave tray is an aluminum chassis that contains

substrate assemblies that are bonded into the chassis, and

substrate/carrier assemblies that are bolted in the chassis. The

substrate assemblies consist of MIC isolators. filters and

temperature compensation. The substrate/carrier assemblies are

MIC amplifiers. These amplifiers are constructed using

hermetically packaged semiconductors, chip resistors, and chip

capacitors on thin film alumina substrates. The bias circuits

are constructed using thick film alumina substrates, hermetically

packaged semiconductors, chip resistors and chip capacitors.

Mechanical Parameters

Mass 1.6 kg

Volume 175 cu in.

Using high risk technology, the 6 GHz preamp will be updated

with the latest low noise GaAs FET. This will improve noise

figure from 3.0 dB to 1.5 dB. The mixer should be integrated

with the bandpass filtering. The will enhance the mixer

performance by improving gain flatness over temperature and

reducing test time. The 4 GHz amplifiers should be replaced by

monolithic gain blocks. These gain blocks are common to this

receiver and many other applications. This would reduce test

5-36
Ford Aerospace &

Communications Corporation

time and improve overall receiver performance. The crystal

oscilator chain could be replaced by a dielectric resonator

oscilator. The DRO will reduce complexity and cost. The current

receiver uses an analog circuit to temperature compensate the

receiver gain. Future receivers should use a digital system to

improve gain stability. The preamp. mixer/filter. DRO. and

digital temperature compensation require development that is

geared toward space qualification. The 4GHz gain block would be

developed in the commer-ical market and could be space qualified.

Power consumption will be reduced 4.8 watts primarily by the use

of the DRO.

The use of monolithic gain blocks and dielectric oscilators

will reduce the size of the receiver. The number of

subassemblies can be reduced from 4 to 3. These would be a DC/DC

converter, front end/local oscilator. and driver.

Mechanical Parameters

Mass 0.7 kg

Volume 50 cu in.

5.2.2.3.2. 4 GHz Input Multiplexers

Using low risk technology, dual mode TE113 dielectric quasi

elliptic filters and equalizers will be used. The electrical and

mechanical design for the 24 and 36 MHz channels will be similar

to that qualified and flown on the Arabsat program. Circulator

coupling and hybrid splitting of adjacent channels will be used

as is standard on today's communications satellites. Depending

on the specifications, self-equalized filters may be required.

The dielectric resonators will be housed in aluminum cylindrical

cavities with two orthogonal modes used per resonator to minimize

size and weight.

5-37
Ford Aerospace &

Communications Corporation

The 240 and 500 MHz wide channels would be realized in moreconventional standard rectangular or possibly

 TEii dual mode

cylindrical cavities. Depending on the specifications, these

cavities could be aluminum. Again depending on the specifications, a coaxial resonator filter made of aluminum may well

meet the requirements. A 14 section coaxial cavity coupled

filter is used as the 241 MHz input channel filter on the

Intelsat V program. This approach is light weight and very

compact.

Using high risk technology, dielectric resonators currently

exist for realizing the 24 and 36 MHz wide 4 GHz input filters as

explained above. however, much work remains to be done in

providing lighter weight packaging. There are several promising

approaches that need investigation to determine if low electrical

losses can still be achieved with very small packages. These

approaches would involve integrated construction with isolators

and filter resonators in the same plane to permit stacking and

easy interfacing with MIC and monolithic amplifiers. Amplifier

coupling could be used at the input of each filter to minimize

the need for isolator coupling. Chip amplifiers would certainly

weigh less than a ferrite circulator.

In addition, it is anticipated that low loss temperature-stable

resonator materials with dielectric constants of 80 will be

available in the next few years. Currently, available materials

are approximately in the 30 range. The higher dielectric

constant will permit the realization of smaller and more compact

filter packages both at 4 and 11 GHz.

These packages could easily be integrated with monolithic

amplifiers and mixers to achieve high performance and very

compact receivers. Unique construction techniques and filter

types need to be developed to take advantage of these emerging

technologies in microwave monolithic circuits and materials.

5-38
Ford Aerospace &

Communications Corporation

No significant improvement in the coaxial cavity filters is

anticipated by 1994. if the specifications permit the use of

these filters. Since they are coaxial their loss and insertion

loss variation are higher than waveguide filters. Hence, they

are not suitable for all input multiplexer application.

5.2.2.3.3 4 GHz SSPA. 8.5 Watt

Using low risk technology the 8.5 watt/ 4 GHz solid state power

amplifier would use Gallium Arsenide FETs as the active devices.

The output stage combines the output of three 3-watt FETs and is

driven by one 3 watt FET of the same type. This 3 Watt device

has matching circuits incorporated within the device package to

match the FET chip to 50 ohms, thereby minimizing amplifier tune

and test time and maximizing the performance by accomplishing the

matching as closely as possible to the chip. The three-way

divider/combiner circuit uses a 4.77 dB interdigitated (Lange)

coupler and a 3 dB interdigitated coupler. Four stages of low

power gain precede the power stages. Two of these low level

stages use dual-gate FETs to provide a variable gain which is set

by the voltage on the second gate. The RF circuitry is etched in

thin film metalization on alumina substrates which are bonded to

moly or Kovar carriers. The amplifier uses a modular construction. Four separate modules are individually tuned and

tested and then integrated. Four interstage isolators are

included to minimize interaction between the modules when they

are integrated. The isolators are the drop-in microstrip type to

minimize size and weight, except for the output isolator which is

stripline for lowest loss.

Using high risk technology, rapid advances in gallium arsenide

technology and monolithic microwave integrated circuits (MMICs)

should make possible substantial improvements in size and

performance by 1994. Because of thermal considerations and the

need to maximize the efficiency, it is not expected that the

output stage will be in monolithic form. It is anticipated.

5-39
Ford Aerospace &

Communications Corporation

however, that 8.5 watts output power will be available from a

single device package with probably two FET chips, and with

matching circuitry and combining circuitry integrated within the

single package. This will reduce the size by eliminating the

need for the large three-way divider/combiners. MMIC technology

should make it possible to integrate several stages of low poweramplification on a single chip. Similarly the VGA should be

realizable on a single chip. Thus, a 1994 8.5 watt amplifier

could consist of two -low power gain chips, a driver amplifier in

one device package, and the output stage in a second package,

leading to a significant reduction in size and weight.

5.2.2.3.4 4 GHz Output Multiplexers

Using low risk technology. the up to 12 channel 4 GHz

multiplexers would be built using the graphite epoxy (GFRP)

technology developed for the multiplexers on the Intelsat V

program. The GFRP material is light weight, strong, and as

temperature stable as the much heavier steel alloy, invar. Dual

mode cylindrical cavities would be used in order to reduce the

number of required cavities for an n pole filter to n/2. A

common GFRP waveguide would be used to combine the outputs of the

filters to form the multiplexers. This design approach has been

qualified and flown on the Intelsat-V. Insat and Arabsat programs.

Properties of dielectric materials for microwave applications

are constantly improving. Using high risk technology. the

electrical loses at 4 GHz will be equivalent to. or better than,

waveguide filters. Dielectric resonator filters have been used

for input filters on the Arabsat program and by 1994 will be used

in 4 GHz output filters at power levels up to 10 watts. These

filters will use dual mode dielectric resonators to reduce the

number of cavities. The cavity walls will be made of aluminum to

save weight, and their outputs will be combined on a common

waveguide or coaxial manifold depending on the system interface

requirements.

5-40
Ford Aerospace &

Communications Corporation

There is important work that should be done on the physical

mounting of the resonators so that they are rugged enough to

survive launch without degrading the electrical performance. In

addition, methods of keeping the resonators cool under high power

conditions must be studied. The work should result in a mass and

size 3 times smaller than available today.

5.2.2.3.5 Preselect and Harmonic Filters

Using low risk technology. standard Tchebyscheff

 TR

O1

rectangular aluminum waveguide filters are used for preselect

filters. This technology has been used for decades and the

design approach and implementation are routine. Standard waffle

iron filters have been used for decades as harmonic filters.

Recently. new advanced designs have been developed that are

smaller and lighter. These designs have been qualified and flown

on the Intelsat V program. These new designs have successfully

passed multipaction testing at power levels of 1000 watts.

Since there is generally only one preselect or harmonic filter

per antenna feed, efforts to significantly reduce the size and

weight have very little impact on satellite mass and layout.

Preselect filters and harmonic filters are usually implemented in

aluminum waveguide and so do not weigh much more and are no

larger than a short piece of waveguide.

In addition, these filters are often installed as a part of the

waveguide run from the antenna feeds to the input or output of

the transponder and so take up no additional space. Therefore,

no improvement in preselect or harmonic filter technology is

anticipated or required for future applications.

5-41
Ford Aerospace & • i/ •••'•y&Q

Communications Corporation ' . ,,.

.' ;. '.;'.KS-:- ^'

5.2.3 Ka-Band FSS Payload

5.2.3.1 Overview of a Ka-Band FSS Payload

The payload is to handle the 20 largest traffic center trunking

nodes between themselves and via interconnect to the second tier

switch and the baseload processor to the rest of CONUS traffic.

The selected 20 nodes were based on the Western Union Study, as

discussed in Section 4. The twenty beam locations were converted

to latitude and longitude in Appendix G-l.l for antenna design

purposes. The system was allowed to use the entire 2.5 GHz of

bandwidth; however, as can be seen in the block diagram. Figure

5.2.3-1. only two locations required the entire bandwidth and

many required less than 20% of the bandwidth for equivalent

percentage of actual traffic applied based on the CONUS distribution model. The payload uses all digital traffic at very high

data rates, 960 Mb/s. and very high speed on-board SS-TDMA. The

system uses an 8 PSK modulation to achieve a 2 bit per Hertz,

highly efficient modulation scheme. The antenna system requires

two reflectors and two sub-reflectors, with the sub-reflectors

gimbalied for independent pointing control of the 0.3°

beamwidth beams for receive and transmit.

Table 5.2.3-1 shows the estimated weight, power and volume for

low risk (emerging) technology and high risk (projected)

technology for the transponder and antenna. Also included in the

estimates are the coax, waveguide, and harness interconnects,

plus an estimate for integration hardware to put the components

together and provide necessary brackets for support and

mounting. This does not include any structure or satellite

mounting hardware rack between the feed and reflector.

5.2.3.2 Ka-Band FSS Antenna Subsystem

The Ka-band FSS antenna subsystem provides transmission at 20

GHz and reception at 30 GHz of dually linear-polarized

5-42
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ORIGINAL PAGE IS

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communication .sig.nals.- .>The antenna will produce 20 simultaneous '»•: r- : • '•«.'.'.?!>•

fixed beams' '.directed:^'a;t: twenty specified cities in CONUS. as

shown in Figure 5.2.3-2. The interbeam isolation shall be 30 dB

or better. Table 5.2.3-2 summarizes the antenna subsystem

requirements..

Table 5.2.3-2

Ka-Band FSS Antenna Subsystem Requirements

Parameters Requirements

Frequency Downlink 17.7-20.2 GHZ

Number of Beams 20

Polarization Dual Linear

C/l 30 dB

Pointing Accuracy Pitch & Roll

Yaw

0.02

0.4 '

The antenna will consist of two dual offset shaped reflectors,

one 4 meter for downlink and one 3 meter for uplink, as depicted

in Figure 5.2.3-3 and 5.2.3-4. The reflector surface is shaped

to produce a 0.3 half-power beamwidth with less than 1 dB scan

loss over the view of CONUS. A seven (or up to thirteen) element

cluster of waveguide horns will be used to produce a low sidelobe

radiation pattern for each beam. Figure 5.2.3-5 shows a typical

fixed beam antenna pattern. The cross polarization is below 40

dB and therefore is not included. The predicted antenna performance is summarized in Table 5.2.3-3.

5-45
ORIGINAL PAGE IS

OF POOR QUALITY

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5-46
Ford Aerospace &

Communications Corporation ORIGINAL PAGE IS

OF POOR QUALITY

Figure 5.2.3-3 Downlink MBA

Configuration

Figure 5.2.3-4 Uplink MBA

Configuration

5-47
Ford Aerospace &

Communications' Corporation.

ORIGINAL PAGE IS

OF POOR DUALITY

Figure 5.2.3-5 Measured El Pattern Horizontal Polarization

NASA 30/20 GHz MBA

AMCU

S-48
Ford Aerospace &

Communications Corporation

Table 5.2.3-3

\

Predicted Ka-Band FSS Antenna Subsystem Performance

Peak Gain 53 dBi

Sidelobe Isolation 30 dB

Cross-Pol Isolation 30 dB

The same antenna may be used for the Ka-band scan antenna

subsystem. The critical technology items will be addressed in

that subsection.

5.2.3.3 Ka-Band Transponder. Fixed Satellite Service

The Ka-Band FSS Transponder Subsystem consists of two 5 channel

transponders, one 3 channel transponder, eight 2 channel transponders, and 9 single channel transponders, each channel having a

500 MHz bandwidth. Channel switching between beams and cross

links to the scan beams are accomplished at the 4 GHz intermediate frequency.

The twenty outputs of the receiver beam forming network are fed

to dedicated receivers via preselector filters. The receivers

amplify and downconvert the received signals to the 4 GHz IF

band. The IF bands of all but the single channels transponder

are subdivided in two. three or five channels by the input

multiplexers, which also provide the required narrow band receive

filtering responses. The input multiplexers are followed by five

switch matrices which allow connections between a) the two Fl

channels, b) the six F2 channels, c) the five F3 channels, d) the

five F4 channels, and e) the twenty F5 channels. In addition,

the F3. F4 and F5 switch matrices (7x7. 7x7 and 2x22, respectively) have two extra input and output ports to permit

interconnection between the Ka-Band, FSS transponders and the

Ka-Band. scan beam transponders. The 38 FSS outputs of the

switch matrices are amplified in variable gain amplifiers, then

5-49
Ford Aerospace &

Communications Corporation

upconverted to 20 GHz. The upconverter output amplifier has the

capability of driving the highest power TWTA (TWTA RF output

ranges from 5 watts to 75 watts) to saturation.

The outputs of the TWTAs in the single channel transponders are

narrow band filtered, and the outputs of the remaining TWTAs are

recombined in output multiplexers. which also provide the

required narrow band transmit filtering response. The downlink

signals are further filtered by passband and harmonic filters

prior to transmission from the beam forming network and offset

fed Cassegrain transmit antenna.

The transponder subsystem features four for two redundancy for

the receivers, and five for four redundancy for the 38 upconverters and TWTAs. Component descriptions for low risk and high

risk technology are contained in the following sections.

5.2.3.3.1 30/4 GHz Receiver

Using low risk technology, this receiver provides for a low

noise mixer that down converts 30 GHz to 4 GHz with a Schottky

diode mixer. The mixer is followed by bandpass filtering and

amplification at 4 GHz. The local oscillator is a temperature

controlled crystal oscillator followed by a multiplier chain.

Electrical Performance

Noise Figure 8.5 dB

Gain 70 dB

Output power @ C/3IM = 40dBc +13 dBm

Frequency stability + 1/-2 ppm

DC power 8.0 watts

Mechanically the receiver contains four subassembly trays: a

front end, a driver, a local oscillator and a DC/DC converter.

5-50
Ford Aerospace &

Communications Corporation

The trays are assembled in a vertical stack. RF signal

connections between the front end. driver, and local oscillator

trays are made with short loops of semirigid coaxial cable. A

selectable coaxial attenuator is included in the RF signal path

at the input to the driver to allow for adjustment of the overall

gain. Regulated DC voltages are supplied to the front end.

driver, and local oscillator trays through a DC harness running

vertically along the side of the stack.

The microwave tray is an aluminum chassis that contains

substrate assemblies that are bonded into the chassis and

substrate/carrier assemblies that are bolted in the chassis. The

substrate assemblies consist of MIC isolators, filters and

temperature compensation. The substrate/carrier assemblies are

MIC amplifiers. The amplifiers are constructed using

hermetically packaged semiconductors, chip resistors, and chip

capacitors on thin film alumina substrates. The bias circuits

are constructed using thick film alumina substrates, hermetically

packaged semiconductors, chip resistors and chip capacitors.

Mechanical Parameters

Mass 1.6 kg

Volume 175 cu in

Using high risk technology, the 30 GHz/4 GHz receiver will be

proceeded by a low noise GaAs FET amplifier. This will improve

the noise figure from 8.5 dB to 4.0 dB. The mixer should be

integrated with the bandpass filtering. This will enhance the

mixer performance by improving gain flatness over temperature and

reducing test time. The 4 GHz amplifier should be replaced by

monolithic gain blocks. These gain blocks are common to this

receiver and many other applications. This would reduce test

time and improve overall receiver performance. The crystal

oscillator chain could be replaced by a dielectric resonator

5-51
Ford Aerospace &

Communications Corporation

oscillator. The DRO will reduce complexity and cost. The

current receiver uses an analog circuit to temperature compensate

the receiver gain. Future receivers should use a digital system

to improve gain stability. The preamp. mixer/filter. DRO and

digital temperature compensation require development that is

geared toward space qualification. The 4 GHz gain block would be

developed in the commercial market and could be space qualified.

Power consumption will be reduced 5.5 watts, primarily by the use

of the DRO.

The use of monolithic gain blocks and dielectric oscillators

will reduce the size of the receiver. The number of subassemblies can be reduced from 4 to 3. These would be a DC/DC

converter, front end/local oscilator. and driver.

Mechanical Parameters

Mass 0.6K kg

Volume 50 cu in

5.2.3.3.2 4 GHz Input Multiplexer

See 5.2.2.3.2.

5.2.3.3.3 Dynamic IF Switch Matrix

Using emerging technology, the switch matrix provides 2.5 GHz

band width in the frequency band from 3.5 GHz to 6.0 GHz with a

switching speed of less than 5 ns. The basic architecture

contains a coupler cross-bar switch matrix.

This architecture has the following advantages:

o Planar structure with possible monolithic MIC in the

future,

o Modular approach with simple manufacturing.

5-52
Ford Aerospace &

Communications Corporation

o Enhanced reliability due to:

--Minimum active devices per crosspoint.

—Failure of a device results in. at the most.

the loss of only one crosspoint.

—Redundancy is simpler to implement.

o Good input/output match.

The switch amplifier module is a two-stage amplifier using dual

gate FET's in chip form. Matching circuits are implemented using

thin film MIC technology. Because of its modular form, any size

matrix from 2 x 2 to 22 x 22 can be constructed with the same basic

building blocks.

Electrical Parameters

Size 20 x 20

Switching Speed 5 ns

I.F.Frequency 3.5 to 6.0 GHz

Loss 20 dB

Gain Flatness 1.0 dB/GHz

DC Power 48 watts

The major emphasis in the mechanical package design is to

minimize size, reduce assembly time, and ease tuning and

testing. The package consists of two chassis mounted one on top

of the other. The chassis contain two submatrices: a 22 x 12

and a 22 x 10, which form the final 20 x 20 basic matrix, plus

two additional input rows, and two output columns needed for

redundancy (final size 22 x 22).

Each set of two crosspoints within the matrix consists of a

thin-film switch amplifier module and a thick film switch-driver

module. The input couplers and the switch-driver module are

5-53
Ford Aerospace &

Communications Corporation

installed on one side of the chassis. The switch-amplifier

modules and the output coupler substrates are installed on the

opposite side.

Mechanical Parameters

Volume 675 cu in

Mass 10 kg

Using high risk technology, the dynamic microwave switch matrix

design must be based on an extension of existing technologies.

The dual gate GaAs FET is the primary candidate for a switch at

frequencies higher than 1 GHz and at rates faster than 1 ns. The

gallium arsenide monolithic circuit technology in use today in

gigabit logic, monolithic microwave amplifiers, and monolithic

microwave mixers will be the basis for designing a microwave

switch matrix. An ideal building block would be a 10 x 10 port,

monolithic GaAs 1C. This 10 x 10 GaAs 1C would be the basic

building block for switch matrices of larger or smaller sizes.

Electrical Parameters

Size 20 x 20

Switching Speed 5 ns

I.F. Frequency 2 GHz to 20 GHz

Bandwidth 1 GHz

Loss 0 dB

Gain Flatness 1.0 dB

DC Power 32 watts

The major factor in determining the mechanical design is the

location and type of RF connectors and interconnection between

the 10 x 10 monolithic GaAs 1C. The 1C would be about 0.3 x 0.3

inches.

Mechanical Parameters

Volume 225 cu in

Mass 4 kg

5-54
Ford Aerospace &

Communications Corporation

5.2.3.3.4 4/20 GHz Upconvertor

Using low risk technology. the upconverter provides for

amplification at 4 GHz. It up converts 4 GHz to 20 GHz with a

Schottky diode mixer. The mixer is followed by bandpass

filtering. The local oscillator is a temperature controlled

crystal oscillator followed by a multiplier chain. The 4 GHz

amplification is done with dual gate FET's that also provide

variable or stepped gain control.

Electrical Performance

Gain 15 dB

Output Power @ c/3IM = -40dBc -10 dBm

Freguency stability +1/-2 ppm

DC Power 6.5 watts

Mechanically the upconverter contains three subassembly trays:

a front end. a local oscillator and a DC/DC converter.

The trays are assembled in a vertical stack. RF signal

connections between the front end and local oscillator trays are

made with a short loop of coax cable. Regulated DC voltages are

supplied to the front end and local oscillator trays through a DC

harness run vertically along the side of the stack.

The microwave tray is an aluminum chassis that contains

substrate assemblies that are bonded into the chassis, and

substrate/carrier assemblies that are bolted in the chassis. The

substrate assemblies consist of MIC isolators, filters and

temperature compensation. The substrate/carrier assemblies are

MIC amplifiers. These amplifiers are constructed using

hermetically packaged, semiconductors, chip resistors, and chip

capacitors on thin film alumina substrates. The bias circuits

are constructed using thick film alumina substrates hermetically

packaged semiconductors, chip resistors and chip capacitors.

5-55.
Ford Aerospace &

Communications Corporation

Mechanical Parameters

Mass 1.4 kg

Volume 140 cu in

Using high risk technology, the 4 GHz amplifier will be updated

with the latest dual gate GasFet's. The mixer should be integrated

with bandpass filtering. This will enhance the mixer performance by

improving gain flatness over temperature and reducing test time.

The crystal oscillator will be replaced by a dielectric resonator

oscillator. The DRO will reduce complexity and cost. The current

upconverter uses an analog circuit to temperature compensate

upconverter gain. Future upconverters should use a digital system to

improve gain stability. The amplifier. DRO. and digital temperature

compensation require development that is geared toward space

qualification. The power consumption will be reduced to 4.0 watts

primarily by the use of the DRO.

The use of the dielectric oscilators will reduce the size of the

upconverter. The number of subassemblies can be reduced from 3 to

2. These would be a DC/DC converter and front end/local oscillator.

Mechanical Parameters

Mass 0.7 kg

Volume 45 cu in

5.2.3.3.5 20 GHZ-75 Watt TWTA

The TWTA technology for this application is at the forefront of

TWT technology today. Current TWT's achieve efficiencies on the

order of 40% and power supplies are the same as the Ku-Band;

i.e.. approximately 90%. Higher TWT efficiencies will be

realized with helix velocity taper and collector optimization.

Also, the use of linearizers as part of TWTA packages will

provide additional improvement in TWT efficiency, and this will

yield TWT efficiencies in the 45% range. High risk technology

utilizing multi-stage, advanced carbon, coated dispenser, or

5-56
Ford Aerospace &

Communications Corporation

mixed metal cathodes, all requiring improved thermal interface

due to the high power density for these small sizes, could

utilize diamond helix support structures to yield efficiencies

greater than 50%. NASA or government funding in this area would

be required to flight qualify these items.

Power supplies, on the other hand, are not likely to improve

much because the magnetic implementation currently limits the

size and weight. Evolutionary changes to supplies with higher

switching rates will yield converter efficiencies in the 92%-93%

range. However, for these high power tubes (200 watts), in large

quantities on the spacecraft, with spacecraft power requirements

of 15-40 kW, an AC coupled main power distribution system could

yield EPC efficiencies on the order of 95-96% by elimination of

the chopper. This would yield a higher overall efficiency for

the spacecraft also, but would require development of the AC

distribution system for the bus.

5.2.3.3.6 20 GHz Output Multiplexers

Using low risk technology, these filters will be constructed

using invar dual mode cylindrical cavity TE 111 filters coupled

together on a common waveguide manifold even though the power

level is 75 watts. The exotic high power techniques used on 50

to 200 watt 11 GHz filters are not required on these 20 GHz

filters because of the wider bandwidth. The wide bandwidth

results in much lower electrical losses and reduces heat

dissipation.

Using high risk technology, the standard waveguide filters will

still be required in 1994. Some improvement in mass should

result from improvements in temperature control and heat sinking

through heat pipes and other means. The improvement could be as

much as 25%. Use of lighter weight materials in the mechanical

design will also contribute to the mass reduction.

5-57
Ford Aerospace &

Communications Corporation

Some effort should be devoted to applying quasi-optical

dielectric filter techniques to the 30 GHz range. It may be

possible to develop filter realizations with very low losses

using reflow or other material that have proven successful for

filters at 60 GHz and higher frequencies.

5.2.3.3.7 Preselect and Harmonic Filters

See 5.2.2.3.5.

5.2.3.3.8 Programmable Frequency Shifters

The high risk technology application of the frequency shifters

allows deletion of approximately a 2/3 portion of the BBP

capacity. The frequency shifters only weigh 10 kg. The concept

here is that the second tier switch becomes the equivalent of a

Tl type of routing; i.e.. 1.5 Mbps in doing this and using the

scanning beam antenna provides the total connectivity to CONUS

coverage. The use of DRO's for the oscillators. GaAs. MMIC for

the switches, and VLSI for the digital control logic will result

in very lightweight, low power equipment to replace significant

BBP capacity by eliminating the need for on-board demodulation,

storage, routing and re-modulation. Currently there is nothing

on the market that performs this function. However certain

military applications do use frequency shifting schemes for

coding. The number and IF frequency here are peculiar to the

commerical space applications and would require NASA/government

subsidy to develop the quantity and speeds required by this

payload architecture.

5.2.4 Ka-Band Scan Payload

5.2.4.1 Overview of Ka-Band Scan Payload

The payload utilizes an agile beam antenna that scans the

entire CONUS coverage area in six segments. The payload provides

5-58
Ford Aerospace &

Communications Corporation

the interconnectivity between the fixed beam traffic discussed in

the prior section and the remaining CONUS area not connected to

the twenty node network. In addition, the payload provides

direct to user GPS service at data rates lower than the trunking

network, and can handle switching on-board down to the circuit

level via the baseband processor. The payload is an all digital.

high data rate, high speed, on-board SS-TDMA architecture. The

downlink burst rate is 480 Mb/s and uplink rates of 240. 120. 60

and 30 Mb/s can be accommodated. The basic system is patterned

after the experimental ACTS system with a capacity of 1.5 Gb/s

per scan beam.

In order to reduce baseband processor capacity and save weight

and power, the second tier switching using high speed programmable frequency shifters was implemented to handle the thin

route trunking portion of the traffic. The fast switching, fast

settling programmable oscillators are an area that would need

further effort and tradeoff. The antenna reflector systems for

this payload are common with the Ka-Band FSS payload while the

feed network is different. The trunking network utilizes 500 MHz

bandwidth channels while the GPS service utilizes 240 MHz

channels.

The six sector scan coverage areas were developed in Section 4

to the SMSA level and £he covered areas converted into latitude

and longitude coordinates for development of the antenna.

Appendix G-2.1 contains the coordinates for each coverage area.

Figure 5.2.4-1 presents the block diagram for the Ka-Band Scan

payload. Table 5.2.4-1 gives the estimated weight, power, and

volume for the low risk (emerging) technology and the high risk

(projected) technology for the transponder and antenna. Also

included in the estimates are the coax, waveguide, and harness

interconnects, plus an estimate for integration hardware to put

the components together and provide necessary brackets for

5-59
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Table 5.2.4-1

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TOLDOUT FRAME

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rord Aerospace &

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Ford Aerospace &

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support and mounting. Not included are any structure or

satellite mounting hardware such as between the feed and

reflector.

5.2.4.2 Ka-Band Scan Antenna Subsystem

The Ka-band scan antenna subsystem provides transmission at 20

GHz and reception at 30 GHz of dual linearly polarized communications signals. The antenna will produce six scanning spot

beams. Each spot beam must scan a separate zone of CONUS as

shown in Figure 5.2.4.-2. Table 5.2.4-2 presents the antenna

subsystem requirements.

Table 5.2.4-2

Ka-Band Scan Antenna Subsystems Requirements

PARAMETERS REQUIREMENTS

Frequency Downlink 17.7 - 20.2 GHz

Uplink 27.5 - 30.0 GHz

Number of 6 scanning beams

Beams

Polarization Dual Sensor

C/I 30 dB

Pointing Pitch Roll 0.02°

Accuracy Yaw 0.04O

The Ka-Band scan antenna and FSS antenna may share the same

reflector aperture. It is assumed that the scan and FSS

frequency bands are separated adequately so that they are able to

be isolated by passive filtering in the satellite and ground

terminals. In addition, it is planned to use different polarizations for the scan and FSS beams. Therefore, both beams can

be operated simultaneously without causing mutual interference.

5-62
(

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5-63
Ford Aerospace &

Comrhunica,tjbns',Co,rporation

The feed array will consist of 500 elements of two-wavelength

square waveguide horns providing coverage, as shown in Figure

5.2.4-3. Some of the horns are connected to an orthoganal linear

polarized orthomode junction (OMJ), a dual port diplexer

providing separate FSS. and scan beams ports. A seven-element

cluster of waveguide horns was chosen to provide low sidelobes

for each beam. Passive ferrite circulator switches and variable

power dividers (VPDs) and variable phase shifters (VPSs) will be

used. Each zone will use the required number of switches and 8

VPDs for the scanning beam. Figure 5.2.4-4 illustrates the

switch/VPD network concept. In the figure, each element is

labeled with a letter of the alphabet between A and H. Each

seven feed cluster will than be connected with a group of

different letters through the- electronically controlled passive

ferrite circular switches. The antenna performance is summarized

in Table 5.2.4-3.

Table 5.2.4-3

Predicted Ka-Band FSS Antenna Subsystem Performance

Parameters Predicted Performance

Peak Gain 50.8 dBi

C/I 30 dB

An alternate approach to the antenna subsystem is to incorporate

a frequency-selective surface in the system as shown in Figure

5.2.4-5. The frequency selective surface is used as a spatial

filter so that the same reflector aperture can be used for both

the transmit and receive bands. Since the frequency ratio is

1.5:1. a single-layered frequency selective surface cannot provide

the required sharp cutoff for this small ratio. A multi-layered

frequency-selective surface is required. The impact of the

multiple-reflected energy in a multiple beam antenna system has

5-64
ORIGSNAL PAGE IS

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Figure 5.2.4-4

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5-66
Ford Aerospace &

Communications Corporation

Figure 5.2-4-5 Frequency Selective Surface Implementation

5-67
Ford Aerospace &

Communications Corporation

to be evaluated to ensure the low cross-polarization required for

a frequency reuse system. These requirements are most stringent,

and the design itself represents the present state-of-art.

The use of an active beam forming network (BFN); i.e.. hundreds

of low power small solid-state monolithic amplifiers distributed

in the BFN to replace the single high power TWT at each beam port,

can be used to improve EIRP and system reliability. However, it

requires two major technology accomplishments. One is the

development of the amplifier module technology for the exit

specification required for this function. The other is the study

and development of a multiple beam antenna optics and microwave

network configuration.

The present weight estimate for this system is about 264 kg.

This weight might be reduced about 20% in 1994 due to the

development of a lighter material for the reflector surface. The

assessment of the technology-critical items are summarized in

Table 5.2.4-4. ;

5.2.4.3 Ka-Band Scan Transponder Subsystem

The Ka-Band Scan Beam Transponder Subsytem consists of four five

channel transponders, and two. six channel transponders.

Channels 1,2 and 3 have a bandwidth of 240 MHz and channels 4.5

and 6 have bandwidth of 500 MHz. Channel switching between beams

and crosslinks to the FSS transponders are accomplished

dynamically by a baseband processor.

The six outputs of the receive beam forming network are fed .to

dedicated receivers via preselector filters. The receivers

amplify and downconvert the received signals to the 4 GHz IF

band. The IF bands of the five channel transponders are subdivided into three 240 MHz channels and two 500 MHz channels by

the input multiplexers, which also provide the required narrow

5-68
Ford Aerospace &

Communications Corporation

band receive filtering responses. The six channel transponders

have an additional 500 MHz channel.

Table 5.2.4-4

The assessment of the level of risk of Critical Technology Items

ITEMS LOW RISK HIGH RISK

Isolation 30 dB 30 dB

Reflectors 62 kg 20% lighter

VPD/VPS Achievable Achievable

Frequency Needs development Achievable

-selective

surface

Active BFN Needs Development Slight Development

The input multiplexers are followed by a baseband processor

which accepts the 4 GHz inputs from all the 240 MHz channels,

downconverts them to baseband and dynamically switches and

reroutes the individual baseband signals. These are then

regrouped, modulated on FM Carriers and upconverted to the 4 GHz

IF. The fourteen 500 MHz channel outputs from the input

multiplexer are routed directly to the FSS Ka-Band transponder

where they are frequency shifted to appropriate bands and

switched to the desired fixed beams by a 20x20 solid state switch

matrix. Fourteen 500 MHz channels from the FSS transponder fixed

beams are also frequency shifted as necessary and switched to the

desired scan beams by the same solid state switch matrix.

The eighteen 240 MHz channel. IF outputs from the baseband

processor and the fourteen 500 MHz channel outputs from the FSS

switch matrix are amplified in variable gain amplifiers, then

5-69
Ford Aerospace &

Communications Corporation

upconverted to 20 GHz. The upconverter output amplifier has the

capability of driving the highest power TWTA (TWTA RF output

ranges from 5 watts to 75 watts) to saturation.

The outputs of the TWTAs are recombined in output multiplexers, which also provide the required narrow band transmit

filtering resonses.

The downlink signals are further filtered by passband and

harmonic filters prior to transmission from the beam forming

network and offset fed cassegrain transmit antenna.

The transponder subsystem features four for two redundancy for

the receivers and five for four redundancy for the upconverters

and TWTAs.

Component description for low risk and high risk technology

are contained in sections 5.2.3.3.1 through 5.2.3.3.8.

5.2.4.4 Baseband Processor

The baseband processor (BBP) subsystem planned for use in this

payload is an advanced version of the Motorola effort that has

been on going since 1980. The BBP. while using less capacity

throughput than the full-up 30/20 GHz system, is operating at

higher data rates and more input channels. Based on low risk

technology, the BBP would still be a development risk due to the

high data rates. The use of the VLSI work in the ECL (MOSAIC)

and CMOS done to date could handle the processing needs once

qualified and demonstrated on ACTS.

Functionally, the BBP. as part of the satellite transponder

system. is required to process. route, and control message

traffic amoung individual users. To this end. the BBP

(1) demodulates the channelized uplink TDMA transmissions.

5-70
Ford Aerospace &

Communications Corporation

(2) transfers the demodulated data on a store-and-forward basis

wherein message segments are accumulated in the output registers

according to their intended destinations. (3) remodulates the

sorted data for downlink transmission (the downlink channelization approaches a pure TDM architecture), and (4) provides

network timing and synchronization. Figure 5.2.4-6 is an overall

concept of the BBP.

The BBP provides the capability to route traffic from any

terminal to any other terminal. It further provides the

capability to distribute GPS traffic on a one-to-several basis.

The BBP utilizes a combination of 4 dB of FEC coding gain and 6

dB improvement in signal-to-noise ratio through the decoding of

the uplinks and encoding of the downlinks. FEC is applied

adaptively only for those terminals degraded by rain. A maximum

total of 125 Mbps of uplink traffic and 125 Mbps of downlink

traffic can be processed as coded traffic. This FEC capacity is

to be apportioned among the terminals as needed. The IF

frequencies are nominally in the range of 3 to 4 GHz. The system

throughput capacity is nominally 9 Gbps.

Figure 5.2.4-7 breaks down one of the scan beam input/output

channel architecture. Each scan beam can handle 1.5 Gbps on

three 480 Mbps downlink channels. The uplink channels have a

maximum of 1.5 Gbps, and lesser rates reduce the overall system

capacity.

For low risk technology, the ACTS BBP weight, power, and volume

are the basis of the estimate. For the high risk technology, it

is assumed that additional VLSI development and advances in

speed/power would yield lighter weight, lower power and correspondingly lower volume. This is an area where the custom VLSI

work would not likely be done without NASA/government subsidized

effort.

5-71
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5.2.5 Ku-Band FSS Payload

5.2.5.1 Overview of Ku-Band FSS Payload

The payload is similar to the current generation of Ku-Band

payloads being launched from 1985 thru 1988. Thus this would be

a one for one replacement. It utilizes an uplink of 14 GHz and a

downlink of 11 GHz. It has 3 times re-use with one CONUS beam

and an eastern and western coverage area beam, all interconnected

via electronic switches. The payload features a dual gridded

reflector to obtain the polarization purity required for re-use.

The reflector assembly is stacked with a slight offset in focal

point for physical separation of the feed assemblies. The transponder is of straight forward design and no on-board processing

is provided. The block diagram shown in Figure 5.2.5-1 indicates

TWTA's for the output amplifiers. However, an alternate using

distributed lower power solid state amplifiers in the beam

forming network would lead to improved reliability and eliminate

the wear out mechanisms inherent in TWTA's. The coverage areas

for the East and West beams were developed in Section 4 to the

SMSA level and the convered areas converted into latitude and

longitude coordinates for development of the antenna. Appendix

G-3.1 contains a listing of the beam coverage areas for each

beam. Table 5.2.5-1 shows the estimated weight, power and volume

for low risk (emerging) technology and high risk (projected)

technology for the transponder and antenna. Also included in the

estimate are the coax, waveguide, and harness interconnects plus

a estimate for integration hardware to put the components

together and provide necessary brackets for support and

mounting. This does not include any structure or satellite

mounting hardware such as between the feeds and the reflectors.

5.2.5.2 Ku-Band FSS Antenna Subsystem

The Ku-Band FSS antenna subsystem provides transmission at 11

GHz and reception at 14 GHz of dual linearly polarized

5-74
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ORIGINAL PAGE IS

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Table B.2.5--2

Scenario II - Payioad Summary

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t/n 5-76

HOLDOUTFord Aerospace &

Communications Corporation
Ford Aerospace &

Communications Corporation

communications signals. The antenna coverage regions include

horizontal polarization for full CONUS and vertical polarization

for east and west half CONUS as shown in Figure 5.2.5-2. The

requirements of the antenna subsystem are summarized in Table

5.2.5-2

The antenna will consist of two overlapped, gridded reflectors

and two multihorn feed array systems, as depicted in Figure

5.2.5-3. The grids of the reflector are selected to run either

in the horizontal on vertical direction for horizontal or

vertical polarization. They are used to help lower crosspolarization energy that is produced by the field curvature of

the asymetric paraboloid, as well as the cross-polarization

radiated from the feed array. The polarization isolation

achieved is greater than 30 dB. In order to provide adequate

reliable isolation between the east and west CONUS beams for

frequency reuse, the size of the reflector should be at least

13'. Figures 5.3.5-4 to 5.2.5-6 present the antenna radiation

patterns for full CONUS beam, and east and west CONUS beams. The

predicted edge-of-coverage antenna gains are given in Table

5.2.5-3.

Table 5.2.5-2

Ku-Band FSS Antenna Subsystem Requirements

Parameters Requirements

Frequency: Transmit: 11 GHz Band

Receive: 14 GHz band

Polarization Full CONUS: Horizontal

East/West Half CONUS: Vertical

Coverage Full CONUS;

Area East/West half CONUS

Isolation: 30 dB

5-77
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5-78
Ford Aerospace & „> ,t

Communications Corporation

,- - . ' •/ ; "~v M •»

Figure 5.2.5-3 Ku-Band FSS Antenna Configuration

5-79
Ford Aerospace &

Communications Corporation ORIGINAL PAGE JS

OF POOR QUALITY

Figure 5.2.5-4 Ku-Band FSS CONUS Antenna Pattern

MflX.

THETfi

4.00 0

CONTOU R DRTfl

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F -25,00 0

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5-80
?a

8

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Ford Aerospace &

Communications Corporation

Figure 5.2.5-6 Ku-Band FSS Western Antenna Pattern

CONTOUR DRTfl

SYMBOL LEVEL

fl

B

C

D

E

F

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-3.000

-6.000

-10.000

-15.000

-20.000

-25.000

-30.000

-35.000

(29.7 dBI.)

5-82
Ford Aerospace &

Communications Corporation

Table 5.2.5-3

Ku-Band FSS Predicted Antenna Gain

Coverage Gain (dBi)

Full CONUS 29

East Half CONUS 35.2

West Half CONUS " 29.7

Diurnal and seasonal solar variations can cause temperature

extremes and gradients on the reflector surface, which in turn

mechanically distort the reflector and degrade the electrical

performance. Advanced Kevlar fiber composite materials are

used for the structural elements of the reflector assembly to

provide maximum thermal stability and structural strength with

minimum weight. Each reflector is a Kevlar/epoxy laminate

sandwich thin shell bonded to a backside on ring reinforced

structure. The sandwich shell supports the gridded system of

wire. The largest existing dual gridded reflector that has

even been built is 6 ft. The proposed size, 13 ft of reflector

aperture, thus presents a challenging mechanical and electrical

design problem in order to provide the required mechanical

stiffness and strength in the present state-of-art technology.

A shared feed approach is proposed in the feed array of the

multiple-beam antenna system. Conventionally, the shaped beam

for east CONUS coverage is formed by a feed array of group 1;

for the west half CONUS coverage, a feed array of group 2.

Group 1 and group 2 do not have any feed in common. A shared

feed system is one that has feed horns shared by the two

groups. The number of available feeds for each coverage is

increased. The sidelobe levels are lower because of better

beam shaping. However, the losses of the beam forming network

are higher. This kind of beam forming network tends to be

frequency sensitive.

5-83
Ford Aerospace &

Communications Corporation

Table 5.2.5-4 summarizes the assessment of the critical

technology items for this subsystem.

Table 5.2.5-4

Assessment of the Level of Risk of Critical Technology Items

Items Low Risk High Risk

Cross-pol isolation 30 dB 33 dB

Co-pol isolation 25 dB 27 dB

Feed array Needs development Achievable

(Shared feed)

Reflector Needs development Achievable

Weight(Reflector) 18.6 kg 20% less

5.2.5.3 Ku-Band FSS Transponder

The Ku-Band Transponder Subsystem consists of three crosslinked

8 channel transponders, each of the 24 channels having a

bandwidth of 54 MHz. The three 8 channel transponders each

utilize the same 500 MHz FSS band, having an uplink at 14 GHz and

downlink at 11 GHz. The transponder subsystem has three inputs,

one each from the Eastern and Western beam-forming networks

(horizontally polarized), and one from the CONUS beam forming

network (vertically polarized). Each of the three 14 GHz inputs

is filtered by an input preselector, then amplified and down

converted to 11 GHz by the receiver. The receiver output is fed

to an input multiplexer which subdivides the 500 MHz IF band into

eight 54 MHz channels.

The three input multiplexers are followed by eight. 3x3 switch

matrices. The latter permit signals in any uplink channel

received via the Eastern region. Western region or CONUS beam

forming networks (BFN) to be re-transmitted via the appropriate

BFN to either the same region or to one of the other two regions.

5-84
Ford Aerospace &

Communications Corporation

Each of the 24 channels is individually amplified by a driver

amplifier, which contains one or more variable gain amplifiers.

The latter permit automatic accommodation of varying uplink

levels using an AGC loop, and also up to 16 dB of power amp back

off via ground control. For the Ku-Band fixed satellite service.

50 watt TWTAs are necessary to ensure sufficient EIRP. The

outputs of the TWTAs in each set of eight channels are combined

in an output multiplexer, and filtered by a harmonic/bandpass

filter prior to transmission from the appropriate' antenna.

The transponder subsystem features 6 for 3 redundancy for the

receivers and 5 for 4 redundancy for the TWTAs.

5.2.5.3.1 14/11.GHz Receiver

Using low risk technology this receiver provides for low noise

amplification at 14 GHz. It down converts 14 GHz to 11 GHz with

a Schottky diode mixer. The mixer is followed by bandpass

filtering and amplification at 11 GHz. The local oscillator is a

temperature controlled crystal oscillator followed by a

multiplier chain.

Electrical Performance

Noise Figure 3.5 dB

Gain 70 dB

Output power @ c/3IM=-40dBc 13 dBm

Frequency stability +1/-2 ppm

DC power 9.0 watts

Mechanically the receiver contains four subassembly trays: a

front end. a driver.a local oscillator and a DC/DC converter.

The trays are assembled in a vertical stack. RF signal

connections between the front end. driver, and local oscillator

trays are made with short loops of semi-rigid coaxial cable.

5-85
Ford Aerospace &

Communications Corporation

A selectable coaxial attenuator is included in the RF signal path

at the input to the driver to allow for adjustment of the overall

gain. Regulated DC voltages are supplied to the front end.

driver and local oscillator trays through a DC harness running

vertically along the side of the stack.

The microwave .tray is an aluminum chassis that contains

substrate assemblies that are bonded into the chassis and

substrate/carrier assembles that are bolted in the chassis. The

substrate assemblies consist of MIC isolators, filters and

temperature compensation. The substrate/carrier assemblies are

MIC amplifiers. The amplifiers are constructed using

hermetically packaged semiconductors. chip resistors, and chip

capacitors on this film, alumina substrates. The b.ias circuits

are constructed using thick film alumina substrates, hermetically

packaged semiconductors, chip resistors and chip capacitors.

Mechanical Parameters

Mass 1.8 kg

Volume 175 cu in

Using high risk technology, the 14 GHz preamp will be updated

with the latest low noise GaAs FET. This will improve noise

figure from 3.5 dB to 2.5 dB. The mixer should be integrated

with the bandpass filtering. This will enhance the mixer

performance by improving gain flatness over temperature and

reducing test time. The 4 GHz amplifiers should be replaced by

monolithic gain blocks. These gain blocks are common to this

receiver and many other applications. This would reduce test

time and improve overall receiver performance. The crystal

oscillator chain could be replaced by a dielectric resonator

oscillator. The DRO will reduce complexity and cost. The

current receiver uses an analog circuit to temperature

compensate the receiver gain. Future receivers should use a

digital system to improve gain stability. The preamp.

5-86
Ford Aerospace &

Communications Corporation

mixer/filter. DRO. and digital temperature compensation require

development that is geared toward space qualification. The 11

GHz gain block would be developed in the commerical market and

could be space qualified. Power consumption will be reduced to

6.0 watts primarily by the use of the DRO.

The use of monolithic gain blocks and dielectric oscilators

will reduce the size of the receiver. The number of

subassemblies can be reduced from 4 to 3. These would be a

DC/DC converter, front end/local oscillator, and driver.

Mechanical Parameters

Mass 0.7 kg

Volume 50 cu in

5.2.5.3.2 11 GHz Input Multiplexers

Using low risk technology TE113 dual mode invar quasi-elliptic

or self-equalized filters would be used for the 24, 36. and 54

MHz wide input filters. They would be coupled together using

coaxial circulators. The 500 MHz filters would be realized

using less exotic filters in order to reduce complexity, size and

mass. Standard rectangular waveguide or coaxial cavities might

be used depending on the specifications. Since the 500 MHz

channels have significantly lower loss, dielectric resonators

could possibly be used to reduce the weight and size even further.

Using high risk technology, it is anticipated that by 1994

dielectrics will be available that give excellent performance at

11 GHz. Today there are materials available that give Qs

exceeding 10.000. Development efforts need to be spent in

establishing mechanical mounting configurations that will not

significantly degrade the filter losses and still hold the

resonator rigidly in place. Use of these filter will reduce the

mass and size of the input multiplexers by a factor of three.

5-87
Ford Aerospace &

Communications Corporation

The impact on satellite size can be very significant if there are

a large number of these filters required per system.

The development plans for 4 GHz dielectric resonator input

multiplexers and their integration with monolithic circuits

applies equally well to the 11 GHz designs. The problem at 11

GHz is more difficult and should be.studied concurrently with the

4 GHz problem in an effort to ready this technology for

applications in 1994.

In addition, methods of mounting dielectric resonators without

degrading electrical performance are even more critical at 11 GHz

than 4 GHz. Several approaches must be conceived and evaluated

in order to have successful implementation available for 1994.

The potential improvement is at last a times three reduction in

size and mass.

5.2.5.3.3 RF Switch Matrix

See Section 5.2.3.3.3.

5.2.5.3.4 12 GHz Driver

Using low risk technology, the 12 GHz driver amplifier would

use dual-gate FETs to provide variable gain amplification. The

voltage applied to the second gate establishes the gain. Chip

FET devices are used to eliminate package parasitics which at

this frequency would degrade the performance and make it difficult

to achieve the desired gain flatness over a range of gain

settings. As a result of using unpackaged devices, the amplifier

module must be hermetically sealed. The RF circuitry is etched

in thin film metalization on alumina substrates which are bonded

to moly or Kovar carriers. The amplifier module is integrated in

the housing with drop-in microstrip isolators to assure good

input and output VSWR's.

5-88
Ford Aerospace &

Communications Corporation

Using high risk technology, rapid advances in gallium arsenide

technology and monolithic microwave integrated circuits should

make it possible to realize several stages of low level,

voltage-controllable gain on a single chip. leading to a

significant reduction in size and weight. It is expected that

achieving the required performance in a monolithic form will

require significant development risk and cost.

5.2.5.3.5 11 GHZ - 50 Watt TWTA

The TWTA technology for this application is reasonably mature.

Current TWT's achieve efficiencies on the order of 45 to 50% and

power supply efficiencies in the 88-90% range are common place.

Higher TWT efficiencies will be realizied with helix velocity

tapers and collector optimization. There is also a trend toward

using linearizers with the TWTA package, which will provide

additional improvement in TWT efficiency and phase shift. This

will yield TWT's with approximately 50% efficiency. The above

changes are evolutionary and low risk. High risk improvements

could lead to efficiencies in the 65% range for the TWT utilizing

advanced carbon cathodes, coated dispenser cathodes or mixed

metal cathodes. This would also yield lifetimes greater than 10

years. To achieve the high efficiency, use of diamond rods to

replace the BeO rods would be required. The processing of these

TWT's requires development.

Power supplies on the other hand are not likely to improve much

because the magnetics currently limit the size and weight.

Evolutionary change to supplies with higher switching rates will

yield converter efficiencies in the 92-93% range.

5.2.5.3.6 11 GHz Output Multiplexers

Using low-risk technology, the 11 GHz output multiplexers will

consist of manifold coupled TE 113 cylindrical cavity quasielliptic filters using two orthogonal modes per cavity for two

5-89
Ford Aerospace &

Communications Corporation

resonators. The filters will be constructed of invar for

temperature stability using the mechanical design approach

developed on the Intelsat V IBS program for the 10 and 20 watts

units.

The 50 and 100 watt units will also be invar, but they will use

the TE114 cylindrical mode in order to reduce the heat dissipated

and the electronic loss. Adequate heat sinking will be provided

to maintain operating temperatures below 100 degrees C. The

basic techniques have been developed on internal development

programs for high power direct broadcast applications.

Using high risk technology, dielectric resonators should be

available for use at 11 GHz in applications of 10 and possibly 20

watts. The construction techniques will be similar to that used

in 4 GHz output filters, with dual mode resonators inside

aluminum housings. This work could result in a mass and size 1/3

that available today.

At power levels of 50 to 200 watts, standard waveguide filters

will still have to be used in 1994. If the heat level and

associated temperature can be accurately controlled, it may be

possible to use lighter materials than invar to minimize

frequency shift with temperature. Improvements in heat sinking

through heat pipes and other means should reduce the mass by as

much as 25%.

Techniques for minimizing temperature variations in these high

power multiplexers should be studied over the next two years in

order to establish the basic approaches that must be developed

for application in 1994.

5.2.5.3.7 Pre-Select and Harmonic Filters

See 5.2.2.3.5.

5-90
Ford Aerospace &

Communications Corporation

5.2.6 Ku-Band DBS Payload

5.2.6.1 Overview of Ku-Band DBS Payload

This payload is a medium power. 100 watt. Ku-band DBS payload

similar to some recent filings with the FCC. The described

payload could be a replacement for one of those payloads. It

utilizes an uplink at 17 GHz and a downlink at 12 GHz. It has

eight 24 MHz channels for each of the eastern and western beam

coverage areas. It provides overlapping coverage since the eight

channels in each beam are separated by frequency. The simplified

block diagram is shown in Figure 5.2.6-1. TWTA's are used at the

100 watt level. However, an alternate approach using distributed

lower power, solid state amplifiers, in the beam forming network

would lead to improved reliability and eliminate the wear out

mechanisms inherent in TWTA's.

Table 5.2.6-1 shows the estimated weight, power, and volume for

low risk (emerging) technology and high risk (projected)

technology for the transponder and antenna. Also included in the

estimates are the coax, waveguide, and harness interconnects,

plus an estimate for integration hardware to put the components

together and provide necessary brackets for support and

mounting. Not included are any structure or satellite mounting

hardware, such as between the feed and reflector.

5.2.6.2 Ku-Band DBS Antenna Subsystem

The Ku-band DBS antenna subsystem provides transmission at 12

GHz and reception at 17 GHz of dually circular-polarized

communication signals. The purpose of the communication antenna

is to provide direct coverage to one of the two areas of CONUS as

shown in Figure 5.2.6-2. Table 5.2.6-2 summarizes the antenna

subsystem requirements.

5-91
co

WCOOu<Qe<vowiVO• (M• Ul a;u3

5-92
Table 5.2.6-1

ORIGINAL PAGE JS

OF POOR QUALfTY

Scenario II - Pavload Summary

Ku-Band DBS

ORIGINAL PAGE »S

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1ARMONIC FILTER

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FOiDOUT

Ford Aerospace &

Communications Corporation
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5-94
Ford Aerospace &

Communications Corporation

Table 5.2.6-2

Ku-Band DBS Antenna Subsystem Requirements

Parameter Requirements

Frequency Transmit: 12 GHz band

Receive: 17 GHz band

Polarization Dual circular polarization

Coverage East/West Half CONUS

Area

Isolation 27 dB

The antenna will consist of two solid, offset parabolic

reflectors, one 2.5 meter for transmit and one 1.9 meter for

receive, as depicted in Figure 5.2.6-3. Each reflector will be

illuminated 'by an array of 55 individual feed horns which are

excited from two input ports through a feed network consisting of

a series of cascaded hybrid power dividers. A polarizer is

employed at each horn to produce circular polarization. Figures

5.2.6-4 and 5.2.6-5 present the antenna radiation patterns.

Table 5.2.6-3 shows the predicted antenna gain of the system.

Table 5.2.6-3

Ku-Band DBS Predicted Antenna Gain

Coverage Gain (dBi)

East Half CONUS 31.4

West Half CONUS 29.8

All technologies required in this system are well developed.

The level of risk of the technology is low. The estimated weight

of the two reflectors is 20 kg. The reflector design is a

graphite epoxy laminate sandwich shell bonded to a backside

5-95
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5-96
Ford Aerospace &

Communications Corporation ORIGINAL PAGE IS

OF POOR QUALITY

Figure 5.2.6-4 Ku-Band DBS Western Antenna Pattern

CONTOUR DRTR

SYMBOL LEVEL

fl

B

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D

E

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-3.000

-6.000

-10.000

-15.000

-20.000

-2.5.000

-30.000

-35.000

(29.8 dBi.)

5-97
Ford Aerospace &

Communications Corporation

ORIGINAL PAGE IS

OF POOR QUALITY

Figure 5.2.6-5 Ku-Band DBS Eastern Antenna Pattern

CONTOUR onin

SYMBOL LEVEL

fl

B

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H

-3.000

-6.000

-10.000

-15.000

-20.000

-25.000

-30.000

-35.000

(31.4 dBi.)

5-98
Ford Aerospace &

Communications Corporation

reinforcing rib structure. The weight could be reduced about 20%

by 1994 due to the current development of a more advanced

graphite material for the reflector surface.

5.2.6.3 Ku-Band Transponder Subsystem. Direct Broadcast Service

The DBS Transponder Subsystem consists of two crosslinked 8

channel transponders, each of the 16 channels having a bandwidth

of 24 MHz. The two 8 channel transponders utilize the same 500

MHz FSS band, having an uplink at 17 GHz and downlink at 12 GHz.

but occupy alternate channel slots. The two transponders

receive their inputs from the eastern and western coverage beam

forming networks of the RHCP antenna feed assemblies. Each of

the two 17 GHz inputs are filtered by an input preselector, then

amplified and downconverted to 4 GHz by the receiver. The

receiver output is fed to an input multiplexer which subdivides

the 500 MHz IF band into eight 24 MHz channels. . Since one of the

receiver local oscillators is offset by one channel spacing from

the other, the IF channel frequencies are the same for both

transponders. The three input multiplexer are followed by eight

transfer switches. The latter permit any uplink channel received

via either the eastern region or western region beam forming

network (BFN) to be re-transmitted via the appropriate BFN to

the same region or to the other region.

Each of the 16 channels is individually upconverted to 12 GHz

and then amplified by a driver amplifier which contains one or

more variable gain amplifiers. The latter permit automatic

accommodation of varying uplink levels, using an AGC loop, and

also up to 16 dB of power amp back-off via ground control. For

the Ku-Band direct broadcast service. 100 watt TWTAs are

necessary to ensure sufficient EIRP. The outputs of the TWTAs in

each set of eight channels are combined in an output multiplexer,

then filtered by a harmonic/band pass filter prior to

transmission from the transmit antenna via the appropriate BFN.

5-99
Ford Aerospace &

Communications Corporation

The transponder subsystem features 2 for 1 redundancy for the

receivers and 5 for 4 redundancy for the TWTAs.

5.2.6.3.1 17/4 GHz Receiver

Using low risk technology this receiver provides for low noise

amplification at 17 GHz. It down converts 17 GHz to 4 GHz with a

Schottfcy diode mixer. The mixer is followed by bandpass filtering

and amplification at 4 GHz. The local oscillator is a temperature

controlled crystal oscillator followed by a multiplier chain.

Electrical Performance

Noise figure 4.0 dB

Gain 70 dB

Output power @ c/3 IM = -40 dBc +13 dBm

Frequency stability +1/-2 ppm

DC power 9.0 watts.

Mechanicaly the receiver contains four subassembly trays: a

front end, a driver, a local oscillator, and a DC/DC converter.

The trays are assembled in a vertical stack. RF signal

connections between tire front end, driver and local oscillator

trays are made with short loops of semirigid coaxial cable. A

selectable coaxial attenuator is included in the RF signal path

at the input to the driver to allow for adjustment of the overall

gain. Regulated DC voltages are supplied to the front end,

driver and local oscillator trays through a DC harness running

vertically along the side of the stack.

The microwave tray is an aluminum chassis that contains

substrate assemblies that are bonded into the chassis and

substrate/carrier assemblies that are bolted in the chassis. The

substrate assemblies consist of MIC isolators. filters and

temperature compensation. The substrate/carrier assemblies are

MIC amplifiers. These amplifiers are constructed using

5-100
Ford Aerospace &

Communications Corporation

hermetically packaged semiconductors, chip resistors, and chip

capacitors on thin film alumina substrates. The bias circuits

are constructed using thick film alumina substrates,

hermetically packaged semiconductors, chip resistors and chip

capacitors.

Mechanical Parameters

Mass 1.8 kg

Volume 175 cu in

Using high risk technology the 17 GHz preamp will be updated

with the latest low noise GaAs FET. This will impove the noise

figure from 4.0 dB to 2.5 dB. The mixer should be integrated

with the bandpasss filtering. This will enhance the mixer

performance by improving gain flatness over temperature and

reducing test time. The 4 GHz amplifiers should be replaced by

monolithic gain blocks. These gain blocks are common to this

receiver and many other applications. This would reduce test

time and improve overall receiver performance. The crystal

oscillator chain could be replaced by a dielectric resonator

oscillator. The DRO will reduce complexity and cost. The

current receiver uses an analog circuit to temperature compensate

the receiver gain. Future receivers should use a digital system

to improve gain stability. The preamp. mixer/filter. DRO, -and

digital temperature compensation require development that is

geared toward space qualification. The 4 GHz gain block would be

developed in the commerical market and could be space qualified.

Power consumption will be reduced to 6.0 watts primarily by the

use of the DRO.

The use of monolithic gain blocks and dielectric oscillators

will reduce the size of the receiver. The number of subassemblies can be reduce 4 to 3. These would be a DC/dc

converter, front end/local oscillator, and driver.

5-101
Ford Aerospace &

Communications Corporation

Mechanical Parameters

Mass 0.9 kg

Volume 50 cu in

5.2.6.3.2 4 GHz Input Multiplexer

See 5.2.2.3.2.

5.2.6.3.3 R.F. Switch Matrix

See 5.2.3.3.3.

5.2.6.3.4 4 GHz/11. 12 GHz Upconverter

Using low risk technology. this upconverter provides for

amplification at 4 GHz. It up converts 4 GHz to 11 or 12 GHz

with a Schottky diode mixer. The mixer is followed by bandpass

filtering. The local oscillator is a temperature controlled

crystal oscillator followed by a multiplier chain. The 4 GHz

amplification is done with dual gate FET's that also provide

variable or stepped gain control.

Electrical Performance

Gain 15 dB

Output power @ c/3IM = -40dBc -10 dBm

Frequency stability +1/-2 ppm

DC power 7.0 watts

Mechanicaly the upconverter contains three subassembly trays:

a front end. a local oscillator and a DC/DC converter.

The trays are assembled in a vertical stack. RF signal

connections between the front end. and local oscillator trays are

5-102
Ford Aerospace &

Communications Corporation

made with a short loop of coax cable. Regulated DC voltages are

supplied to the front end. and local oscillator trays through a

DC harness running vertically along the side of the stack.

The microwave tray is an aluminum chassis that contains:

substrate assemblies that are bonded into the chassis and

substrate/carrier assemblies that are bolted in the chassis. The

substrate assemblies consist of MIC isolators, filters and

temperature compensation. The substrate/carrier assemblies are

MIC amplifiers. These amplifiers are constructed using

hermetically packaged semiconductors, chip resistors, and chip

capacitors on thin film alumina substrates. The bias circuits

are constructed using thick film alumina substrates, hermeticaly

packaged semiconductors, chip resistors and chip capacitors.

Mechanical Parameters

Mass 1.4 kg

; Volume 140 cu in

Using high risk technology, the 4 GHz amplifier will be updated

with the latest dual gate GaAs FET. The mixer should be

integrated with bandpass filtering. This will enhance the mixer

performance by improving gain flatness over temperature and

reducing test time. The crystal oscillator will be replaced by a

dielectric resonator oscillator. The DRO will reduce complexity

and cost. The current upconverter uses an analog circuit to

temperature compensate upconverter gain. Future upconverters

should incorporate a digital system to improve gain stability.

The amplifier. DRO, and digital temperature compensation require

development that is geared toward space qualification. The power

consumption will be reduced to 4.0 watts, primarily by the use of

the DRO.

The use of the dielectric oscillators will reduce the size of

the upconverter. The number of subassemblies can be reduce from

• 5-103
Ford Aerospace &

Communications Corporation

3 to 2. These would be a DC/DC converter and front end/local

oscillator.

Mechanical Parameters

Mass 0.4 kg

Volume 45 cu in

5.2.6.3.5 12 GHz - 100/200 Watt TWTA

The TWTA technology for this application is reasonably mature.

Current TWT's achieve efficiencies on the order of 45 to 50%, and

power supplies in the 88-90% range are commonplace. Higher TWT

efficiencies will be realizied with helix velocity tapers and

collector optimization. There is also a trend toward using

linearizers with the TWTA package, which will provide additional

improvement is TWT efficiency and phase shift. This will yield

TWT's with 50-55% efficiency. The above changes are evolutionary

and low risk. High risk improvements could lead to efficiencies

in the 65% range for the TWT utilizing advanced carbon cathodes,

coated dispenser cathodes, or mixed metal cathodes. To achieve

the high efficiency, use of diamond rods instead of the BeO rods

would be required.

Power supplies on the other hand are not likely to improve much

as the magnetics currently limit the size and weight.

Evolutionary change to supplies with higher switching rates will

yield converter efficiencies in the 92-93% range. However, for

these high power TWTAs in large quantities on the satellite,

(i.e.. spacecraft of 15 - 40 kW), an AC coupled main power

distribution system could yield EPC efficiencies on the order of

95-96% by elimination of the chopper. This would yield a higher

overall efficiency for the spacecraft also, but would require

development, of the AC distribution system for the bus.

5-104
Ford Aerospace &

Communications Corporation

5.2.6.3.6 12 GHz Output Multiplexer

See 5.2.5.3.6.

5.2.6.3.7 Pre-Select and Harmonic Filters

See 5.2.2.3.5.

5-105
Ford Aerospace &

Communications Corporation

5.3 SCENARIO IV DEFINITION

5.3.1 Introduction

Scenario IV can be described as a high capacity, high power

video distribution satellite containing a replacement for a

current version Ku-Band FSS payload, and a new direct to home

Ku-Band DBS payload. Each payload is broken down to 24 MHz

bandwidth channels to allow interconnectivity between bands for

on-board networking. The.services provided are listed below:

o 48 Channels, medium power. Ku-band. FSS payload

3 beams - 1 CONUS & 2 regional CONUS

16 channels per beam

3 x re-use.

o 64 channels, high power, Ku-band. DBS payload

4 beam - time zone

r 16. channels per beam

4 x re-use

o Interconnectivity for half the channels from

FSS to DBS

The on-board interconnectivity for half of the channels

provides the networking necessary for a broadcast mode, one

uplink to all downlinks, or one uplink to each downlink. This

flexibility eliminates the ground cut ins and outs and also

allows ground uplink sources to have only one antenna for both

cable and direct to home distribution on only one satellite.

An overview block diagram of the payload elements is shown in

Figure 5.3.1-1. Table 5.3.1-1 lists the major scenario bus

interface requirements and Table 5.3.1-2 and 5.3.1-3 present the

major antenna and transponder characterictics respectively. The

antennas will be rigidly mounted to the body and body steered via

the bus control system.

.5-106
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5-107
Ford Aerospace &

Communications Corporation

Table 5.3.1-1

Scenario IV - Payload Summary

o Mass

o Power Required

Sunlight

Eclipse

o Pointing Requirement

o Temperature Requirements

Antenna

Transponder

o Thermal Dissipation

o Life Time

1616 kg

35.035 watts

50% min; 75% desired

+ 0.05° absolute (ie: RF

boresight)

-90° to +11QOC

-10°C to +59<>C. TWTA'S

+ 6QOC

1.5 kW in EPC's, 8 kW in

TWT's s, 4 kW in feeds &

w/g losses

10 year without servicing

Table 5.3.1-2

Scenario IV Antenna Configuration

Antenna

System

Freq

(GHz) Reflector Polarization Feed Arrays

Ku-Band 17/12 one 8' (2.44m)

DBS solid reflector/

one 6' (1.8)

solid reflector

CP 2x55 feeds

plus

2x55

polarizers

Ku-Band 14/11 13'(4m) dual

FSS gridded reflector

Linear 2x334

feeds.

5-108
Ford Aerospace &

Communications Corporation

Table 5.3.1-3

Transponder Summary Scenario IV

U/L.D/L Number Channel RCVR Type HPA Type HPA

Payload Frez. GHz Channels BW. R/F (Number) Number Power,

Ku Band 17/12

DBS

64 24 17/4 TWTA(80) 200

Ku Band 14/11

FSS

48 24 14/4 TWTA(60) 50

Due to the use of TWTA's foe the Ku-band FSS and DBS payloads.

a 10 year life is all that can be envisioned at this time.

Replacement of TWTA's at GEO or return of the payload from GEO

for servicing and replacement of TWTA's is not anticipated for

the early 2000 time period. It is estimated that the identified

redundancy is compatable with a 10 year life application.

If lower risk technology is utilized, it is possible that fuel

servicing at GEO or perigee augmentation at LEO could be utilized

to maintain the Launch Concept 1 status of the payload.

Table 5.3.1-4 presents a summary of the high and low risk

weight and power for the individual payload elements in Scenario

IV.

In Appendix H. Tables 1 thru 4 show that all of the payload

elements have viable links with the various types of anticipated

modulation and access types. While some of the margins are low,

the links represent the worst case condition. and if this

scenario were to be studied further for full system definition,

it is expected that the link margin could be improved for actual

implementation.

5-109
Ford Aerospace &

Communications Corporation

Table 5.3.1-4

Scenario IV - Weight and Power

Ku-Band FSS

Transponder

Antenna

Sub Total

WEIGHT(KG) . POWER(W)

Low Risk High Risk Low Risk High Risk

624.3

126.5

750.8

496

108.5

604.5

7052

7052

5075

5075

Ku-Band DBS

Transponder

Antenna

Sub Total

1194

33

1227

984

27.5

1011.5

34060

34060

29960

29960

SCENARIO IV TOTAL 1977.8 1616 41112 35035

5-110
Ford Aerospace &

Communications Corporation

5.3.2 Ku-Band FSS Payload

5.3.2.1 Overview of Ku-Band FSS Payload

The payload. while similar to the FSS payload described in

5.2.5 is different in that it uses 24 MHz bandwidth channels

rather than 54 or 36 MHz channels. This is to tailor this

payload to the video distribution characteristics and be

switchable to the DBS band for on-board networking. This payload

still has a 3 times re-use with respect to CONUS coverage, with

one full CONUS beam, and two regional, eastern and western

coverage area, beams.

The payload features a dual gridded reflector to obtain the

polarization purity required for re-use. The reflector assembly

is stacked with a slight offset in focal point for physical

separation of the feed assemblies. The transponder is straight

forward design and no on-board processing is provided. The block

diagram shown in Figure 5.3.2-1 indicates TWTA's for the output

amplifiers. An alternate approach using multiple lower power

solid state amplifiers in the beam forming network can be

foreseen in the late 1990 's time frame. This would lead to

improved reliability and eliminate the wear out mechanisms

inherent in TWTA's. Table 5.3.2-1 shows the estimated weight,

power and volume for low risk (emerging) technology and high risk

(projected) technology for the transponder and antenna. Also

included in the estimate, are the coax, waveguide, and harness

interconnects, plus an estimate for integration hardware to put

the components together and provide necessary brackets for

support and mounting. This does not include any structure or

satellite mounting hardware, such as between the feeds and the

reflectors.

5-111
ORIGINAL PAGE JS

OF POOR QUALfTY

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5-112
Table 5.3.2-1

ORIGINAL PAGE IS

OF POOR QUALfTY

Scenario IV - Payload Summary

Ku-Band FSS

ORIGINAL PAGE IS

Of POOR QUALITY

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Ford Aerospace &

Communications Corporation
Ford Aerospace &

Communications Corporation

5.3.2.2 Ku-Band FSS Antenna Subsystem

The Ku-Band FSS antenna subsystem provides transmission at 11

GHz and reception at 14 GHz of dually linearly polarized

communications signals. The antenna coverage regions include a

horizontal polarization for full CONUS beam and a vertical

polarization for east and west half CONUS beam as shown in Figure

5.3.2-2. The requirements of the antenna subsystem are

summarized in Table 5.3.2-2

Table 5.3.2-2

Ku-Band FSS Antenna Subsystem Requirements

Parameters Requirements

Frequency: Transmit: 11 GHz Band

Receive: 14 GHz band

Polarization Full CONUS: Vertical

East/West Half CONUS: Horizontal

Coverage Full CONUS;

Area East/West half CONUS

Isolation: 30 dB

The antenna subsystem will consist of two overlapped, gridded

reflectors and two multihorn feed array systems, as depicted in

Figure 5.3.2-3. The grids of the reflector are selected to run

either in the horizontal on vertical direction for horizatal or

vertical polarization. They are used to help lower crosspolarization energy that is produced by the field curvature of an

asymmetric paraboloid, as well as the cross-polarization radiated

from the feed array. The polarization isolation achieved is

greater than 30 dB. In order to provide adequate reliable

isolation between the east and west CONUS beams for frequency

reuse, the size of the reflector should be at least 13'. Figures

5.3.2-4 to 5.3.2-6 present the antenna radiation patterns for the

5-114
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5-115
Ford Aerospace &

Communications Corporation

Figure 5.3.2-3 Ku-Band FSS Antenna Configuration

r

2.0

5-116
Ford Aerospace &

Communications Corporation

OTOSNAL PAGE IS

OE POOR

Figure 5.3.2-4 K«-Band FSS CONUS Antenna Pattern

CONTOUR DflTfl

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-25.000

-30.000

-35.000 .

5-117
Ford Aerospace &

Communications Corporation

ORIGINAL PAGE 5S

OF POOR QUALITY

•Figure 5.3.2-5 Ku-Band FSS Eastern Antenna Pattern

MRX .

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5-118
Ford Aerospace & .

Communications Corporation

Figure 5.3.2-6 Ku-Band FSS Western Antenna Pattern

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-10.00 0

-15,00 0

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-35,000 5-119
Ford Aerospace &

Communications Corporation

full CONUS beam, and the east and west CONUS beams. The

predicted edge-of-coverage antenna gains are given in Table

5.3.2-3.

Table 5.3.2-3

Ku-Band FSS Predicted Antenna Gain

Coverage Gain (dBi)

Full CONUS 29

East Half CONUS 31.9

West Half CONUS 30.7

Diurnal and seasonal solar variations can cause temperature

extremes and gradients on the reflector surface, which in turn

mechanically distort the reflector. and degrade the electrical

performance. Advanced Kevlar fiber composite materials are used for

the structural elements of the reflector assembly to provide maximum

thermal stability and structural strength with minimum weight. Each

reflector is a Kevlar/epoxy laminate sandwich thin shell bonded to a

backside on ring reinforcing structure. The sandwich shell supports

the gridded system of wire. The largest existing dual gridded

reflector that has ever been built is 6 feet. The proposed size. 13

feet of reflector aperture, presents many challenging mechanical,

and hence electrical design problems. to provide the required

mechanical stiffness and strength in the present state-of-art

technology.

A shared feed approach is proposed in the feed array of the

multiple-beam antenna system. Conventionally, the shaped beam for

east CONUS coverage is formed by a feed array of group 1; for the

west half CONUS coverage, a feed array of group 2. Group 1 and

group 2 do not have any feed in common. A shared feed system has

feed horns shared by the two groups. The number of available feeds

for each coverage is increased. The sidelobe levels are lower

because of better beam shaping. However, the losses of the beam

5-120
Ford Aerospace &

Communications Corporation

forming network are higher. This kind of beam forming network

tends to be frequency sensitive.

Table 5.3.2-4 summarizes the assessment of the critical

technology items for this subsystem.

Table 5.3.2-4

Assessment of the Level of Risk of Critical Technology Items

Items Low Risk High Risk

Cross-pol Isolation .30 dB 33 dB

Co-pol Isolation 25 dB 27 dB

Feed Array Needs Development Achievable

(Shared Feed)

Reflector Needs Development Achievable

Weight(Reflector) 18.6 kg 20% less

5.3.2.3 Ku-Band Transponder Subsystem Fixed Satellite Service

The Ku-Band Transponder subsystem consists of three 16 channel

transponders, and hence has a total capacity of 48 channels, each

having a bandwidth of 24 MHz. Channels nine to sixteen of each

transponder are cross-linked at the 4 GHz IF to the same channels

of the four DBS transponders. The three transponders utilize the

same 500 MHz FSS band, having an uplink at 14 GHz and downlink at

11 GHz. The transponder subsystem receives two inputs from the

horizontally polarized feed assembly (Eastern and Western

coverages) and one from the vertically polarized feed assemly

(CONUS coverage). Each of the three 14 GHz inputs is filtered by

an input preselector, then amplified and down coverted to 4 GHz

by the receiver. The receiver output is fed to an input

multiplexer which subdivides the 500 MHz IF band into sixteen 24

MHz channels, while also providing the required narrow band

receive filtering responses.

5-121
Ford Aerospace &

Communications Corporation

The three input multiplexers are followed by eight 7x7 switch

matrices. The latter permit signals in any of the uplink

channels 9 te 16 Eeeeivea1 via the Eastern Eegieft, Western region,

or CONUS beam forming network (BFN). to be re-transmitted via

any of the four DBS transponder output sections and associated

BFNs (Eastern. Mountain, Central and Pacific regions). The

switch matrix also contains hybrids which permit a broadcast

mode of operation.

Each of the 48 channels is individually amplified by a driver

amplifier, which contains one or more variable gain amplifiers.

The latter permit automatic accommodation of varying uplink

levels using an AGC loop..and also up to 16 dB of power amp back

off via ground control. For the Ku Band fixed satellite

service. 50 watt TWTAs are necessary to ensure sufficient EIRP.

The outputs of the TWTAs in each set of sixteen channels are

combined in an output multiplexer, and filtered by a harmonic/

bandpass filter prior to transmission from the appropriate

antenna feed assembly. The transponder subsystem features 2 for 1

redundancy for the receivers and 5 for 4 redundancy for the TWTAs.

5.3.2.3.1. 14 GHZ/4 GHz Receiver

.Using low risk technology, this receiver provides for low

noise amplification at 14 GHz. It down converts 14 GHz to 4 GHz

with a Schottky diode mixer. The mixer is followed by bandpass

filtering and amplification at 4 GHz. The local oscillator is

temperature controlled crystal oscillator followed by a

multiplier chain.

Electrical Performance

Noise figure 3 . 5 dB

Gain 70 dB

Output power @ c/3IM=-40dBc +13 dBm

Freguency stability +1/-2 ppm

DC power 8.0 watts

5-122
Ford Aerospace &

Communications Corporation

Mechanically the receiver contains four subasserably trays: a

front end. a driver, a local oscillator, and a DC/DC converter

The trays are assembled in a vertical stack. RF signal

connections between the front end. driver, and local oscillator

trays are made with short loops of semirigid coaxial cable. A

selectable coaxial attenuator is included in the RF signal path

at the input to the driver to allow for adjustment of the overall

gain. Regulated DC voltages are supplied to the front end.

driver, and local oscillator trays through a DC harness running

vertically along the side of the stack.

The microwave tray is an aluminum chassis that contains

substrate assemblies that are bonded into the chassis, and

substrate/carrier assemblies that are bolted in the chassis. The

substrate assemblies consist of MIC isolators. filters and

temperature compensation. The substrate/carrier assemblies are

MIC amplifiers. The amplifiers are constructed using

hermetically packaged semiconductors, chip resistors, and chip

capacitors on this film alumina substrates. The bias circuits

are constructed using thick film alumina substrates, hermetically

packaged semiconductors, chip resistors and chip capacitors.

Mechanical Parameters

Mass 1.8 kg

Volume 175 cu in

Using high risk technology, the 14 GHz preamp will be updated

with the latest low noise GaAs FET. This will improve the noise

figure from 3.5 dB to 2.0 dB. The mixer should be integrated

with the bandpasss filtering. This will enhance the mixer

performance by improving gain flatness over temperature and

reducing test time. The 4 GHz amplifiers should be replaced by

monolithic gain blocks. These gain blocks are common to this

receiver and many other applications. This would reduce test

5-123
Ford Aerospace &

Communications Corporation

time and improve overall receiver performance. The crystal

oscillator chain could be replaced by a dielectric resonator

oscillator (DRO). The DRO will reduce complexity and cost. The

current receiver uses an analog circuit to temperature compensate

the receiver gain. Future receivers should use a digital system

to improve gain stability. The preamp. mixer/filter. DRO. and

digital temperature compensation require development that is

geared toward space qualification. The 4 GHz gain block would be

developed in the commerical market and could be space qualified.

Power consumption will be reduced to 6.0 watts, primarily by the

use of the DRO.

The use of monolithic gain blocks and dielectric oscillators

will reduce the size of the receiver. The number of

subassemblies can be reduced from 4 to 3. These would be a DC/DC

converter, front end/local oscillator, and driver.

Mechanical Parameters

Mass 0.9 kg

Volume 50 cu in

5.3.2.3.2 4 GHz Input Multiplexer

See 5.2.2.3.2.

5.3.2.3.3 R.F. Switch Matrix

See 5.2.3.3.3.

5.3.2.3.4 4/11 GHz Upconvertor

See 5.2.6.3.4.

5-124
Ford Aerospace &

Communications Corporation

5.3.2.3.5 11 GHZ - 50 Watt TWTA

See 5.2.5.3.5. •

5.3.2.3.6 11 GHz Output Multiplexer

See 5.2.5.3.6.

5.3.2.3.7 Pre-Select and Harmonic Filter

See 5.2.2.3.5.

5.3.3 Ku-Band DBS Payload

5.3.3.1 Overview of Ku-Band DBS Payload

This payload is a high power. 200 watt. Ku-band DBS payload.

It utilizes an uplink of 17 GHz and a downlink at 12 GHz. It has

sixteen 24 MHz channels for each of the four beam coverage

areas. Isolation is provided by alternate use of RHCP and LHCP.

The simplified block diagram is shown in Figure 5.3.3-1. TWTA's

are used at the 200 watt level and it is not likely that at this

power level solid state amplifiers are a viable alternate. The

on-board interconnectivity for eight of the channels allows

networking and eliminates some of the ground switch over

problems. It also provides a broadcast mode of operation to all

seven (4 DBS and 3 FSS) beams with one uplink.

Table 5.3.3-1 shows the estimated weight, power, and volume for

low risk (emerging) technology and high risk (projected)

technology for the transponder and antenna. Also included in the

estimates are the coax, waveguide, and harness interconnects,

plus an estimate for integration hardware to put the components

together and provide necessary brackets for support and

mounting. This does not include any structure or satellite

mounting hardware, such as between the feed and reflector.

5-125
Ford Aerospace &

Communications Corporation ORIGINAL PAOE 8S

OF POOR QUALITY

Figure 5.3.3-1 Scenario IV - Ku-Band DBS Payload

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5-126
Table 5.3-3-1

ORIGINAL PAGE'IS

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5-127

(L FQLDOUT FRAMi

Ford Aerospace &

Communications Corporation
Ford Aerospace &

Communications Corporation

5.3.3.2 Ku-Band DBS Antenna Subsystem

The Ku-band DBS antenna subsystem provides transmission at 12

GHz and reception at 1-7 GHz of dually circularly-polarized

communication signals. The purpose of the communication antenna

is to provide direct coverage to one of the four areas of CONUS

(Eastern. Central Mountain. Pacific). as shown in Figure

5.3.3-2. Table 5.3.3-2 summarizes the antenna subsystem

requirements.

Table 5.3.3-2

Ku-Band DBS Antenna Subsystem Requirements

Parameter

Frequency

Transmit:

Receive:

Polarization

Coverage

Area

Central Service Area

Cross-polarization

Isolation

Requirements

12 GHz band

17 GHz band

Dual circular polarization

Eastern Service Area

Mountain Service Area

Pacific Service Area

27 dB

The antenna will consist of two solid, offset parabolic

reflectors, one 2.44 meter for transmit and one 1.8 meter for

receive, as depicted in Figure 5.3.3-3. Each reflector will be

illuminated by an array of 55 individual feed horns which are

excited from two input ports through a feed network consisting of

a series of cascaded hybrid power dividers. A polarizer is

employed at each horn to produce circular polarization. Figures

5.3.3-4 thru 5.3.3-7 present the antenna radiation patterns.

Table 5.3.3-3 shows the predicted antenna gains of the system.

5-128
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5-130
Ford Aerospace &

Communications Corporation

Figure 5.3.3-4 Ku-Band DBS Eastern Antenna Pattern

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5-131
Ford Aerospace &

Communications Corporation

Figure 5.3.3-5 Ku-Band DBS Central Antenna Pattern

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5-132
Ford Aerospace &

Communications Corporation

Figure 5.3.3-6 Ku-Band DBS Mountain Antenna Pattern

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5-133
Ford Aerospace &

Communications Corporation

Figure 5.3.3-7 Ku-Band DBS Pacific Antenna Pattern

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5-134
Ford Aerospace &

Communications Corporation

Table 5.3.3-3

Ku-Band DBS Predicted Antenna Gain

Coverage Gain (dBi)

Eastern 33.2

Central 33.5

Mountain 32.8

Pacific 33

All technologies required in this system are well developed.

The level of risk of the technology is low. The estimated weight

of two reflectors is 20 kg. The reflector design is a graphite

epoxy laminate sandwich -shell bonded to a backside reinforcing

rib structure. The weight could be reduced by about 20% by 1994

due to the current development of a more advanced graphite

materials for the reflector surface.

5.3.3.3 Ku-Band Transponder. Direct Broadcast Service

The DBS Transponder Subsystem consists of four 16 channel

transponders, and hence has a total capacity of 64 channels,

each having a bandwidth of 24 MHz. Channels 9 to 16 of each

transponder are cross-linked at the 4 GHz IF to the same

channels of the three FSS transponders. The four transponders

utilize the same 500 MHz DBS band, having an uplink at 17 GHz

and downlink at 12 GHz. The transponder subsystem receives two

inputs from the RHCP antenna feed assembly (Eastern and Mountain

coverages) and two inputs from the LHCP antenna feed assembly

(Central and Pacific coverages). Each of the four 17 GHz inputs

is filtered by an input preselector. then amplified and

downconverted to 4 GHz by the receiver. The receiver output is

fed to an input multiplexer which subdivides the 500 MHz IF band

into sixteen 24 MHz channels, while also providing the required

narrow band receive filtering responses.

5-135
Ford Aerospace &

Communications Corporation

The three input multiplexers are followed by eight 7x7 switch

matrices. The latter permits signals in any of the uplink

channels 9 to is (received via the Eastern. Mountain. Central, or

Pacific region beam forming networks(BFN)) to be re-transmitted

via any of the three FSS transponder output sections or/and any

of the four DBS output sections and associated BFNs. The switch

matrix also contains hybrids which permit a broadcast mode of

operation.

Each of the 64 channels is individually upconverted to 12 GHz

and then amplified by a driver amplifier, which contains one or

more variable gain amplifiers. The latter permit automatic

accommodation of varying uplink levels, using an AGC loop, and

also up to 16 dB of power-amp back-off via ground control. For

the Ku-Band direct broadcast service. 200 watt TWTAs are

necessary to ensure sufficient EIRP. The outputs of the TWTAs

in each set of sixteen channels are combined in an output

multiplexer. which also provides the required narrowband

transmit filtering response. The downlink signals are further

filtered by a harmonic/bandpass filter prior to transmission via

the appropriate antenna feed assembly.

The transponder subsystem features 6 for 3 redundancy for the

receivers, and 5 for 4 redundancy for the TWTAs.

5.3.3.3.1 17/4 GHz Receiver

See 5.2.6.3.1.

5.3.3.3.2 4 GHz Multiplexer

See 5.2.2,3.2.

5.3.3.3.3 4/12 GHz Upconverter

See 5.2.6.3.4.

5-136
Ford Aerospace &

Communications Corporation

5.3.3.3.4 12 GHZ - 200 Watt TWTA

See 5.2.6.3.5.

5.3.3.3.5 12 GHz Output Multiplexer

See 5.2.5.3.6.

5.3.3.3.6 Pre-Select and Harmonic Filters

See 5.2.2.3.5.

5-137
Ford Aerospace &

Communications Corporation

5.4 SCENARIO V DEFINITION

5.4.1 Introduction

Scenario V can be described as a high capacity. CONUS. FSS

satellite payload that is designed to meet the distributional

characteristics of CONUS traffic, assuming approximately 60% of

the traffic is digital. The scenario uses all three FSS bands.

C. Ku. and Ka-band. It has static, reconfigurable switch

networks at C and Ku-band. and dynamic switching and baseband

processing at Ka-band. The services provided are listed below:

o 48 Channels, 36 MHz, C-bahd, FSS payload. 4 beams. 12

channels each, 4 x re-use.

o 108 channels 36 MHz. Ku-band, FSS payload, 9 beams, 12

channels each, 9 x re-use.

38 channels, 500 MHz. Ka-band. FSS payload.

approximately 2 channels each, 7.6 x re-use.

20 beams.

o 18 channels of 240 MHz. and 14 channels of 500 MHz. Ka-band.

CPS payload. 6 beams. CPS/thin route trunking. 4.6 x re-use.

The C and Ku-band payloads are designed for primarily high

capacity analog voice trunking. while the Ka-band is an all

digital SS TDMA system using high efficiency modulation

techniques to achieve a 2 bits per hertz capacity. The

satellite can utilize a wide variety of orbital locations.

However, once the Ka-Band antenna spots are determined, only

about ±5 of orbital movement can be accomodated. This may

require 2 or 3 options on the design to allow use of orbital

positions in the U.S. arc.

5-138
Ford Aerospace &

Communications Corporation

An overview block diagram of the payload elements is shown in

Figure 5.4.1-1. Table 5.4.1-1 lists the major bus/payload

interface requirements and Tables 5.4.1-2 and 5.4.1-3 present

the major antenna and transponder characteristics respectively.

The two Ka-Band antennae require individual gimbal systems for

steering the two sub-reflectors to achieve +. 0.02° pointing of

the RF boresight. The other antennae will be rigidly mounted to

the body and body steered via the bus control system.

Table 5.4.1-1

Scenario V - Payload Summary

o Mass

o Power Required

Sunlight

Eclipse

o Pointing Reqmt,

o Temp. Reqmts.

Antenna

Transponder

o Thermal Diss.

o Life Time

2261 kg

7500 watts

75% rain; 100% desired

+ 0.05° absolute (ie: RF

boresight)

-90° to +110°C

-10°C to +50°C. TWTA'S

+60°C

5 kW TWT. 500 W. EPC'S.

1 kW Feeds & W/G

10 years without servicing

Due to the use of TWTA's for the Ka-band FSS payload. a 10

year life is all that can be envisaged at this time.

Replacement of TWTA's at GEO is not anticipated for the early

2000 time period. It is estimated that the identified

redundancy is compatible with a 10 year life application.

5-139
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5-140
Ford Aerospace &

Communications Corporation

Table 5.4.1-2

Scenario V Antenna Configuration

Antenna

System

Freq

(GHz) Reflector Polarization Feed Arrays

C-Band 6/4 15'(4.6m) dual Linear

FSS gridded reflector

Ku-Band 14/11 15'(4.6m) dual Linear

FSS gridded reflector

Ka-Band 30/20 One solid 13' Linear

FSS (4.0m) reflector for tx. one

solid 9'(2.7m.)

reflector for rec

(dual shaped

reflector, each

with subreflector)

2x26 feeds

plus

2x26

diplexers

2X450

feeds.

Tx:500

feeds..

830

switches.

140 orthomode junctions;

same for

receive

Table 5.4.1-3

Transponder Summary Scenario V

U/L.D/L Number Channel RCVR Type HPA Type HPA

Payload Freq. GHz Channels BW(MHz) (Number) (Number) Power.W

C-Band

FSS

Ku-Band

FSS

Ka-Band

FSS

Ka-Band

Scan

6/4

14/11

30/20

30/20

48

108

38

32

36 6/4(8)

36 14/11(18)

500 30/4(40)

240/500 30/4(12)

SSPA(60)

SSPA(135)

TWTA(49)

TWTA(40)

4

2

75

75

5-141
Ford Aerospace &

Communications Corporation

If lower risk technology is utilized, it is possible that fuel

servicing at GEO or perigee augmentation at LEO could be

utilized to bring this payload within the limits of the Launch

Concept 1.

Table 5.4.1-4 presents a summary of the high and low risk

weight and power for the individual payload elements in

Scenario V.

In Appendix 1-3. Tables 1 through 6 show that all of the

payload elements have viable links with the various types of

anticipated modulation and access. While some of the margins

are low. the links represent the worst case conditions. If this

scenario were to be studied further for full system definition,

it is expected that link margins could be improved for actual

implementation.

5.4.2 C-Band FSS Payload

5.4.2.1 Overview of C-Band FSS Payload

This payload doubles the capacity of the current day C-band

payloads by using shaped beam technology. The system uses

horizontal and vertical linear polarization isolation for 2

times reuse and spatial isolation of shaped beams to double the

capacity with respect to CONUS coverage. The beam coverages use

three beams to cover CONUS. and a fourth beam doubling the

re-use in the northeast corner of CONUS. The payload features a

dual gridded reflector assembly to obtain the polarization

purity required for the re-use. Each of the transponder channels

is of straight-forward design, and although electronic switches

are used for routing, it is only for traffic pattern changes and

only used on a limited basis. It does, however, also provide

the flexibility to use the system as a SS-TDMA digital modulation if so desired. Figure 5.4.2-1 is a block diagram of the

C-Band FSS payload for Scenario V showing the breakdown to the

5-142
Ford Aerospace &

Communications Corporation

Table 5.4.1-4

Scenario V - Weight and Power

C-Band FSS

Transponder

Antenna

Sub Total

WEIGHT(KG)

Low Risk High Risk

171.7

74.1

327.4 245.8

POWER(W)

Low Risk High Risk

1001

1001

708

708

Ku-Band FSS

Transponder

Antenna

Sub Total

625

187

812

362.4

160.6

523

1164

1164

785

785

Ka-Band FSS & Scan

FSS Transponder

SCAN Transponder

Baseband Proc.

Antenna

Sub-Total

751.4

636.0

355.0

264.5

516.3

447.6

297.4

230.4

3305

2180

1360

4

3043

1936

952

2

2006.9 1491.7 6849 5933

SCENARIO V TOTAL 3146.3 2260.5 9014 7426

5-143
ORIGINAL PAGE IS

OF POOR QUALITY

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5-144
Ford Aerospace &

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component level. Table, 5.'4 ..2-1. shows the projected antenna gain

and the power applifier power levels necessary to maintain the

required 36 dBW EIRP consistent with the WARC required power

2

flux density (PFD) of - 142.0 dBW/m for Region 2. The nine

beam coverage areas were developed in Section 4 to the SMS A

level and the covered SMSA's converted into lattitude and

longitude coordinates for development of the antenna. Appendix

1-2.2 contains the coordinates for each beam coverage area.

Table 5.4.2-1

Power Requirements For C-Band FSS. Scenario V

(Single Carrier Operation)

BEAM

1H

2V

3H

4V

EIRP=

PFD=

G (dB)

36.8

34.5

30.1

28.9

36.0 dBW

-142.0 dBW/m2

P (dBW)

0.7

3.0

7.4

8.6

P (W)

1.175

1.995

5.495

7.244

. Table 5.4.2-2 shows the estimated weight, power, and volume

for low risk (emerging) technology and high risk (projected)

technology for the transponder and antenna. Also included in

the estimates are the coax, waveguide, and harness interconnects, plus an estimate for integration hardware to put the

components together and provide necessary brackets for support

and mounting. This does not include any structure or satellite

mounting hardware, such as between the feed and reflector.

5.4.2.2 C-Band Antenna Subsystem

The C-Band FSS antenna subsystem provides transmission at 4

GHz and reception at 6 GHz of dual linear-polarized

communications signals. The purpose of the communication

antenna is to provide 4 beams to cover CONUS as shown in Figure

5.4.2-2. The orthogonal polarization is used for each

5-145
Table 5.4.2-2

ORIGINAL PAGE IS

OF POOR QUALTIY

Scenario V & VI - Pavload Summary

C-Band FSS

ORIGINAL PAGE K

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5-147
Ford Aerospace &

Communications Corporation

neighboring beams Table 5.4.2-3 presents the antenna subsystem

requirements.

Table 5.4.2-3

C-Band FSS Antenna Subsystem Requirements

Parameters Requirements

Frequency Transmit: 4 GHz band

Receive: 6 GHz band

Polarization Dual Linear

Coverage area 4 Beams cover

CONUS

Cross-pol 30 dB

Isolation

Co-pol

Isolation 27 dB

The antenna will consist of two overlapped. gridded

reflectors and two multihorn feed array systems, as depicted in

Figure 5.4.2-3. The grids of the reflector are selected to run

either in the horizontal or vertical direction for horizontal

or vertical polarization. They are used to help lower

cross-polarization energy that is produced by the field

curvature of an asymetric paraboloid. as well as the

cross-polarization radiated from the feed array. The

cross-polarization isolation achieved is greater than 30 dB.

In order to provide adequate sidelobe isolation between beams

for frequency reuse, the size of reflector should be 15'.

Figures 5.4.2-4 to 5.4.2-7 present the antenna radiation

pattern for each beam.

The predicted edge-of-coverage antenna gains are given in

Table 5.4.2-4.

5-148
Ford Aerospace'.&; .J,Wir}IHO

Communications,Cotporg|ion;,p

Figure 5.4.2-3 C-Band FSS Antenna Configuration

5-149
Ford Aerospace &

Communications Corporation

ORIGINAL PAGE IS

OF POOR QUALITY

Figure 5.4.2-4 C-Band FSS Northeast Spot Antenna Pattern

MflX.

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CONTOUR Dfltq

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fl

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-5.000

-6.000

-7.000

-10-000

-15.000

-20.000

-25.000

-30.000

-33.000

-35.000

(36.8 dBi.)

5-150
Ford Aerospace &

Communications Corporation

ORIGINAL PAGE IS

OF POOR QUALITY

Figure 5.4.2-5 C-Band FSS Northeast Antenna Pattern

MRX.

THETR

4.000

CONTOUR DflTfl

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fl

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0

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-7.GOO

-10-000

-1S-000

-20.000

-25-000

-30-000

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-35-000

(34.5 dBi.)

5-151
Ford Aerospace &• .•

Communications,Corporation; ',,£».

Figure 5.4.2-6 C-Band FSS Mideast Antenna Pattern

NfiX.

THETR

4.000

. c ^x\/x. \ ^» \\

CONTOUR DflTfl

SrriBOL LEVEL

R

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-4.000

-5.000

-6.000

-7.000

-10.000

-15-000

-20.000

-25.000

-30.000

-33.000

-35.000

(30.1 dBi.)

5-152
Ford Aerospace &

Communications Corporation

ORIGINAL PAGE IS

OF POOR QUALITY

Figure 5.4.2-7 C-Band FSS Western Antenna Pattern

MAX.

THETfl

4.0QQ

CONTOUR OflTQ

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-5.000

-6.000

-7.000

-10.000

-15.000

-20.000

-25.000

-30.000

-33.000

-35-000

(28.9 dBi.)

5-153
Ford Aerospace &

Communications Corporation

Table 5,4.2-4

C-Band FSS Predicted Antenna Gain

Coverage

(Beam No. )

1H

2V

3H

4V

Gain

(dBi

36.8

34.5

30.1

28.9

Diurnal and seasonal solar variations can cause temperature

extremes and gradients on the reflector surface, which, in

turn. mechanically distort the reflector and degrade the

electrical performance. Advanced Kevlar fiber composite

materials are used for the structural elements of the reflector

assembly to provide maximum thermal stability and structural

strength with minimum weight. Each reflector is a Kevlar/epoxy

laminate sandwich thin shell bonded in a backside or ring

reinforcing structure. The sandwich shell supports the gridded

system of wire. The largest existing dual gridded reflector

that has even been built is 72". The proposed size. 15' of

reflector aperture. presents challenging mechanical and

electrical design problems to provide the required mechanical

stiffness and strength using present state-of-art technology.

In addition, a 15' reflector is the maximum size that can be

accomodated in the space shuttle bay as an integral solid

reflector. Therefore, in order to stow the reflector in the

shuttle bay. it will have to be canted to achieve the

elliptical shape. An unfurable reflector is not practical,

even in 1994 technology, because of the thermal distortion,

manufactoring tolerances, and the distortion of the straight

grids on the reflector surface.

Table 5.4.2-5 summarizes the assessment of the critical

technology items for this subsystem.

5-154
Ford Aerospace &

Communications Corporation

Table 5.4.2-5

Assessment Of The Level Of Risk Of Critical Technology Items

Item Low Risk High Risk

Cross-Pol Isolation 27 dB 30 dB

Reflector Need development Slight

development

Weight

(Reflector) 70 kg 20% less

5.4.2.3 C-Band Transponder Subsystem. Fixed Satellite Service

The C-Band transponder subsystem consists of four

independent, 12 channel transponders, and hence has a total

capacity of 48 channels, each having a bandwidth of 36 MHz.

The four transponders utilize the same 500 MHz FSS band, having

an uplink at 6 GHz and a downlink at 4 GHz.

Each of the four 6 GHz inputs from.the antenna feed assembly

is filtered by an input preselector and then amplified and

downconverted to 4 GHz by the receiver. The 500 MHz IF band is

subdivided by an input multiplexer into twelve 36 MHz

channels. The filters of the input multiplexer also provide

the required narrow band receive filtering responses.

Twelve 4x4 switch matrices enable signals in any uplink

channel of one transponder to be connected to the same channel

in any of the other three transponders.

The channels are individually amplified by up to 8.5 watt

SSPAs. which contain one or more variable gain amplifiers. The

5-155
Ford Aerospace &

Communications Corporation

latter permit automatic accommodation of varying uplinK levels,

using an AGC loop, and SSPA back off via ground control. The

outputs of the SSPAs in each set of twelve channels are

combined in a twelve channel output multiplexer which also

provides the required narrow band transmit filtering

responses. The downlink signals are further filtered by

harmonic/bandpass filters prior to transmission from the

transmit antenna feed assembly. The transponder subsystem

features four for two receiver redundancy and five for four

SSPA redundancy.

5.4.2.3.1 6/4 GHz Receiver

See 5.2.2.3.1.

5.4.2.3.2 4GHz Input Multiplexer

See 5.2.2.3.2.

5.4.2.3.3 RF Switch Matrix

See 5.2.3.3.3.

5.4.2.3.4 4GHZ 8.5 watt SSPA

See 5.2.2.3.3.

5.4.2.3.5 4 GHz Output Multiplexer

See 5.2.2.3.4.

5.4.2.3.6 Pre-Select and Harmonic Filters

See 5.2.2.3.5.

5-156
Ford Aerospace &

Communications Corporation

5.4.3 Ka-Band FSS Pay-load

, it-. >/• *jy

This payload is identical to the Ka-Band FSS payload described

in Scenario II. See Section 5.2.3 for a detailed description.

5.4.4 Ka-Band Scan Payload

This payload is identical to the Ka-Band Scan payload described

in Scenario II. See Section 5.2.4 for a detailed description.

5.4.5 Ku-Band FSS Payload

5.4.5.1 Overview of Ku-Band FSS Payload

This payload triples the capacity of the current day Ku-band

payloads by using shaped beam technology. The system uses

horizontal and vertical linear polarization isolation for 2 times

reuse, and spatial isolation of shaped beams to achieve 9 times

reuse with respect to CONUS coverage. The beam coverages use

eight beams to cover CONUS and a ninth beam doubling the reuse in

the New York/New Jersey area of CONUS. The payload features a

dual gridded reflector assembly to obtain the polarization purity

required for the reuse. Each of the transponder channels is of

straight-forward design, and although electronic switches are

used for routing, it is only for traffic pattern changes, and

only used on a limited basis. It does, however, also provide the

flexibility to use the system as a SS-TDMA digital modulation

system if so desired. Figure 5.4.5-1 is a block diagram of the

Ku-Band FSS payload for Scenario V showing the breakdown to the

component level. Table 5.4.5-1 shows the projected antenna gain

and the power applifier power levels necessary to maintain the

required 39 dBW EIRP consistent with the WARC required power flux

density (PFD) of - 138.0 dBw/m for Region 2. The nine beam

coverage areas were developed in Section 4 to the SMSA level and

the covered SMSA's converted into lattitude and longitude

coordinates for development of the antenna. Appendix 1-1.2

contains the coordinates for each beam coverage area.

5-157
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5-158
Ford Aerospace &

Communications Corporation

Table 5.4.5-1

Power Requirements For Ku-Band FSS. Scenario V

(Single Carrier Operation)

EIRP=

PFD=

39.0 dBW

-138.0 dBW/ra2

Beam

1

2

3

4

5

6

7

8

9

G. dB

39.9

40.1

40.9

47.4

39.7

33.4

35.8

36.5

39.0

P. dBW

0.6

0.4

-0.4

-6,9

0.8

7.1

4.7

4.0

1.5

P. W

1.148

1.096

0.912

0.204

1.202

5.129

2.951

2.512

1.413

Table 5.4.5-2 shows the estimated weight, power, and volume

for low risk (emerging) technology and high risk (projected)

technology for the transponder and antenna. Also included in the

estimates are the coax, waveguide, and harness interconnects,

plus an estimate for integration hardware to put the components

together and provide necessary brackets for support and

mounting. This does not include any structure or satellite

mounting hardware, such as between the feed amd reflector.

5.4.5.2 Ku-Band FS Antenna Subsytem

The Ku-Band FSS antenna subsystem provides transmisssion at 11

GHz and reception at 14 GHz of dually linear-polarized communications signals. The purpose of the communication antenna is to

provide a beams to cover CONUS as shown in Figure 5.4.5-2. The

5-159
ORIGINAL PAGE IS

OF POOR QUALITY

Table 5.4.5-2

Scenario V. VI- A & B - Pavload Summary

Ku-Band FSS

ORIGINAL PAGE IS

Of POOR QUALfTY

ITEM

1

J

3

4

5

6

7

8

9

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rnMM r.nNTRfii » TNTFRFACF - ^•/>' '

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HARMQNTr FITTER

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5-161
Ford Aerospace &

Communications Corporation

combination of co-polarization and cross-polarization isolation

among these beams provides the required interbeam isolation for

this system. Table 5.4.5-3 summarizes the antenna subsystem

requirements.

Table 5.4,5-3

Ku-Band FSS Antenna Subsystem Requirements

Parameters Requirements

Frequency Transmit: 11 GHz Band

Receive: 14 GHz band

Polarization Dual Linear

Coverage area 9 Beams cover

CONUS

Cross-pol 30 dB

Isolation

Co-pol

Isolation 27 dB

The antenna will consist of two overlapped. gridded

reflectors and two multibeam feed array systems as depicted in

Figure 5.4.5-3. The grids of the reflector are selected to run

either in the horizontal or vertical direction for horizontal

or vertical polarization. They are used to help lower

cross-polarization energy that is produced by the field

curvature of the asymetric paraboloid, as well as the

cross-polarization radiated from the feed array. The

cross-polarization isolation achieved is greater than 30 dB.

In order to provide adequate sidelobe isolation between the

east and west half CONUS beams for frequency reuse, the size of

reflector should be 15'. Figures 5.4.5-4 to 5.4.5-4 to

5.4.5-12 present the antenna radiation patterns for the nine

beams.

5-162
Ford Aerospace &

Communications Corporation

Figure 5.4.5-3 Ku-Band FSS Antenna Configuration
Ford Aerospace &

Communications Corporation

Figure 5.4.5-4 Ku-Band FSS Beam IV Antenna Pattern

MfiX.

THETfl

4.0QQ

CONTOUR DPTfl

SYMBOL LEVEL

A Q.OOO

B -3.000 (39.9 dBi)

C -4.000

D -5.GOO

E -6.000

F -7.000

0 -10-000

H -15.000

1 -20.000

J -25-000

K -30.000

L -33.000

ft -35.000

BEflM IV

5-164
Ford Aerospace &

Communications Corporation

ORIGINAL PAGE IS

OF POOR QUALITY

Figure 5.4.5-5 Ku-Band FSS Beam 2V Antenna Pattern

MRX.

THETfl

4.0QQ

CONTOUR DflTfl

SYMBOL LEVEL BEflM 2V

q

8

C

0

E

F

0

H

I

J

K

L

M

0.000

-3.000

-4.000

-5.000

-6-000

-7.000

-10-000

-15.000

-20.000

-25.000

-30-000

-33.000

-35-000

(40.1 dBi)

5-165
Ford Aerospace &

Communications Corporation

 r'f

-..:'~~[-

Figure 5.4.5-6 Ku-Band FSS Beam 3V Antenna Pattern

MPX.

THETfl

4.000

CONTOUR DflTfl

SYMBOL LEVEL

fl Q.OOO

B -3.000 ( 40.9 dBi)

C -4.000

D -5.000

E -6.000

F -7.000

0 -10.000

H -15-000

1 -20.000

J -25.000

K -30-000

L -33.000

n -35.000

BERN 3V

5-166
Ford Aerospace &

Communications Corporation

ORIGINAL PAGE IS

OF POOR QUALITY

Figure 5.4.5-7 Ku-Band FSS Beam 4H Antenna Pattern

MRX.

THETfl

4.000

CONTOUR DflTfl

SYftBOL LEVEL

P 0.000

B -3-000 (47.4 dBi)

C -4.000

0 -5.000

E -6-000

F -7.000

0 -10.000

H -15.000

f -20.000

J -25.000

K -30.000

L -33.000

n -35.000

BEflM AH

5-167
Ford Aerospace;&{*^fj

'Communications. Corporation

• . -" ,.; ? '•"'• •'"'-! '*•'

Figure 5.4.5-8 Ku-Band FSS Beam 5H Antenna Pattern

MRX.

THETfl

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CONTOUR DflTfl

SYMBOL LEVEL

R O.QQO

B -3-000 (39.7 dBi)

C -4.000

0 -5.000

E ' -6-000

F -7.000

0 -10.000

H -15.000

1 -20.000

J -25.000

K -30-000

L -33.000

M -35-000

BEflM 5H

5-168
Ford Aerospace &

Communications Corporation

ORIGINAL PAGE IS

OF POOR QUALITY

Figure 5.4.5-9 Ku-Band FSS Beam 6H Antenna Pattern

.

THETR

4.000

CONTOUR DRTfl

SYnBOL LEVEL BERM 6H

fl

B

0

E

0

H

I

J

K

L

rt

Q.QQO

-3-000

-4.000

-5.000

-6-000

-7.000

-10.000

-15-000

-20.000

-25-000

-30-000

-33.000

-35-000

(33.4 dBi)

5-169
Communication s>Corporatiom

Figure 5.4.5-10 Ku-Band FSS Beam 7V Antenna Pattern

MAX.

THETfl

4.000

CONTOUR DflTP

SYMBOL LEVEL

BERN 7V

fl

B

C

0

E

F

a

H

I

J

K

L

M

a.QOO

-3-000

-4.000

-5.000

-6.000

-7.000

-10.000

-15.000

-20.000

-25-000

-30.000

-33.000

-35.000

(35.8 dBi)

5-170
Ford Aerospace &

Communications Corporation

ORIGINAL PAGE IS

OF POOR QUALITY

Figure 5.4.5-11 Ku-Band FSS Beam 8H Antenna Pattern

MAX.

THETR

4.000

CONTOUR OflTfl

SrflBOL LEVEL BEflM 8H

R

B

0

E.

F

0

H

I

J

K

L

M

0.000

-3 -000

-4.QOO

-6. GOD

-6.000

-7.000

-10.000

-16.000

-20.000

-25-000

-30.000

-33.000

-35.000

(36.5 dBi)

5-171
Ford Aerospace & ••• • •'• ' ;.-:&'

Communicatibns Corporation i -j. v

 j j» i . • < .;!J .'• ~\

Figure 5.4.5-12 Ku-Band FSS Beam 9H Antenna Pattern

MRX.

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SrMBOL LEVEL BEflM 9H

fl

B

C

0

E

F

G

H

r

j

K

L

fl

o.ooo

-3.000

-4.000

-s.ooo

-6.000

-7.000

-10.000

-15.000

-20.000

-25.000

-30.000

-33.000

-35.000

(39.0 dBi)

5-172
Ford Aerospace &

Communications Corporation

The predicted edge-of-coverage antenna gains are given in

Table 5.4.5-4.

Table 5.4.5-4

Ku-Band FSS Predicted Antenna Gain

Coverage GAin

Beam No. dBi

1 39.9

2 40.1

3 40.9

4 47.4

5 39.7

6 33.4

7 35.8

8 36.5

9 39

Diurnal and seasonal solar variations can cause temperature

extremes and gradients on the reflector surface, which, in

turn. mechanically distort the reflector and degrade the

electrical performance. Advanced Kevlar fiber composite

materials are used for the structural elements of the reflector

assembly to provide maximum thermal stability and structural

strength with minimum weight. Each reflector is a Kevlar/epoxy

laminate sandwich thin shell bonded in a backside or ring

reinforcing structure. The sandwich shell supports the gridded

system of wire. The largest existing dual gridded reflector

that has even been built is 72". The proposed size. 15' of

reflector aperture. presents a challenging mechanical and

electrical design problem to provide the required mechanical

stiffness and strength using present state-of-art technology.

In addition, a 15' reflector is the maximum size that can be

5-173
Ford Aerospace &

Communications Corporation

accomodated in the space shuttle bay with an integral solid

reflector. Therefore, in order to stow the reflector in the

shuttle bay, the reflector will have to be canted to achieve

the elliptical shape. An unfurlable reflector is not

practical, even in 1994 technology, because of the thermal

distortion, manufactoring tolerances, and the distortion of the

straight grids on the reflector surface.

\

Table 5.4.5-5 summarizes the assessment of the critical

technology items for this subsystem.

Table 5.4.5-5

Assessment Of The Level Of Risk Of Critical Technology Items

Item Low Risk High Risk

Cross-Pol isolation 27 dB

30 dB

Reflector Needs development Slight development

Weight

(Reflector) 70 kg 20% less

5.4.5.3 Ku-Band Transponder Subsystem, Fixed Satellite Service

The Ku-Band Transponder Subsystem consists of nine, 12

channel transponders, and hence has a total capacity of 108

channels. each having a bandwidth of 36 MHz. The nine

transponders utilize the same 500 MHz FSS band, having an

uplink at 14 GHz and downlink at 11 GHz. Each of the nine 14

Ghz inputs from the receive antenna beam forming network is

•

filtered by an input preselector, then amplified and down

converted to 11 GHz by the receiver. The receiver output is

fed to an input multiplexer which subdivides the 500 MHz IF

band into twelve. 36 MHz channels, while also providing the

required narrow band receive filtering responses.

5-174
Ford Aerospace &

Communications Corporation

The input multiplexers ace followed by twelve. 9x9 switch

matrices. The latter permit signals in any of the uplink

channels of a given transponder to be re-transmitted via any of

the other eight transponder output sections.

Each of the 108 channels is individually amplified by an

SSPA. which contains one or more variable gain amplifiers. The

latter permit automatic accomodation of varying uplink levels

using an AGC loop, and also up to 16 dB of power amp back-off

via ground control. For the Ku-band fixed satellite service,

from l watt to 5 watts are necessary to ensure adaguate EIRP.

If higher power EIRP is approved for Region 2. higher power

SSPA's could provide up to 20 watts, raising the EIRP by 6 dB

to 45 dBW

The outputs of the SSPAs in each set of twelve channels are

combined in an output multiplexer, which also provides the

required narrow band transmit filtering responses. The

downlink signals are further filtered by a harmonic/bandpass

filter prior to transmission from the antenna feed assembly.

The transponder subsystem features 4 for 2 redundancy for the

receivers, and 5 for 4 redundancy for the SSPAs.

5.4.5.3.1 14/11 GHz Receiver

See 5.2.5.3.1.

5.4.5.3.2 11 GHz Input Multiplexer

See 5.2.5.3.6.

5.4.5.3.3 RF Switch Matrix

See 5.2.3.3.3.

5.4.5.3.4 11 GHz Power Amplifiers

5-175
Ford Aerospace &

Communications Corporation

5.4.5.3.4.1 11 GHZ SSPA. 5 Watt

The 5 Watt. 11 GHz solid state power amplifier of low risk

technology uses gallium arsenide FETs as the active devices.

The output stage combines the output of three 2 watt FETs and

is driven by one 2 watt FET of the same type. This 2 watt

device has matching circuits incorporated within the device

package to match the FET chip to 50 ohms, thereby minimizing

amplifier tune and test time and maximizing the performance by

accomplishing the matching as closely as possible to the chip.

The three-way divider/combiner circuit is of the Wilkinson

type. Four stages of lower power gain precede the power

stages. Two of these low level stages use dual-gate FETs to

provide a variable gain which is set by the voltage' on the

second gate. The RF circuitry is etched in thin film metalization on alumina substrates which are bonded to moly or Kovar

carriers. The amplifier uses a .modular construction. Four

separate modules are individually tuned, tested. and then

integrated. Four interstate isolators are included to minimize

interaction between the modules when they are integrated. The

isolators are of the drop-in microstrip type to minimize size

and weight, except for the output isolator which is stripline

for lowest loss.

For high risk technology, rapid advances in gallium arsenide

technology and monolithic microwave integrated circuits (MMICs)

should make possible substantial improvements in size and

performance by 1994. Because of thermal considerations and the

need to maximize the efficiency, it is not expected that the

output stages will be in monolithic form. It is anticipated,

however, that 5 watts output power will be available from a

single device package with probably two FET chips, and matching

and combining circuitry integrated within the single package.

This will reduce the size by eliminating the need for the large

three-way divider/combiners. MMIC technology should make it

possible to integrate several stages of low power amplification

5-176
Ford Aerospace &

Communications Corporation

on a single chip. Similarly the VGA should be realizable on a

single chip. Thus, a 1994 5 watt amplifier could consist of

two low power gain chips, a driver amplifier in one device

package, and the output stage in a second package, leading to a

significant reduction in size and weight.

It is expected that commercial applications will lead the

device manufacturers to develop the packaged 5 watt device.

However, to obtain the required low power gain and variable

gain in a monolithic form, some non-recurring investment by

NASA or the user community will be required.

5.4.5.3.4.2 11 GHz SSPA 10 Watt

The 10 watt. 11 GHz solid state power amplifier of low risk

technology uses gallium arsenide FETs as the active devices.

The output stage combines the output of six 2-watt FETs. It

consists of two. 5 watt amplifiers with two-way divider/

combiners on the input and output. Each 5 watt amplifier

consists of three devices. 3-way Wilkinson divider/combiners,

and a driver stage. The 2 watt device has matching circuits

incorporated within the device package to match the FET chip to

50 ohms, thereby minimizing amplifier tune and test time and

maximizing the performance by accomplishing the matching as

closely as possible to the chip.

Four stages of lower power gain precede the power stage.

Two of these low level stages use dual-gate FETs to provide a

variable gain which is set by the voltage on the second gate.

The RF circuitry is etched in this film metalization on alumina

substrates which are bonded to moly or Kovar carriers. The

amplifiers use a modular construction. Four separate modules

are individually tuned and tested and then integrated. Four

interstage isolators are included to minimize interaction

between the modules when they are integrated. The isolators

5-177
Ford Aerospace &

Communications Corporation

are of the drop in microstrip type to minimize size and weight,

except for the output isolator which is stripline for lowest

loss.

For high risk technology, rapid advances in gallium arsenide

technology and monolithic microwave integrated circuits (MMICs)

should make possible substantial improvements in size and

performance by 1994. Because of thermal considerations and the

need to maximize the efficiency, it is not expected that the

output stages will be in monolithic form. It is anticipated,

however, that 5 watts of output power will be available from a

single device package with probably two FET chips, and matching

circuitry and combining circuitry integrated within the single

package. 10 watts will then be achievable by combining two of

these 5 watt devices by means of Wilkinson dividers. This will

reduce the size signficantly by eliminating the need for the

large three-way divider/combiners. MMIC technology should make

it possible to integrate several stages of low power

amplification on a single chip. Similarly, the VGA should be

realizable on a single chip. Thus, a 1994 10-watt amplifier

could consist of two low power gain chips, a driver amplifier

in one device package, and an output stage consisting of two 5

watt devices, leading to a significant reduction in size and

weight in comparison to the 1984 version.

We expect that commerical applications will lead the device

manufacturers to develop the packaged 5-watt device. However,

to obtain the required low power gain and variable gain in a

monolithic form, and to integrate all the devices into a space

qualified 10-watt SSPA. some non-recurring investment by NASA

or the user community will be required.

5.4.5.3.4.3 11 GHZ SSPA 10 Watt

The 20 watt. 11 GHz solid state power amplifier of low risk

technology uses gallium arsenide FETs as the active devices.

5-178
Ford Aerospace &

Communications Corporation

The output stage combines the output of twelve 2-watt FETs.

This can be accomplished in one of at least two ways. Two

six-FET stages, such as used in the 10-watt amplifier, can be

combined with two-way divider/combiners. This is relatively

straight forward, but combining twelve devices in this way is

bulky and inefficient. A better alternative is the use of a

twelve-way radial combiner. Two stages of gain will be

included in each of the twelve paths between the input divider

and output combiner so that the input divider can be driven .by

a single device. The 2-watt devices have matching circuits

incorporated within the device package to match the FET chip to

50 ohms, thereby minimizing amplifier tune and test time and

maximizing the performance by accomplishing the matching as

closely as possible to the chip.

Four stages of lower power gain precede the power stage.

Two of these low level stages use. dual-gate FETs to provide a

variable gain which is set by the .voltage on the second gate.

The RF circuitry is etched in thin film metalization on alumina

substrates which are bonded to moly or Kovar carriers. The

amplifiers use a modular construction. Four separate modules

are individually tuned and tested and then integrated. Four

interstage isolators are included to minimize interaction

between the modules when they are integrated. The isolators

are the drop in microstrip type to minimize size and weight,

except for the output isolator which is stripline for lowest

loss.

For high risk technology, rapid advances in gallium arsenide

technology and monolithic microwave integrated circuits (MMICs)

should make possible substantial improvements in size and

performance by 1994. Because of thermal considerations and the

need to maximize the efficiency, it is not expected that the

output stages will be in monolithic form. It is anticipated,

however, that 5 watts of output power will be available from a

single device package with probably two FET chips, and matching

5-179
Ford Aerospace &

Communications Corporation

circuitry and combining circuitry integrated within the single

package. 20 watts will then be achievable by combining four of

these 5-watt devices by means of Wilkinson dividers. This will

reduce the size significantly in comparison with the 12-way

divider/combiner and 12 gain stages. MMIC technology should

make it possible to integrate several stages of low power

amplification on a single chip. Similarly the VGA should be

realizable on a single chip. Thus, a 1994 20-watt amplifier

could consist of two low power gain chips, two driver stages

each using one packaged device, and an output stage consisting

of four 5-watt devices, leading to a significant reduction in

size and weight in comparison to the 1984 version.

It is expected that commercial applications will lead the

device manufacturers to develop the packaged 5-watt device.

However, to obtain the required low power gain and variable

gain in a monolithic form and to integrate all the devices into

a space qualified 20-watt SSPA. some non-recurring investment

by NASA or the user community will be required.

5.4.5.3.5 11 GHz Output Multiplexers

See 5.2.5.3.6.

5.4.5.3.6 Pre-Select and Harmonic Filters

See 5.2.2.3.5.

5-180
Ford Aerospace &

Communications Corporation

5.5 SCENARIO VI-A DEFINITION

5.5.1 Introduction

Scenario VI-A is the first of a complementary pair of

satellites designed to handle all of the WARC Region 2 Intelsat

traffic, intra Region 2 as well as AOR and FOR traffic, and

provide all domestic coverages for non-CONUS region 2 traffic.

This satellite is the easterly located satellite and handles the

primary processing of all of the Intelsat traffic except Canada.

The satellite also provides the high capacity CONUS FSS payloads

described in Scenario V. The Intelsat traffic is routed via the

baseband processor to an eastern or western ISL link. The

services provided are listed below:

o 48 Channels, 36 MHz. C-band CONUS FSS payload. 4 beams. 12

channels each. 4 x re-use.

o 108 channels 36 MHz. Ku-band. CONUS FSS payload. 9 beams.

12 channels each, 9 x re-use.

o 108 channels 36 MHz, C-band. International FSS payload. 9

beams. 12 channels each. 9 x re-use.

o 38 channels, 500 MHz. Ka-band, CONUS FSS payload. 20 beams,

approximately 2 channels each, 7.6 x re-use.

o 18 channels. 240 MHz. and 14 channels. 500 MHz. Ka-band.

CONUS FSS payload. 6 beams. CPS/thin route trunking. 4.6 x

re-use.

o C/L-band. Maritime payload. L to C-band - ship to shore; C

to L-band - shore to ship.

o Intersatellite link (ISL). 3 links 2 to the east and 1 to

the west, each 1.5 Gbps capacity.

5-181
Aerospace &

Communications Corporation

The C/L-band Maritime payload is the same as the second

generation Marisat that can handle 125 voice circuits. The

location of this scenario satellite is assumed to be 85 W for

o

antenna coverage. A location further east of 85 W would be

o

acceptable down to about 70 W.

An overview block diagram of the payload elements is shown in

Figure 5.5.1-1. Table 5.5.1-1 lists the major bus/payload

Table 5.5.1-1

Scenario VI-A - Payload Interface Requirements

o Mass 3200 kg

o Power Required

Sunlight

Eclipse

10.400 watts

75% min; 100% desired

o Pointing Requirement ± 0.05° absolute

(ie: RF boresight)

o Temperature Requirements

Antenna

Transponder

-900 to +110°C

-10°C to +59°C.

TWTA's +60°C

o Thermal Dissipation 1.5 kW in EPC's. 8 kW in

TWT's & 4 kW in feeds. & W/G

losses

o Lifetime 10 years without servicing

interface requirements, and Tables 5.5.1-2 and 5.5.1-3 present

the major antenna and transponder characteristics respectively.

The two Ka-Band antennae require individual gimbal systems for

5-182
ORIGINA

L PAGE IS

OF POOR QUALITY

Oo•HU(0C0)o

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5-183

(OCD

CDI
Ford Aerospace &

Communications Corporation

Table 5.5.1-2

Scenario VI-A Antenna Configuration

Antenna

System

Freq

(GHz) Reflector Polarization Feed Arrays

C-Band

FSS

4/6 15' (4.6m) dual

gridded reflector

Linear 2x26 feeds

plus

2x26 diplexers

Ku-Band 11/14 15'(4.6m)) dual

FSS gridded reflector

Linear 2x450

feeds.

Ka-Band 20/30 One solid 13'

FSS (4.0m) reflector

for tx. one

solid 9' (2.7m)

reflector for rec

(dual shaped

reflector each

with subreflector)

Linear Tx:500 feeds.

830 sws.

140 omj's;

same for

receive

C-Band

Int'1.

4/6 One 5m dual

gridded and 4m

dual gridded

Linear 2x92 feeds

plus

2x92 diplexers

C/L-Band

Maritime

1.5-1.7 One (3m) solid;

3.6-3.65 One (1.2m) solid

6.425- One (.76m) solid

6.441 reflectors

CP twelve 9.5"

feed arrays;

twelve 4.2"

feed arrays;

twelve 2.4"

feed arraya

GEO-GEO 60 GHZ One gimballed 3m

reflector for each

ISL. One east &

one west

CP Center fed

cassegrain

5-184
Ford Aerospace &

Communications Corporation

Table 5.5.1-3

Transponder Summary Scenario VI-A

Payload

HPA

U/L.D/L Number Channel RCVR Type HPA Type Power.

Freq. GHz Channels BW. RF (Number) Number W

C Band

FSS(CONUS)

6/4 48 36 6/4(8) SSPA(60)

Ku Band

FSS

(CONUS)

14/11 108 36 14/11(18) SSPA(135) 2

C-Band

FSS

(INTL)

6/4 108 36 6/4(18) SSPA(135) 4.5

Ka-band

FSS 30/20 38 500 30/4(40) TWTA(49) 75

Ka-band

Scan 30/20 32 240/500 30/4(12) TWTA(40) 75

C/L-band

Maritime

6/1.5

1.6/3.6

1

2

Total 35 6/1.5(2) SSPA(6)

Total 35 1/6/0.35 SSPA(2)

(2)

70

8.5

ISL 60/60 1.5 GHz 60/8(4) Impatt(6)

diode

5^185
Ford Aerospace &

Communications Corporation

steering- the two sub-reflectors to achieve ± 0.02 pointing of

the RF boresight. as well as the two ISL reflectors. The other

antennae will be rigidly mounted to the body and body steered via

the bus control system.

Due to the use of TWTA's for the Ka-band FSS payload, a 10-year

life is all that can be envisaged at this time because replacement of TWTA's at GEO. or return of the payload from GEO for

servicing and replacement of TWTA's. is not anticipated for the

early 2OOO time period. It is estimated that the identified

redundancy is compatible with a 10-year life application.

This scenario, as opposed to the prior scenarios, requires

in-orbit assembly and a modular approach to spacecraft assembly.

This may allow replacement of the Ka-band transponder package to

extend the life to fifteen or twenty years with GEO servicing.

If the spacecraft were designed to allow replacement of the

transponder package, it would probably require an added weight

penalty for the modularity. This scenario is clearly a launch

concept 2 scenario, and thus opens the possibility of the modular

approach.

Table 5.5.1-4 presents a summary of the high and low risk

weight and power for the individual payload elements in Scenario

VI-A.

In Appendix J. Tables 1 thru 8 show that all of the payload

elements have viable links with the various types of anticipated

modulation and access types. While some of the margins are low,

the links represent the worst case condition. If this scenario

were to be studied further for full system definition, link

margins could be improved for actual implementation.

5-186
Ford Aerospace &

Communications Corporation

Table 5.5.1-4

WEIGHT(KG)

Low Risk Hiqh Risk

C-Band FSS (Domestic)

Transponder

Antenna

Sub Total

Ku-Band FSS

Transponder

Antenna

Sub Total

Ka-Band FSS & Scan

FSS Transponder

SCAN Transponder

Baseband Proc.

Antenna

235

92.4

327.4

625

187

812

751.4

636.0

355.0

264.5

Sub-Total 2006.9

C-Band FSS( International

Transponder.

Itnl. Baseband Prcr.

Adi. CONUS Bsbd Prcr.

Antenna

Sub Total

Maritime

Transponder

Antenna

1

449.5

231

34.5

271.7

986.7

58.2

47

171.7

74.1

245.8

362.4

160.6

523

516.3

447.6

297.4

230.4

1491.7

301.9

193.3

28.8

225.5

749.5

39.9

39.2

POWER (W)

Low Risk Hiqh Risk

1001

1001

1164

1164

3305

2180

1360

4

6849

2319 .

649

172

*

3140

855

708

708

785

785

3043

1936

952

2

59.3_3_

1592

454

120

2166

649

Sub-Total 105.2 79.1 855 649

ISL'S 146.9 110.6 285 160

SCENARIO VI-A TOTAL 4385.1 3199.7 13294 10401

5-187
Ford Aerospace &

Communications Corporation

5.5.2 C-Band FSS Payload

The payload is identical to the C-Band FSS payload described

in Scenario V. See Section 5.4.2 for detailed description.

5.5.3 C/L Band Maritime Payload - Western Atlantic

5.5.3.1 Overview of C/L-Band Maritime Payload

This payload is the same as the second generation Inmarsat

transponders capable of handling 125 voice circuits. This

payload provides one-quarter of the worldwide coverage, with the

western satellite Scenario VI-B providing eastern Pacific

coverage, a European platform providing eastern Atlantic, and an

Asian platform providing western Pacific coverage. The less

than global coverage beam from each satellite will increase the

antenna gain slightly and result in improved performance. Also,

splitting the ocean regions in half will double the available

circuits for the ocean area. Figure 5.5.3-1 is a block diagram

of the Maritime payload for Scenario VI-A showing the breakdown

to the component level.

Table 5.5.3-1 shows the estimated weight, power, and volume

for low risk (emerging) technology and high risk (projected)

tech- nology for the transponder and antenna. Also included in

the estimates are the coax, waveguide. and harness

interconnects, plus an estimate for integration hardware to put

the components together and provide necessary brackets for

support and mount- ing. This does not include any structure or

satellite mounting hardware. such as between the feed and

reflector.

5-188
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5-189
ORIGINAL PAGE IS

OF POOR QUALITY

ASTERN ATLANTIC MARITIME C/L-BAND

Table 5.5.3-1

Scenario VI-A Pavload Summary

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5-190 Communications Corporation
ORIGINAL PAGE IS

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5-191
Ford Aerospace &

Communications Corporation

5.5.312 C/L-Band Maritime Antenna Subsystem

The C/t, Band Maritime Antenna Subsystem provides communications

at 1.5-1.7 GHz. 3.6-3.65 GHz. and 6.425-6.441 GHz bands. The

polarization is circular. The purpose of the antenna is to

provide a beam to cover the West Atlantic Region, as shown in

Figure 5,5.3-2.

The antenna will consist of 3 solid reflectors: a 3 meter

reflector for 1.6 GHz band; a 1.2 meter reflector for 3.6 GHz

band; and a 0.76 meter reflector for 6.4 GHz band, as shown in

Figure 5.5.3-3. Each reflector will be illuminated by 12 feeds.

A polarizer is employed at each feed to produce circular polarization. Figure 5.5.3-4 shows the beam layout to cover the West

Atlantic region. Figure 5.5.3-5 presents the antenna radiation

patterns. The edge-of-coverage gain is 18.5 dbi.

All technologies required in this system are well developed.

The level of risk of the technology items is low.

5.5.3.3 Maritime Transponder Subsystem

The Maritime transponder subsystem consists of two independent

transponders. The forward link is provided by a single channel

transponder with an uplink at C-Band and downlink at L-Band and a

channel bandwidth of 35 MHz. The 6.0 GHz input from the RHCP

antenna is filtered by the input preselector, then amplified and

downconverted to 1.5 GHz by the receiver. The receiver output is

narrow band filtered and then amplified by the L-Band high power

amplifier. Further filtering is provided by narrow-band bandpass

and harmonic rejection filters prior to downlink transmission via

the L-Band. RHCP antenna.

The return link is provided by a four channel, dual-conversion

transponder, having an L-Band uplink and C-Band downlink and a

total channel bandwidth of 35 MHz. The 1.6 GHz input from the

5-192
Ford Aerospace &

Communications Corporation

ia Figure 5.5.3-3 Scenario VI-A - Maritime

C/L Antenna Reflector

5-193
Ford Aerospace &

Communications Corporation

Figure 5.5.3-4 Maritime Beam Layout

ORIGINAL PAGE IS

OF POOR QUALITY

MRX.

THETfl

9.000

5-194
Ford Aerospace &

Communications Corporation

Figure 5.5.3-5 Maritime Antenna Pattern

CONTOUR DRTR

SYMBOL LEVEL

R

B

C

D

E

F

G

0.000

-3. 000 (18.2 dBi)

-5.000

-8.000

-10.000

-15.000

-20.000

5-195
Ford Aerospace &

Communications Corporation

LHCP antenna is filtered by the input preselector, then amplified

and downconverted to the 0.36 GHz intermediate frequency. The IF

output is split in a 4-way power divider, and narrow band filtering for the four channels is then provided by SAW filters. The

outputs of the SAW filters are combined in a summing amplifier

and then upconverted to 4.0 GHz. with final power amplification

being supplied by an 8 watt. C-Band SSPA. The downlink signals

are filtered by a harmonic/bandpass filter prior to transmission

from the LHCP transmit antenna.

5.5.3.3.1 Maritime C/L Receiver

Using low risk technology, this receiver provides for low noise

amplification at 6 GHz. It down converts 6 GHz to 1.5 GHz with a

Schottky diode mixer. The mixer is followed by bandpass filtering and amplification at 1.5 GHz. The local oscillator is a temperature-controlled crystal oscillator followed by a multiplier

chain.

Electrical Performance

Noise Figure 3.0 dB

Gain 70 dB

Output Power @ C/3IM=-40 dBc +13 dBm

Frequency Stability +1/-2 ppm

DC Power 8.0 watts

Mechanically, the receiver contains four subassembly trays: a

front end. a driver, a local oscillator, and a DC/DC converter.

The trays are assembled in a vertical stack. RF signal

connections between the front end. driver and local oscillator

trays are made with short loops of semirigid coaxial cable. A

selectable coaxial attenuator is included in the RF signal path

5-196
Ford Aerospace &

Communications Corporation

at the input to the driver to allow for adjustment of the overall

gain. Regulated DC voltages are supplied to the front end,

driver and local oscillator trays through a DC harness running

vertically along the side of the stack.

The microwave tray is an aluminum chassis that contains

.substrate assemblies that are bonded into the chassis, and substrate/carrier assemblies that are bolted in the chassis. The

substrate assemblies consist of MIC isolators, filters and

temperature compensation. The substrate/carrier assemblies are

MIC amplifiers. These amplifiers are constructed using hermetically packaged semiconductors, chip resistors, and chip capacitors on thin film alumina substrates. The bias circuits are

contructed using thick film alumina substrates, hermetically

packaged semiconductors, chip resistors and chip capacitors.

Mechanical Parameters

Mass 1.6 kg

Volume 175 cu in

Using high risk technology, the 6 GHz preamp would be updated

with the latest low noise GaAs FET. This will improve noise

figure from 3.0 dB to 1.5 dB. This mixer should be integrated

with the bandpass filtering. This will enhance the mixer

performance by improving gain flatness over temperature and

reducing test time. The 1.5 GHz amplifiers should be replaced by

monolithic gain blocks. These gain blocks are common to this

receiver and many other applications. This would reduce test

time and improve overall receiver performance. The crystal

oscillator chain could be replaced by a dielectric resonator

oscillator. The DRO will reduce complexity and cost. The

current receiver uses an analog circuit to temperature compensate

the receiver gain. Future receivers should use a digital system

to improve gain stability. The preamp. mixer/filter. DRO. and

5-197
Ford Aerospace &

Communications Corporation

digital temperature compensation require development that is

geared toward space qualification. The 1.5 GHz gain block would

be developed in the commercial market and could be

space-qualified. Power consump- tion will be reduced to 5.5

watts, primarily by the use of the DRO.

The use of monolithic gain blocks and dielectric oscilators

will reduce the size of the receiver. The number of

subassemblies can be reduced from 4 to 3. These would be a DC/DC

converter, front end/local oscillator, and driver.

Mechanical Parameters

Mass 0.5 kg

Volume 50 cu in

5.5.3.3.2 Maritime L-Band Power Amplifier

Using low risk technology, the 200 watt power amplifier could

readily be achieved with a 200 watt TWTA. An alternate approach

would be to utilize three 70 watt solid state amplifiers and

field combine the outputs via the multi-element feed network.

This approach is preferred to improve long term reliability.

The 70 watt power amplifier operates at 1550 MHz and has seven

amplification stages to provide a gain of 60 dB. The unit has

very good efficiency and adequate linearity to support

simultaneous 125-carrier operation. Bipolar transistors are used

for all RF stages except the two FET input stages. A number of

special design features are incorporated to protect the output

stage transistors, as well as enhance linearity, and permit

o

stable amplifier operation over a 66 C temperature range. The

two FET input stages are limiting multi-carrier envelope peaks at

a level of 4 dB above nominal input drive to prevent the output

stages from being overdriven. The input module also houses a

bipolar stage for gain-setting and temperature compensation. A

5-198
Ford Aerospace &

Communications Corporation

four-pole microstrip filter at the module output restricts the

operating bandwidth to 40 MHz. The second module has two medium

power class A bipolar stages which are followed by a 3 dB

Wilkinson splitter at the output. The following high power

section consists of two identical modules in parallel

configuration. Each module has an input and an output isolator,

and the two output signals are combined with a coaxial in-phase

power combiner. The active devices in the high power stages are

common base multi-cell transistors, derived from a standard class

C part and modified to enable more efficient linear operation.

Pre- biasing the power transistors results in a linear dynamic

range of better than 18 dB. The design of the bias network is

critical; it has to provide low source impedance and prevent

thermal runaway as well as maintain stability at very low

intermodulation frequencies. The four output stages in each

module have individual input/output matching circuits, and a

total of six 3 dB interdigital large couplers are used for power

splitting and combining. A similar single stage drives the four

output stages and is an integral part of the output modules. All

RF circuits use thin film metallization on alumina substrates.

Individual substrates are bonded to Kovar carriers, which are

bolted to the aluminum chassis to avoid expansion coefficient

differences. Bias networks are bonded to the bottom side of the

carriers. .This configuration and the use of feedthrough filters

yields very good RF/DC decoupling. All RF modules are tuned and

tested in the module chassis prior to amplifier integration. The

high power output modules have temporary by-pass circuits which

permit the optimization of individual stages prior to power

combining. The DC/DC converter is a separate module. It

supplies all required voltages and provides proper

turn-on/turn-off sequencing and filtering for the various

voltages.

Using high risk technology, the 200 watt power amplifier could

be a single solid state amplifier.

5-199
Ford Aerospace &

Communications Corporation

Bipolar solid stage technology at L-Band frequencies is very

refined at this point. State of the art multicell devices employ

emitter ballasting and stage metallization systems to achieve

high reliability factors. Internal matching to an intermediate

impedance level simplifies the complexity of external matching

circuits and yields wider bandwidth. It seems that demand will

double the present output power level of class A-B transistors to

about 30 watts in the near future. By 1994 a device with an

output power capability of 50 watts should be available. This

appears to be an ideal power level considering thermal size and

reliability aspects for a 200 watt amplifier design. Driver

stages below 1 watt output can be realized in MMIC technique.

This, in connection with the fewer number of required power

devices, should reduce the RF section footprint and size to onehalf of its present outline. Miniaturization has little impact

on the DC/DC converter module; its dimension and weight are

largely determined by magnetic circuits and large value

capacitors.

Special features such as limiting, temperature compensation

and gain setting would make the MMIC input module a custom device

that would require some NASA or customer funding to offset the

development costs.

5.5.3.3.3 Pre-Select. Harmonic and BP Filters

See 5.2.2.3.5.

5.5.3.3.4 Maritime L/UHF Receiver

Using low risk technology, this receiver provides for low

noise amplification at 1.6 GHz. It down converts 1.6 GHz to 360

GHz with a Schottky diode mixer. The mixer is followed by

bandpass filtering and amplification at 1.5 GHz. The local

oscillator is a temperature controlled crystal oscillator

followed by a multiplier chain. Filtering at 360 MHz is done by

dividing the

5-200
Ford Aerospace &

Communications Corporation

signal in a hybrid into 4 parts and filtering each part with a

saw filter. The 4 channels are then recombined and further

amplified in the 360 MHz driver amplifier.

Electrical Performance

Noise Figure . 2.5 dB

Gain 70 dB

Output Power @ C/3IM=-40dBc +13 dBm

Frequency Stability +1/-2 ppm

DC Power 8.5 watts

Mechanically, the receiver contains four subassembly trays: a

front end. a driver, a local oscillator and a DC/DC converter.

The trays are assembled in a vertical stack. RF signal

connections between the front end, driver and local oscillator

trays are made with short loops of semirigid coaxial cable. A

selectable coaxial attenuator is included in the RF signal path at

the input to the driver to allow for adjustment of the overall

gain. Regulated DC voltages are supplied to the front end. driver,

and local oscillator trays through a DC harness running vertically

along the side of the stack.

The microwave tray is an aluminum chassis that contains substrate

assemblies that are bonded into the chassis, and substrate/carrier

assemblies that are bolted in the chassis. The substrate

assemblies consist of MIC isolators. filters and temperature

compensation. The substrate/carrier assemblies are MIC

amplifiers. These amplifiers are constructed using hermetically

packaged semiconductors, chip resistors, and chip capacitors on

thin film alumina substrates. The bias circuits are constructed

using thick film alumina substrates. hermetically packaged

semiconductors, chip resistors and chip capacitors.

5-201
Ford Aerospace &

Communications Corporation

Mechanical Parameters

Mass 1.4 kg

Volume 175 cu in

Using high risk technology, the 6 GHz preamp would be updated

with the latest low noise GaAs FET. This will improve noise

figure from 2.5 dB to 1.5 dB. The mixer should be integrated

with the bandpass filtering. The will enhance the mixer

performance by improving gain flatness over temperature and

reducing test time. The 360 MHz amplifiers should be replaced by

monolithic gain blocks. These gain blocks are common to this

receiver and many other applications. This would reduce test

time and improve overall receiver performance. The crystal

oscillator chain could be replaced by a dielectric resonator

oscillator. The DRO will reduce complexity and cost. The

current receiver uses an analog circuit to temperature compensate

the receiver gain. Future receivers should use a digital system

to improve gain stability. The preamp. mixer/filter. DRO. and

digital temperature .compensation reguire development that is

geared toward space qualification. The 360 MHz gain block would

be developed in the commerical market and could be spacequalified. Power consumption will be reduced to 7.0 watts,

primarily by the use of the DRO.

The use of monolithic gain blocks and dielectric oscillators

would reduce the size of the receiver. The number of subassemblies can be reduced from 4 to 3. These would be a DC/DC

converter, front end/local oscilator. and driver.

Mechanical Parameters

Mass 0.5 kg

Volume 40 cu in

5-202
Ford Aerospace &

Communications Corporation

5.5.3.3.5 Maritime UHF/4 GHz Upconverter

Using low risk technology, this reciever provides for low

noise amplification at 360 MHz with a 3 stage amplifier and

upconverts to 4 GHz with a Schottky diode mixer. The mixer is

followed by bandpass filtering. The local oscillator is a

temperature controlled crystal oscillator followed by a

multiplier chain.

Electrical Performance

Gain 70 dB

Output Power @ C/3IM=-40dBc -10 dBra

Frequency Stability +1/-2 ppra

DC Power 7.5 watts

Mechanically, the receiver contains four subassembly trays: a

front end. a driver, a local oscillator, and a DC/DC converter.

The trays are assembled in a vertical stack. RF signal

connections between the front end. driver and local oscillator

trays are made with short loops of semirigid coaxial cable.

Regulated DC voltages are supplied to the front end. driver and

local oscillator trays through a DC harness running vertically

along the side of the. stack.

The microwave tray is an aluminum chassis that contains

substrate assemblies that are bonded into the chassis and

substrate/carrier assemblies that are bolted in the chassis. The

substrate assemblies consist of MIC isolators, filters and

temperature compensation. The substrate/carrier assemblies are

MIC amplifiers. These amplifiers are constructed using

hermetically packaged semiconductors, chip- resistors, and chip

capacitors on thin film alumina substrates. The bias circuits

5-203
Ford Aerospace &

Communications Corporation

are contructed using thick film alumina substrates,

hermetically packaged semiconductors, chip resistors and chip

capacitors.

Mechanical Parameters

Mass 1.2 kg

Volume 100 cu in

Using high risk technology, the 360 MHz preamp will be updated

by replacing it with a monolithic amplifier. The mixer will be

integrated with bandpass filtering. This will enhance the mixer

performance by improving gain flatness over temperature and

reducing test time. The crystal oscillator will be replaced by a

dielectirc resonator oscillator. The DRO will reduce complexity

and cost. The current upconverter uses an analog circuit to

temperature compensate upconverter gain. Future upconverters

should use a digital system to improve gain stability. The DRO

and digital temperature compensation require development that is

geared toward space qualification. The power consumption will be

reduced to 5.0 watts primarily by the use of the DRO.

The use of dielectric oscillators will reduce the size of the

upconverter. The number of subassemblies can be reduced from 3

to 2. These would • be a DC/DC converter. front end/local

oscillator.

Mechanical Parameters

Mass 0.3 kg

Volume 20 cu in

5.5.3.3.6 C-Band Power Amplifier

See 5.2.2.3.3.

5-204
Ford Aerospace &

Communications Corporation

5.5.4 C-Band FSS International Payload

'& zti&t jrt;.'ij.,,Y.-vi>

. YTUAUO 8OOC« ^

5.5.4.1 Overview of C-Band FSS International Payload

The payload provides a nine tiroes re-use of the 500 MHz C-Band

bandwidth and handles all of the projected Intelsat traffic south

of the Mexican border. The traffic is processed on board and

routed to either an eastern or western-directed ISL or to the

U.S.. or back to south-of-the-border for intra-Region 2 traffic.

The re-use is achieved through nine shaped beams by spatial and

polarization isolation. A unique feature of this payload is that

the baseband processor accepts FDMA/FDM/FM uplink signal and

performs an analog to digital conversion on board to route the

signals, and also performs a digital to analog conversion on the

downlink so the receiving station maintains its analog

characteristics. The switch network and baseband processing

would also accept digital modulation techniques, thus allowing SS

TDMA operation if so desired. Figure 5.5.4-1 is a block diagram

of the C-Band FSS international payload for Scenario VI-A,

showing the breakdown to the component level.

Table 5.5.4-1 shows the estimated weight, power, and volume for

low risk (emerging) technology and high risk (projected)

technology for the transponder and antenna. Also included in the

estimates are the coax, waveguide, and harness interconnects,

plus an estimate for integration hardware to put the components

together and provide necessary brackets for support and

mounting. This does not include any structure or satellite

mounting hardware, such as between the feed and reflector.

5.5.4.2 C-Band FSS International Antenna Subsystem

The C-Band International Antenna Subsystem provides - the

transmission at 4 GHz and reception at 6 GHz of dually linearpolarized communications signals. The purpose of the

communication antenna is to provide multiple beams to cover

5-205
ORIGINAL PAGE IS

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Scenario VI-A - Pavload Sumtnacv

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5-207 ~2_ FQLDOUT FRAME

Ford Aerospace &

Communications Corporation
Ford Aerospace &

Communications Corporation

portions of Central and South America, and the Caribbean, as

depicted in Figure 5.5.4-2. The combination of co-polarization

and cross- polarization isolation among these beams provides the

required interbeam isolation for the system. Table 5.5.4-2

summarizes the antenna subsystem requirements.

Table 5.5.4-2

C-Band International Antenna Subsystem Requirements

Parameters Requirements

Frequency Transmit: 4 GHz band

Receive: 6 GHz band

Polarization Dual Linear

Coverage area South/Central America

Co-polarization 27 dB

isolation

Cross-Polarization 30 dB

Isolation

The antenna will consist of two dual-gridded reflectors, one 5

meters and the other 4 meters, as shown in Figures 5.5.4-3 and

5.5.4-4. The 5 meter reflector is used for Central America and

the 4 meter, for South America. Normally, a single large

reflector is preferred for generating a shaped beam. However, a

larger size aperture radiates a narrower constituent beam so that

the required scanning range in terras of beamwidths is therefore

larger. This results in a more severe phase aberration for the

edge beams. Theoretically, the phase aberration can be corrected

by using an infinitely size of the feed array. However, such an

approach is not practical. The use of a two reflector antenna

system increases the beamwidth of the constituent beam and hence

reduces the phase aberration for the edge beam. Figures 5.5.4-5

to 5.5.4-13 present the antenna radiation patterns. Table

5-208
Ford Aerospace &

Communications Corporation

Figure 5.5.4-2 C-Band International Antenna

Coverage Requirements

5-209
Ford Aerospace &

Communications Corporation

Figure 5.5.4-3 5-Meter Antenna Configuration

7. 4-0%

5-210
Ford Aerospace &

Communications Corporation

5-211
Ford Aerospace &

Communications Corporation

ORIGINAL PAGE BS

OF POOR QUALrTY

Figure 5.5.4-5 C-Band International Beam 1H Antenna Pattern

CONTOU R DflTH

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5-212
Ford Aerospace &

Communications Corporation

Figure 5.5.4-6 C-Band International Beam 2V Antenna Pattern

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5-213
Ford Aerospace &

Communications Corporation

ORIGINAL PAGE IS

OF POOR QUALITY

Figure 5.5.4-7 C-Band International Beam 3H Antenna Pattern

CONTOUR DflTfl

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Aerospace & . .<- • .•'".' • . '•

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Figure 5.5.4-8 C-Band International Beam 4V Antenna Pattern

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5-215
Ford Aerospace &

Communications Corporation

Figure 5.5.4-9 C-Band International Beam 5H Antenna Pattern

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5-216
Ford Aerospace &

Communications Corporation

Figure 5.5.4-10 C-Band International Beam 6V Antenna Pattern

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5-217
Ford Aerospace &

Communications Corporation

ORIGINAL PAGE IS

OF POOR QUALITY

Figure 5.5.4-11 C-Band International Beam 7V Antenna Pattern

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Figure 5.5.4-12 C-Band International Beam 8H Antenna Pattern

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5-219
Ford Aerospace &

Communications Corporation

Figure 5.5.4-13 C-Band International Beam 9H Antenna Pattern

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5-220
Ford Aerospace &

Communications Corporation

5.5.4-3 summarizes the edge-of-coverage antenna gain for each

beam.

Table 5.5.4-3

C-Band International Predicted Antenna Gain

Coverage Area Gain (dBi)

1H 35.6

2V 39.4

3H 35.1

4V 40.0

5H 40.0

6V 35.1

7V 33.6

8H 33.6

9H . 35.1

Each reflector/array system operates in both the transmit

and receive bands. The grids of the reflector are selected to

run either in the horizontal or vertical direction for

horizontal or vertical polarization. They are used to help

lower cross-polarization energy that is produced by the field

curvature of the asymmetric paraboloid, as well as the

cross-polarization radiated from the feed array. The

cross-polarization isolation achieved is greater than 30 dB.

Diurnal and seasonal solar variations can cause temperature

extremes and gradients on the reflector surface, which, in

turn, can mechanically distort the reflector and degrade the

electrical performance. Advanced kevlar fiber composite

materials are used for the structural elements of the reflector

assembly to provide maximum thermal stability and structural

strength with minimum weight. Each reflector is a kevlar/epoxy

laminate sandwich, thin-shell bonded to a backside or ring

reinforcing structure. The sandwich shell supports the gridded

system of wire. The largest existing dual-gridded reflector

5-221
Ford Aerospace &

Communications Corporation

that has ever been built is 72". The current size. 5 meters,

presents a challenging mechanical and electrical design problem

to the present state-of-the-art. In addition, a 5 meter

reflector exceeds the maximum size that can be accomodated on

the space shuttle bay with an integral solid reflector.

Therefore, the edge of the reflector may be folded. The

cross-polarization purity may be degraded due to the

intermediate structure of the folded reflector. An unfurlable

reflector is not practical, even in the 1994 technology,

because of the thermal distortion, manufacturing RMS, and the

distorted straight grids on the reflector surface. Table

5.5.4-4 summarizes the assessment of the critical technology

items for this subsystem.

Table 5.5.4-4

Assessment Level of Risk of Critical Technology Items

Item Low Risk High Risk

Cross-polarization

isolation 27 dB 30 dB

Co-polarization 25 dB 27 dB

isolation'

Reflector Needs Needs

Development Development

Weight

(Reflector) 191 kg 20% less

5,5.4.3 C-Band Transponder Subsystem International Service

The C-Band transponder subsystem consists of nine semiindependent. 12 channel transponders, and hence has a total

capacity of 108 channels, each having a bandwidth of 36 MHz.

The nine transponders utilize the same 500 MHz FSS band, having

5-222
Ford Aerospace &

Communications Corporation

an uplink at 6 GHz and a downlink at 4 GHz. The transponders

also interconnect with the east and west ISL's and the Ka-Band

CONUS and scan beams via switch matrix.

Each of the nine 6 GHz inputs from the antenna feed assembly

is filtered by an input preselector and then amplified and down

converted to 4 GHz by the receiver. The 500 MHz IF band is

subdivided by an input multiplexer into twelve 36 MHz

channels. The filters of the input multiplexer also provide

the required narrow band receive filtering responses.

Twelve switch matrices enable signals in any uplink channels

of one transponder to be connected to the same channel in any

of the other eight international transponders, or with the east

and west ISLs and the Ka-Band transponders.

The channels are individually amplified by up to 5 watt

SSPA's which contain one or more variable gain amplifiers. The

latter permit automatic accommodation of varying uplink levels

using an AGC loop, and SSPA back off via ground control. The

output of the SSPA's in each set of twelve channels are

combined in a twelve channel output multiplexer, which also

supplies the required narrow band transmit filtering

responses. The downlink signals are further filtered by

harmonic/bandpass filtering prior to transmission from the

transmit antenna feed assembly. The transponder subsystem

features four for two receiver redundancy and five for four

SSPA redundancy.

5.5.4.3.1 6/4 GHz Receiver

See 5.2.2.3.1.

5.5.4.3.2 4 GHz Input Multiplexer

See 5.2.2.3.2.

5-223
Ford Aerospace &

Communications Corporation

5.5.4.3.3. RF Switch Matrix

See 5.2.3.3.3.

5.5.4.3.4 4 GHZ 8.5 Watt SSPA

See 5.2.2.3.3.

5.5.4.3.5 4 GHz Output Multiplexer

See 5.2.2.3.4.

5.5.4.3.6 Pre-Select and Harmonic Filter

See 5.2.2.3.5.

5.5.4.4 Baseband Processor

A new concept in on-board processing was developed for use

in Scenario VI-A. the use of A/D and D/A conversion. Section

4.6.4.5 describes the rationale for providing this capability.

Figure 5.5.4-14 shows the uplink processing performed on the

channels carrying international/regional traffic for the Latin

America/Caribbean coverage. Each 36 MHz channel consists of

several FDMA subchannels (see Figure 4.6-4). Each subchannel

is filtered (FDM demux) and connected to a digital signal at a

rate dependent on the size of the subchannel. The digital

signals are then TDM multiplexed into 750 Mb/s streams and

routed to a digital routing switch, which operates in a fashion

similar to the Ka-band BBP. In fact, this VI-A routing switch

interface with the Ka-band BBP to carry U.S.

international/regional traffic; the ISLs are also routed via

this switch (see Figure 5.5.4-15). For the downlink, the

reverse process is required, as shown in Figure 5.5.4-16.

5-224
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Because this concept is new. there.are several factors which

should be analyzed in more detail to ensure feasibility of the

design.

a) Bandwidth

As previously noted, it would be desirable to break the 36

MHz transponder band into more than one access size so that

traffic bundles of different sizes can be carried as

efficiently as possible. In addition, it may be possible to

make the division of bandwidth flexible through the use of

switched filters, or by means of programmable digital

filtering. The bandwidths selected would in turn determine

the sampling rate for each access size.

b) Bits per Sample

Standard encoding used in telephony uses 8 bits per

sample. A/D converters ranging from 6 to 9 bits resolution

are currently available. The greater the number of bits,

the better the quality (lower quantization noise); however,

the price of this quality is additional requirements for

buffers for the same throughput.

c) Buffer Requirements

The total buffer requirements depend on the bits per

sample, frame length, and total amount of traffic requiring

A/D and D/A processing. Only a relatively small proportion

of the traffic on a satellite will require such processing.

d) Control Requirements

The output of .an A/D converter is a continuous bit

stream. The on-board processing must accomplish the

necessary framing, synchronization, and high speed bursting

5-228
Ford Aerospace &

Communications Corporation

On-board switching of digital signals can be done either by

means of SS/TDMA or baseband processing techniques. The

latter is the most flexible approach, but would probably

require more mass and power. On the other hand. SS/TDMA

switching is performed at IF with very high burst rates.

This aspect of the architecture will need to carefully

analyzed to ensure functional compatibility.

f) Filtering

In oxder to separate the accesses within a transponder or

channel, some form of filtering or demultiplexing (combining

or multiplexing at the payload output) of the demodulated

signal is required. This could be done, either before or

after A/D conversion. The approach described previously

performs the filtering first.

Several factors would have to be considered to ensured the

proposed system meets applicable CCITT or AT&T standards.

Noise introduced by the A/D and D/A conversions can be affected

by the encoding algorithm used. (PCM. Delta-Mod etc.). the

sampling rate, and the number of bits per sample. On the

analog side, one should evaluate such items as dynamic range,

whether low speed data is to be supported, and whether

companding is used.

The approach selected should meet end-to-end performance

standards. This will require allocation of performance to the

uplink, downlink, ISL (if used), and the on-board processing.

For low risk technology, the ACTS BBP weight, power, and

volume and engineering estimates are the basis of the

estimate. For the high risk technology, it is assumed that

additional VLSI development and advances in speed and power

would yield lighter weight, lower power and correspondingly

lower volume. This is an area where the custom VLSI work would

5-229
Ford Aerospace &

Communications Corporation

not likely be done without NASA/government subsidized effort

such as the ACTS processor and the various NASA LeRC technology

development programs.

5.5.5 Ka-Band FSS Pavload

This payload is identical to the Ka-Band FSS payload

described in Scenario II. See 5.2.3 for detailed description.

5.5.6 Ka-Band Scan Payload

The payload is identical to the Ka-Band Scan payload

described in Scenario II. See 5.2.4 for detailed description.

5.5.7 Ku-Band FSS Payload

This payload is identical to the Ku-Band FSS payload

descrived in Scenario V. See 5.4.5 for detailed description

5.5.8 60 GHz Inter-Satellite Link (ISL)

The cross link between two geosynchronous satellites with up

to 160 degrees of separation (83,000 km) is capable of

simultaneous transmission and reception of 1.5 Gbps data

through staggered quadrature phase shift keying (SQPSK)

modulation using a 5 watt IMPATT diode stable amplifier and a

gimbal mounted, 3.0 m parabolic dish Cassegrain antenna with

low loss beam waveguide. The communication capability is

maintained year round except for the brief periods (less than

0.01% per year total) when the sun is in conjunction with the

antenna field of view. During these brief periods, the link is

maintained at 300 Mbps. Automated acquisition/reacquisition

and monopulse tracking are maintained at all times regardless

of sun effect.

5-230
Ford Aerospace &

Communications Corporation

A microprocessor controlled automated main beam acquisition

algorithm receiver with monopulse tracking is capable of

initiating and accomplishing link acquisition at any

contactable time regardless of the effect of sun. With this

design, high confidence acquisition can be accomplished having

an initial attitude plus pointing error as large as +.2.0

degrees.

To accomodate a conglomerate of up to 4.5 Gbps traffic from

all links per each satellite requires innovative frequency and

polarization planning. In addition, key inter/intra system

interference analyses would have to be conducted to ensure

adherence to the WARC1 79 frequency allocation for the 60 GHz

band.

The links on Scenario VI-A would require two 1.5 Gbps links

on the eastern ISL and one 1.5 Gbps on the western ISL. Figure

5.5.8-1 is a block diagram of the single link ISL for Scenario

VI-A showing the breakdown to the component level. Table

5.5.8-1 shows the estimated weight, power, and volume for low

risk (emerging) technology and high risk (projected) technology

for the transponder and antenna. Also included in the

estimates are the coax, waveguide, and harness interconnects^

plus an estimate for integration hardware to put the components

together and provide necessary brackets for support and

mounting. This does not include any structure or satellite

mounting hardware such as between the feed and reflector.

5-231
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5-232
ORIGINAL PAGE IS

OF POOR QUALITY

Table 5.5.8-1

Scenario VI_A P^yioad Summary

ORIGINAL PAGE IS

OF POOR QUALITY

LOW RISK TECHNOLOGY

MSMITTER(5W. IMPATT)

5-23 3 FQLDOUT FJJAME

Z FQLDOUT

Ford Aerospace &

Communications Corporation
Ford Aerospace &

Communications Corporation

5.6 SCENARIO VI-B DEFINITION

5.6.1 Introduction

Scenario VI-B is the second of a complementary pair of

satellites designed to handle all of the WARC Region 2 Intelsat

traffic, intra-Region 2 traffic AOR and FOR traffic and provide

all domestic coverages for non-CONUS Region 2 traffic. This

satellite is the westerly located satellite and handles the

primary processing of Canadian Intelsat traffic and the

domestic non-CONUS traffic for Region 2. The satellite also

provides the high capacity CONUS FSS payloads described in

Scenario V, except the C-Band CONUS which could not be isolated

from the Mexican and Canadian domestic service. The Intelsat

traffic is routed via the baseband processor to an eastern or

western ISL link. The services provided are listed below:

o 38 Channels, 36 MHz. Ku-band non CONUS payload 4 beams.

3.2 x re-use

o 108 channels 36 MHz, C-band. Non-CONUS FSS. 9 beams, 12

channels each. 9 x re-use.

o 108 channels. 36 MHz. Ku-band. CONUS payload. 9 beams, 12

channels each. 9x re-use.

o 38 channels. 500 MHz. Ka-Band. CONUS FSS. 20 beams. 7.6 x

re-use.

o 18 channels, 240 MHz, and 14 channels. 500 MHz. Ka-band,

CONUS FSS payload. 6 beams. CPS/thin route trunking. 4.6 x

re-use.

o C/L-band, Maritime payload, L to C-band - ship to shore; C

to L-band - shore to ship.

o Intersatellite link (ISL), 3 links 2 to the east and 1 to

the west, each 1.5 Gbps capacity.

234
Ford Aerospace &

Communications Corporation

The C/L-band Maritime payload is the same as the second

generation Marisat that can handle 125 voice circuits. The

location of this scenario satelite is assumed to be 101 W for

antenna coverage and location further west of 101 W would be

o

acceptable down to about 110 W.

An overview block diagram of the payload elements is shown in

Figure 5.6.1-1. Table 5.6.1-1 lists the major bus/payload

interface requirements, and Tables 5.6.1-2 and 5.6.1-3 present

the major antenna and transponder characteristics respectively. The two Ka-Band antennae require individual gimbal

o

systems for steering the two sub-reflectors to achieve +0.02

pointing of the RF boresight. as well as the two ISL reflectors.

The other antennae will be rigidly mounted to the body and body

steered via the bus control system.

Table 5.6.1-1

Scenario VI-B - Payload Summary

o Mass 2926 kg

o Power Required

Sunlight 11.200 watts

Eclipse 75% min; 100% desired

o Pointing Requirement +.0.05° absolute (ie: RF

boresight)

o Temperature Requirements

Antenna -90° to +110OC

Transponder -IQOC to +59QC. TWTA's +60QC

o Thermal Dissipation 1.5 kW in EPC's. 8 kW in TWT's &

4 kW in feeds & W/G losses

o Lifetime 10 years without servicing

5-235
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5-236
Ford Aerospace &

Communications Corporation

Antenna

System

Table 5.6.1-2

Scenario VI-B Antenna Configuration

Freq

(GHz) Reflector Polarization Feed Arrays

C-Band

FSS

(Non-CONUS)

Ku-Band

FSS

(CONUS &

Can.& Mex)

Ka-Band

FSS

Ku-Band

(Brazil)

C/L-Band

Maritime

GEO-GEO

4/6 9m unfurlable

reflector

11/14 15'(4.6m)) dual

gridded

reflector

20/30 One solid 13'

(4.0m) reflector for tx. one

solid 9'(2.7m.)

reflector for rec

(dual shaped

reflector each

with subreflector)

11/14 1m dual gridded

reflector

1.5-1.7 one(1.2m)solid;

3.6-3.65 one(0.5m) solid

6.425- one(0.35m) solid

6.441 reflectors

60 GHz One gimballed 3m

reflector for each

ISL. One east &

one west

CP

Linear

Linear

Linear

CP

CP

400 feeds

plus

400 diplexers

2x450+350

feeds.

Tx:500

feeds,

830 sws.

140 oraj's;

same for

Rec.

2x14 Feeds

Center fed

cassegrain

Due to the use of TWTA's for the Ka-band FSS payload. a 10-year

life is all that can be envisaged at this time as replacement of

TWTA's is not anticipated for the early year 2000 time period. It

is estimated that the identified redundancy is compatible with a

10 year life application.

This scenario in similiar to VI-A in that it requires in-orbit

assembly and a modular approach to spacecraft assembly. This may

allow replacement of the Ka-band transponder package to extend the

5-237
Ford Aerospace &

Communications Corporation

life to fifteen or twenty years with GEO servicing. If the

spacecraft were designed to allow replacement of the transponder

package it would probably require an added weight penalty for the

modularity. This scenario is clearly a launch concept 2 scenario

and thus open the possibility of the modular approach.

Table 5.6.1-4 presents a summary of the high and low risk

weight and power for the individual payload elements in Scenario

VI-B.

Table 5.6.1-3

Transponder Summary Scenario VI-B

U/L.D/L Number Channel RCVR Type HPA Type HPA

Payload Freq. GHz Channels BW. R/F (Number) (Number) Power.W

Ku Band

FSS

(Non-CONUS)

14/11

ISL 60/60

38

Ku-Band

FSS

(CONUS)

Ka-Band

FSS

Ka-Band

Scan

C/L-Band

Maritime

14/11

30/20

30/20

6/1.5

1.6/3.6

108

38

32

1

2

36

36

500

14/4(6) SSPA(60) 5.0

11/14(18) SSPA(135) 2

30/4(40) TWTA(49) 75

240/500 30/4(12) TWTA(40) 75

Total 35 6/1.5(2) SSPA(6) 70

Total 35 1/6/0.35 SSPA(2) 8.5

(2)

1.5 GHZ 60/8(2) Impatt 5

diode (4)

In Appendix K, Tables 1 thru 20 show that all of the payload

elements have viable links with the various types of anticipated

modulation and access types. While some of the margins are low.

5-238
Ford Aerospace &

Communications Corporation

Table 5.6.1-4

Scenario VI-B Weight and Power Summary

WEIGHT(KG) POWER(W)

Low Risk High Risk Low Risk High Risk

Ku-Band FSS (CONUS)

Transponder

Antenna

Sub Total

625

187

812

362.4

160.6

523

1164

1164

785

785

Ka-Band FSS+Scan (CONUS)

FSS Transponder

SCAN Transponder

Baseband Processor

Antenna

Sub Total

751.4

636.0

355.0

264.5

516.3

447.6

297.4

230.4

3305

2180

1360

4

3043

1936

952

2

2006.9 1491.7 6849 5933

C-Band FSS (NON-CONUS)

Transponder 461.1

Baseband Processor 163.4

Antenna . 121

s

Sub Total 745.5

334.3

136.9

103

574.2

2231

473

2704

1573

330

1903

Ku-Band FSS (NON CONUS)

Transponder 224.9

Antenna 75.9

Sub Total 300.8

123.9

62.5

186.4

2751

2751

1796

1796

Maritime

Transponder

Antenna

Sub-Total

58.2

5.0

63.2

39.9

4.2

44.1

855

855

649

649

ISL'S 139.7 106.6 224 131

SCENARIO VI-B TOTAL 4068.1 2926 14547 11197

5-239
Ford Aerospace &

Communications Corporation

the links represent the worst case condition. If this scenario

were to be studied further for full system definition it is

expected that the link margin could be improved.

5.6.2 C/L Band Maritime Payload - Eastern Pacific

5.6.2.1 Overview of C/L-Band Maritime Payload

This payload is the same as the second generation Inmarsat

transponders capable of handling 125 voice circuits. This

payload provides one-quarter of the worldwide coverage with the

eastern satellite, scenario VI-A. providing western Atlantic

coverage and a European platform providing eastern Atlantic and

on Asian platform providing western Pacific coverage. The less

than global coverage beam from each satellite will increase the

antenna gain slightly and result in improved performance.

Also,splitting the ocean regions in half will double the

available circuits for the ocean area. Figure 5.6.2-1 is a block

diagram of the Maritime payload for Scenario VI-B showing the

breakdown to the component level.

Table 5.6.2-1 shows the estimated weight, power, and volume for

low risk (emerging) technology and high risk (projected) technology for the transponder and antenna. Also included in the

estimates are the coax, waveguide, and harness interconnects,

plus an estimate for integration hardware to put the components

together and provide necessary brackets for support and

mounting. This does not include any structure or satellite

mounting hardware, such as between the feed and reflector.

5.6.2.2 C/L-Band Maritime Antenna Subsystem

•

The C/L band Maritime antenna subsystem provides communications

at 1.5-1.7 GHz. 3.6-3.65 GHz, and 6.425 - 6.441 GHz bands. The

polarization is circular. The purpose of the antenna is to

5-240
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5-241
ORIGINAL PAGE 8S

OF POOR QUALITY

Table 5.6.2-1

io VI-B Payload Summary

Eastern Pacific Maritime C/L-Band

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5-242

Ford Aerospace &

Communications Corporation
Ford Aerospace &

Communications Corporation

provide a beam to cover the eastern Pacific Region, as shown in

Figure 5.6.2-2.

The antenna will consist of 3 solid reflectors; a 1.2 meter

reflector for 1.6 GHz band, a 0.5 meter reflector for 3.6 GHz

band. and a 0.35 meter reflector for 6.4 GHz band. Each

reflector will be illuminated by a feed. A polarizer is employed

at each feed to produce circular polarization. Figure 5.6.2-3

presents the antenna radiation patterns. The edge of coverage

gain is 18 dBi.

All technologies required in this system are well developed.

The level of risk of the technology items is low.

5.6.2.3 Maritime Transponder Subsystem

See 5.5.3.3.

5.6.3 C-Band Non-CONUS FSS Pavload

5.6.3.1' Overview of C-Band Non-CONUS FSS Payload

This payload provides a nine-times re-use of the 500 MHz C-Band

FSS bandwidth and provides all of the projected non-CONUS

domestic demand for Region 2. except Canada. Brazil and Mexico.

These three countries require the use of the Ku-Band Payload

described subsequently. Also provided is the international

routing of all Region 2 Intelsat traffic via the POR-ISL. The

Canadian domestic traffic is also routed to the on-board baseband

processor for routing to the eastern ISL. the western (POR) ISL.

or back to Canadian domestic. It is assumed that the Canadian

system would operate in . a SS TDMA digital format from the

ground. However, added flexibility could be provided via on

board A-to-D conversion, as discussed in Scenario VI-A. Due to

the interconnectivety of the C and Ku-Bands. the block diagrams

5-243
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5-244
Ford Aerospace &

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L PAGE US

©F POOR QUALHTY

Figure 5.6.2-3 C-Band Antenna Pattern

B /

CONTOU R DRT R

SYMBOL . LEVEL

-3.000 08dbl)

-5.000

For satellite position

at 101 VI

5-245
Ford Aerospace &

Communications Corporation

have been combined and it was easier to break the block diagrams

in areas of coverage: Canadian. Mexican and Caribbean, and South

American. The block diagrams for these three areas are shown in

Figures 5.6.3-1. 5.6.3-2 and 5.6.3-3. respectively. The

subsequent subsections describe only the C-Band antenna and

transponder subsystem.

Table 5.6.3-1 shows the estimated weight, power, and volume for

low risk (emerging) technology and high risk (projected) technology for the transponder and antenna. Also included in the

estimates are the coax, waveguide, and harness interconnects,

plus an estimate for integration hardware to put the components

together and provide necessary brackets for support and

mounting. This does not include any structure or satellite

mounting hardware, such as between the feed and reflector.

5.6.3.2 C-Band Non-U.S. Antenna Subsystem

The C-band non-U.S. antenna subsystem provides transmission at

4 GHz and reception at 6 GHz of dually circular-polarized

communications signals.

The purpose of the C-band antenna is to provide 9 beams to

cover the North and South American continents, excluding the

United States, as shown in Figure 5.6.3-4. The combination of

co-polarization and cross-polarization isolations among these

beams provides the required interbeam isolation for the system.

Table 5.6.3-2 summarizes the C-Band antenna subsystem requirements.

The C-Band antenna will consist of a 9 meter unfurlable

reflector illuminated by an array of feed elements. A polarizer

is employed in each feed to produce circular polarization. The

incorporation of a diplexer at each feed allows the feed array to

operate in both the transmit and receive bands. Figure 5.6.3-5

shows the C-band antenna configuration. Figures 5.6.3-6 to

5-246
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5-248
Table 5.6.3-1

Scenario VI-B Transponder Summary

C-Band Non-U.S. Domestic & Regional

IYY

ITEM

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9

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11

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MARGIN REQUIRED

TOTAL ANTENNA

TOTAL PAYLOAD

1

1

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10

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0.9

141.5

0.7

4.2

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0.14

27

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2

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50

60

10%

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320

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18.6

5.4

141.5

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56.8

624.5

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576

7050

6480

32400

360

576

126

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, . <^&rS^> Ford Aerospace &

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Ford Aerospace &

Communications Corporation

Figure 5.6.3-4 C-Band Non-U.S. Antenna Coverage Area Reguirement

MflX.

THET R

10.000

5-250
Ford Aerospace &

Communications Corporation

Figure 5.6.3.5 C-Band Non-U.S. Unfurlable Reflector

Antenna Configuration

5-251
Ford Aerospace &

Communications Corporation

5.6.3-14 present the antenna radiation for each beam,

predicted edge-of-coverage gain in given in Table 5.6.3-3.

The

Table 5.6.3-2

C-Band Non-U.S. Antenna Subsystem Requirements

Parameters Requirements

Frequency

Polarization

Coverage

Area

Isolation

Transmit:

Receive:

Dual CP

4 Ghz

6 Ghz

3 beams for Canada

6 Beams for Central/South America

27 dB

Table 5.6.3-3

C-Band Non-U.S. Antenna Gain

Coverage

1 RCP

2 LCP

3 RCP

4 RCP

5 LCP

6 RCP

7 LCP

8 RCP

9 LCP

Gain

29.0

31.6

31.5

31.5

30.7

27.5

26.3

24.7

31.6

Theoretically, the surface tolerance of an unfurlable reflector

can be controlled to meet the antenna gain and cross-polarization

requirements. In practice, the increase in costs and weight to

meet certain electrical requirements may be astronomical and

impractical. In addition. the requirements on the surface

tolerance for a multiple beam antenna system are more stringent

5-252
Ford Aerospace &

Communications Corporation

Figure 5.6.3-6 Western Canadian Contour Plot

CONTOU R DflTfl

SYMBO L LEVEL

fl

B

C

D

E

F

G

0.000

-3.000 (29.0dBi )

-5.000

-8.000

-10.00 0

-15.000

-20.000 5-253
Ford Aerospace &

Communications Corporation

Figure 5.6.3-7 Central Canadian Contour Plot

CONTOU R DRTR

SYMBOL LEVEL

R

B

C

D

E

F

G

0.000

-3.000 (31.6 dBi)

-5.000 •

-8.000

-10.000

-15.000

-20.000 5-254
Ford Aerospace &

Communications Corporation

Figure 5.6.3-8 Eastern Canadian Contour Plot

CONTOU R DflTfl

SYMBO L LEVEL

fl

B

C

D

E

F

G

0.00 0

-3. 000 (31.5 dBi)

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-15.000

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Ford Aerospace &

Communications Corporation

Figure 5.6.3-9

IS

OF POOR QUALITY

Northern Mexico Contour Plot

CONTOU R DflTfl

SYMBOL LEVEL

R

B

C

D

E

F

G

0.000

-3. 000 (31.5 dBi)

-5.000

-8.000

-10.000

-15.000

-20.000 5-256
Ford Aerospace &

Communications Corporation

Figure 5.6.3-10 Southern Mexico Contour Plot

CONTOU R DRTfl

SYMBOL LEVEL

fl

B

C

D

E

F

G

0.000

-3. 000 (30.7 dBi)

-5.000

-8.000

-10.000

-15.000

-20.000

5-257
Ford Aerospace &

Communications Corporation

Figure 5.6.3-11 Central American/Caribbean Contour .Plot

CONTOU R DflTfl

SYMBO L LEVEL

fl

B

C

D

E

F

G

0.000

-3. 000 (27.5 dBi)

-5.000

-8.000

-10.000

-15.000

-20.000

5-258
Ford Aerospace &

Communications Corporation

Figure 5.6.3-12 Western South American Contour Plot

CONTOU R DflTfl

SYMBOL LEVEL

fl

B

C .

D

E

F

G

0.000

-3.000 (26.3 dBi)

-5.000

-8.000

-10.000

-15.000

-20.000

5-259
Aerospace &

Communications Corporation

Figure 5.6.3-13 Eastern South American Contour Plot

CONTOUR DflTfl

SYMBOL LEVEL

R

B

C

D

E

F

G

0.000

-3. 000 (24.7 dBi)

-5.000

-8.000

-10.00 0

-15.000

-20.000

5-260
Ford Aerospace &

Communications Corporation

Figure 5.6.3-14 Eastern Brazil Contour Plot

CONTOU R DflTfl

SYMBO L LEVEL

fl

B

C

D

E

F

G

0.00 0

-3. 000 (31.6 dBi)

-5.000

-8.000

-1-0. 000

-15.000

-20.000

5-261
Ford Aerospace &

Communications Corporation

than those for a pencil beam. Further study should be conducted

to evaluate the impact of the costs and weight for the system on

the cross-polarization degradation, change of the beam shape, and

the antenna gain. Another critical technology item is the dualband polarizer for 6/4 GHz band. In order to meet the 27 dB

cross-polarization isolation, the axial ratio levels of less than

0.2 dB over the frequency band are required. From mechanical and

integration points of view, it should also be compact and light

weight. The assessment of these two critical technology items is

given in Table 3.6.3-4.

Table 5.6.3-4

Assessment of Level of Risk

of the Critical Technology Items

Item Low Risk High Risk

Unfurlable

Reflector

Dual Band

Polarizer

Needs development

Needs Development

Needs development

Needs development

5.6.3.3 C-Band Transponder. Non-U.S.. Domestic and Regional

Service

The C-Band transponder subsystem consists of nine

independent. 12 channel transponders. Hence, it has a total

capacity of 108 channels, each having a bandwidth of 36 MHz.

The nine trans- ponders utilize the same 500 MHz FSS band,

having an uplink at 6 GHz and a downlink at 4 GHz. Three of

these transponders provide service to Canada, three to Mexico

and the Carribean. and three to South America. Crosslinks

between all channels of the Canadian C-band and Ku-band

transponders, between the even channels of the Mexican and

Carribean transponders, and between the even channels of the

262
Ford Aerospace &

Communications Corporation

C-Band South American and Ku-band Brazil transponders, are made

at the 4 GHz IF by switch matrices.

Each of the nine 6 GHz inputs from the antenna feed assembly

is filtered by an input preselector and then amplified and

downconverted to 4 GHz by the receiver. The 500 MHz IF band is

subdidived by an input multiplexer into twelve. 36 MHz

channels. The filters of the input multiplexer also provide

the required narrow band receive filtering responses.

For the three Canadian transponders, twelve 4x4 switch

matrices enable signals in any uplink channel of one

transponder to be connected to the same channel in any of the

other two C-Band transponders, or with the same channel in the

Canadian Ku-Band transponder. For the three Mexican/Carribean

transponders, six 3x3 switch matrixes provide even channel

interconnections. The even channels of the three C-Band South

American transponders and the even channels of the two

Brazilian transponders are interconnected via six. 5x5 switch

matrices.

The channels are individually amplified by up to 8.5 watt

SSPA's which contain one or more variable gain amplifiers. The

latter permit automatic accommodation of varying uplink levels

using an AGC loop, and SSPA back-off via ground control. The

output of the SSPA in each set of twelve channels are combined

in a twelve channel output multiplexer, which also supplies the

required narrow band transmit filtering responses. The

downlink signals are further filtered by harmonic/bandpass

filters prior to transmission from the transmit antenna feed

assembly. The transponder subsystem features four for two

receiver redundancy and five for four SSPA redundancy.

5.6.3.3.1 6/4 GHz Receiver

See 5.2.2.3.1.

5-263
Ford Aerospace &

Communications Corporation

5.6.3.3.2 4 GHz Input Multiplexer

See 5.2.2.3.2.

5.6.3.3.3 RF Switch Matrix

See 5.2.3.3.3.

5.6.3.3.4 4 GHZ 8.5 Watt SSPA

See 5.2.2,3.3.

5.6.3.3.5 4 GHz Output Multiplexer

See 5.2.2.3.4.

5.6.3.3.6 Pre-Select and Harmonic Filters

See 5.2.2.3.5.

5.6.3.4 Baseband Processing

The baseband processor for this payload accepts 12. 72 Mb/s

input channels, demodulates them, and formats them into a TDMA

750 Mb/s data stream. This 750 Mb/s data stream is then routed

via the digital routing switch and routed with the odd and even

750 Mb/s data streams from the eastern satellite ISL and the

POR ISL. The five data streams are TDMA switched to the

appropriate downlink data stream. The odd and even 750 Mb/s

data streams for the eastern satellite ISL are fed to the

associated ISL modulator to transmit the 1.5 Gb/s data link.

The 750 Mb/s data stream routed to the Canadian downlink

processor is then TDMA routed to the appropriate data memory

and modulator to construct the downlink modulated spectrum in

the appropriate 36 MHz bandwidth transponder. Figure 5.6.3-15

is the block diagram of the baseband processor and switch.

5-264
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5-265
Ford Aerospace &

Communications Corporation

Since this processor is operating on the C-Band links, no

provision for FEC. variable power, or variable data rates have

been provided. The digital routing switch and data memories are

however, operating at about twice current, state-of-the-art

switching speeds to handle the 750 Mb/s data streams. In order

to be implemented in low risk technology, the system would have

to double the switch size and split the data into lower rate

components.

For high risk technology, it is assumed that additional VLSI

development and advances in speed and power would yield lighter

weight, lower power, and correspondingly lower volume. This is

an area where the custom VLSI work would not likely be done

without NASA/government subsidized effort.

5.6.4 Ku-Band Non-CONUS FSS Pavload

5.6.4.1 Overview of Ku-Band Non-CONUS FSS Payload

This payload provides the remaining domestic coverage that

could not be accommodated on the C-Band payload described in

Section 5.6.3. This results in a spot beam in Canada, use of

two Ku-band channels not used in the U.S. domestic beam 8H of

the Ku-Band payload described in Section 5.4.5, and dual

polarization use of domestic-Brazil coverage. Due to the

complexity of the interconnectivety. the block diagrams contain

both the C and Ku-Band elements. The block diagrams are broken

down by area of coverage, Canada. Mexico and Caribbean, and

South America. The block diagrams for these three areas of

coverage are shown in Figures 5.6.4-1. 5.6.4-2. and 5.6.4-3

respectively. The Ku-Band antenna subsystem uses the Ku-Band

U.S. domestic reflector with additional feed elements for the

Canadian spot beam and the Mexican coverage. The Brazil system

is an independent antenna system. The subsequent sub-sections

describe only the Ku-Band antenna and transponder subsystems.

5-266
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5-269
Ford Aerospace &

Communications Corporation

Table 5.6.4-1 shows the estimated weight, power, and volume

for low risk (emerging) technology and high risk (projected)

technology for the transponder and antenna. Also included in

the estimates are the coax, waveguide. and harness

interconnects, plus an estimate for integration hardware to put

the components together and provide necessary brackets for

support and mounting. This does not include any structure or

satellite mounting hardware, such as between the feed and

reflector.

5.6.4.2 Ku-Band Non-CONUS Antenna Subsystem

The Ku-Band non-CONUS antenna subsystem provides

transmission at 11 GHz and reception at 14 Ghz of dually linear

polarized communications signals for Ku-Band.

The purpose of the Ku-Band non-CONUS antenna is to provide a

spot beam in Canada, a shaped beam to cover Mexico, and another

one to cover Brazil, as depicted in Figure 5.6.4-4. The Canada

spot beam and Mexico beam will be generatd by adding additional

feed array to the 15' Ku-band FSS CONUS antenna system.

Theoreti- cally, another feed array might also be added to

produce the Brazil beam. However, the constituent beam of the

Brazil beam will be too far away from the on-axis beam. As

indicated in subsection 5.5.4.2, this will result in severe

phase aberration. Therefore, a 1.0 meter dual-gridded

reflector will be used to generate the Brazil beam. Figures

5.6.4-5 and 5.6.4-6 present the antenna radiations for the

Mexico and Brazil beams. The predicted antenna gain at the

edge-of-coverage is given in Table 5.6.4-2.

5.6.4.3 Ku-Band Transponder. Non-U.S.. Domestic and Regional

The Ku-Band Transponder subsystem consists of one 12 channel

Canadian transponder, one 2 channel Mexican transponder, and

two 12 channel Brazilian transponders, and hence has a total

5-270
ORIGINAL PAGE IS

OF POOR QUALfTY

Table 5.6.4-1

Scenario VI-B Payload Summary

Ku-Band Non-U.S. Domestic and Regional

ORIGINAL PAGE IS

OF POOR QUALITY

ITEM

1

7

3

A

5

6

7

8

9

10

11

12

13

14

IS

Ifi

17

1R

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20

71

22

23

24

25

26

27

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33

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38

.

14/4 GHz RECEIVER

14/11 GHz RECEIVER

36 MHz INPUT MULTIPLEXER, 11 GHz, 6 channe

36 MHz INPUT MULTIPLEXER, 11 GHz. 2 Channe

5/4 REDUNDANCY SWITCH MATRIX. 11 GHz, Coax

Ring

P/L

QTY

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SSPAs \ 1 GH7 10 W (T\

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OUTPUT MULTIPLEXER, 11 GHz, 12 channel

(36 MHz)

HARMONIC FILTER. 11 GHz

PRESELECT FILTER, 14 GHz

SPDT SWITCHES, 14 GHz, Waveguide

TRANSFER SWITCHES, 14 GHz W/G

COAX . SET

WAVEGUIDE, SET

HARNESS

COMM CONTROL & INTERFACE

INTEGRATION HARDWARE, SET

MARGIN REQUIRED

TOTAL TRANSPONDER

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2

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1

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/,

6

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BRAZIL ANTENNA REFLECTOR (.DUAL GRIDDED) 1

BRAZIL FEED NETWORK/ VERTICAL 1

BRAZIL FEED, NETWORK, HORIZONTAL 1

MEX/CANADIAN FEED NETWORK, HORIZONTAL ^ 1

MARGIN REQUIREDTOTAL ANTENNA

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COMMENTS

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5-271

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5-274
Ford Aerospace &

Communications, Corporation

Table 5.6.4-2

Ku-Band Non-CONUS Antenna Gain

Coverage Gain dBi

Canada Spot Beam 48.8

Mexico 29.8

Brazil 27.3

capacity of 38 channels, each having a bandwidth of 36 Mhz.

The four transponders utilize the same 500 MHz FSS band, having

uplinks at 14 Ghz and downlinks at 11 Ghz. Crosslinks between

all channels of the Canadian Ku-Band transponder and the three

Canadian C-Band transponders are made at the 4 Ghz IF via a

switch matrix. Similar configurational switching is provided

between the even channels of the two Brazillian Ku-Band

transponders and the three South American C-Band transponders.

The 14 Ghz inputs from the beam forming network of the Mexican

receive antenna are filtered by an input preselector, then

amplified and down converted to 11 GHz by the receiver. For

the Canadian and Brazilian trans- ponders; however, the 14 Ghz

signals are downconverted to a 4 Ghz IF to facilitate beam

switching with C-Band transponders. In all cases, the receiver

output is fed to an input multiplexer which subdivides the 500

MHz IF band into twelve 36 MHz channels, while also providing

the required narrow band receive filtering responses.

The Brazilian input multiplexers are followed by six 5x5

switch matrices. The latter permit signals in any uplink

channels of the two Brazilian Ku-Band transponders to be

re-transmitted via any of the three South America C-Band

transponder output sections. Similarly, all twelve channels of

the Canadian Ku-band transponder can be connected to the

corresponding channels of the three Canadian C-Band

transponders.

5-275
Ford Aerospace &

Communications Corporation

With the exception of the two Mexican channels which have an

11 Ghz IF. each channel is first individually upconverted to 11

Ghz and then amplified by SSPAs. The latter contain one or

more variable gain amplifiers. which permit automatic

accommodation of varying uplink levels using an AGC loop, and

also up to 16 db of power amp back-off via ground control. For

the non-U.S. Domestic and regional Services, from 1 to 5 watt

SSPA's are necessary to ensure sufficient EIRP.

The outputs of the SSPA's in each transponder are combined in

an output multiplexer, which also provides the required narrow

band transmit filtering responses. The downlink signals are

further filtered by a harmonic bandpass filter prior to

transmission from the antenna 'feed assembly. The transponder

subsystem features 4 for 2 redundancy for the receivers and 5

for 4 redundancy for the SSPAs.

5.6.4.3.1 Ku-Band Receiver

5.6.4.3.1.1 14/11 GHz Receiver

See 5.2.5.3.

5.6.4.3.1.2 14/4 GHz Receiver

See 5.3.2.3.1.

5.6.4.3.2 Input Multiplexers

5.6.4.3.2.1 11 GHz Input Multiplexers

• '

See 5.2.5.3.2.

5.6.4.3.2.2 4 GHz Input Multiplexers

See 5.2.2.3.2.

5-276
Ford Aerospace &

Communications Corporation

5.6.4.3.3 RF Switch Matrix

See 5.2.3.3.3.

5.6.4.3.4 4/11 GHz Upconverter

See 5.2.6.3.4.

5.6.4.3.5 11 GHZ SSPAs

See 5.2.5.3.

5.6.4.3.6 11 GHz Output Multiplexers

See 5.2.5.3.6.

5.6.4.3.7 Pre-Select and Harmonic Filters

See 5.2.2.3.5.

5-6.5 Ka-Band FSS Payload

This payload is identical to the Ka-Band FSS payload

described in Scenario II. See 5.2.3 for detailed description.

5.6.6 Ka-Band Scan Payload

This payload is identical to the Ka-Band Scan payload

described in Scenario II. See 5.2.4 for detailed description.

5.6.7 Ku-Band FSS Payload

This payload is identical to the Ku-Band Payload described

in Scenario V. See 5.4.5 for detailed description.

5-277
Ford Aerospace &

Communications Corporation

5.6.8 60 GHz Inter-Satellite Link (ISL)

The iSL's on ths payload are identical to those defined in

5.5.8. with the exception that the both the east and west ISL's

only, require 1 each duplex channel. Each ISL carries a 1.5

Gbps data link in each direction. These ISL links are

currently being developed on a NASA Goddard technology

contract. Assuming this development continues to completion,

no other funding would be required. Table 5.6.8-1 shows the

weight power, and volume for low risk (emerging) technology and

high risk (projected) technology for the transponder and

antenna. Also included in the estimates are the coax,

waveguide, and harness intaerconnects. plus an estimate for

integration hardware to put the components together and provide

necessary brackets for support and mounting. This does not

include any structure or satellite mounting hardware, such as

between the feed and reflector.

5-278
Table 5.^.8-1

ORIGINAL PAGE IS

OF POOR QUALITY

Scenario VI-B - Payload Summary

60 GHz ISL

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5-279

Ford Aerospace &

Communications Corporation
Ford Aerospace &

Communications Corporation

SECTION INDEX

Page

6.0 PAYLOAD COSTING (TASK 5) 6-1

6.1 OVERVIEW 6-1

6.2 COST FORECASTING METHODOLOGY 6-1

6.2.1 Approach 6-1

6.2.2 PRICE Cost Model 6-2

6.3 PAYLOAD COST DETAILS 6-5

6.3.1 Summary 6-5

6.3.2 Payload Cost Sheets 6-5

6.4 SCENARIO PAYLOAD COST 6-40

6.5 SCENARIO PLATFORM COST 6-40
Ford Aerospace &

Communications Corporation

6.0 PAYLOAD COSTING (TASK 5)

6.1 OVERVIEW

The purpose of task 5 is to provide costing information for

the five scenario pay loads developed in task 4. All costs are

expressed in terms of constant 1984 dollars. Sufficient detail

is included in order to provide cost information on individual

payload elements as well as the assembled payload as a whole. A

qualitative assessment of associated ground segment costs is

subsequently provided in section 8 in order to evaluate the

impact upon full system costs.

Section 6.2 describes the Ford Aerospace cost forecasting

methodology. Extensive use of the PRICE H model is included.

Fine structure cost details on individual payload elements,

i.e.. C-band FSS or Ku-band DBS etc.. down to the component

level is presented in section 6.3.

A summary of total individual scenario composite payloads and

associated integration costs is presented in section 6.4.

A summary of total flight system costs for each of the five

scenarios is presented in section 6.5. This is the composite of

definitive scenario payload cost and qualitative assessment, bus

costs, and launch costs.

6.2 COST FORECASTING METHODOLOGY

6.2.1 Approach

Basic data in the form of quantity, weight, volume, cost, and

etc., from an FACC produced C-band payload (transponder and

antenna) system, and a Ku-Band payload system, were used for the

calibration and validation of the PRICE H model. The data, for

6-1
Ford Aerospace &

Communications Corporation

each component of the payload system, was formatted for

PRICE H model. The model then predicted the cost, in constant

1984 dollars, for each component. Data on purchased components

was formatted from recent actual purchase cost or current

quotation estimates. All components for a given frequency band

were then combined together, integration and test data added,

and the whole data set input to the model.

Actual cost history for each frequency band system was then

compared to the total cost just predicted through PRICE H.

Once the FACC cost factors input to the model were output to

the exact actual cost, the factors were noted and then applied

to the equivalent frequency band scenario of the study.

Scenario data was extracted from the payload sheets of section S

of this report. The resulting output from the PRICE H model is

a prediction of the recurring cost to build that whole system at

FACC. Since the factors were applied at the system level the

costs of individual assemblies and components will vary, but

over all they will balance for a valid output.

In the case of the Ka-band equipment, no current flight data

was available so the relative complexity to Ku-band equipment

was estimated and the resulting PRICE H output compared with

engineering estimates for reasonableness.

6.2.2 PRICE Cost Model

The PRICE (Parametric Review of Information for Costing and

Evaluation) Hardware Model is a computerized method for deriving

cost estimates of electromechanical hardware assemblies and

systems. It was developed by RCA in the early 1960's, and has

been used at Ford Aerospace since 1976 to estimate space system

costs.

6-2
Ford Aerospace &

Communications Corporation

The method used in PRICE H to model the estimating procedure

is parametric. Therefore, when the model calculates a cost for

manufacturing, it does not use a parts list and labor resource

chart, but rather a parametric representation of the parts and

labor costs.

The fundamental data used in the PRICE Hardware Model are as

follows:

0 Quantities of equipment to be developed, produced,

modified. purchased. furnished and/or integrated and

tested.

0 Schedules for development, production, procurement.

modification, integration and testing, including lead

time for set-up, parts procurement, and redesign.

0 Hardware geometry consisting of size. weight of

electronic and structural elements. and electronic

packaging density.

0 Amount of new design required and complexity of the

development engineering task.

0 Hardware structural and electronic design repeat.

0 Operational environment and specification requirements of

the hardware.

0 Type and manufacturing complexity of the structural/

mechanical and electronics portions of the hardware.

0 Fabrication process to be used for production.

0 Pertinent escalation rates and mark-ups for General and

Administrative charges, profit. IR&D. cost of money, and

purchased item handling.

0 Technological improvement.

0 Yield considerations for hardware development.

The fundamental characteristic of the parametric inputs is

that of interrelationship. A change in any one parameter is

usually not localized to one cost element, but rather, may have

6-3
Ford Aerospace &

Communications Corporation

a direct effect on a few cost elements, and an indirect effect

on many more. Consider the impact of a change in quantity.

Certainly this would cause a change in manufacturing cost. But,

it might also affect the fabrication process and. hence, the

cost of tooling equipment. In addition, a change in quantity

would probably have a schedule effect and so the cost due to

escalation would differ. A filtered impact on integration and

testing, sustaining engineering, and project management would

almost certainly result from a change in quantity. This-dynamic

effect is characteristic of most input variables.

Conducting a PRICE H analysis is, therefore, a two step

process. The first step being the creation and storage of the

hardware parametric data; and the second step being the

conversational dialogue between the user and the PRICE H Model

when the stored data is used to estimate costs.

Adaptation of the model to new products and new situations is

facilitated by the ability to run PRICE H in reverse on existing

equipment or past programs, using actual costs as inputs. In

this mode. the output is not cost, but the manufacturing

complexity that matches the cost and other input parameters.

Once a user has performed this process on a number of case

histories, a discernable pattern usually emerges with respect to

the manufacturing complexities. This pattern is then refined

and tested on other programs to yield the accounting and product

calibrations that properly adapts PRICE H to the new situation.

The inescapable conclusion to be drawn from all of this is

that since PRICE H must be adapted, and since successful

adaptation is accomplished with sound data, the user must

validate the data used for calibration. Although this is

usually a tedious and arduous task, its performance will

ultimately save more time than it takes.

6-4
Ford Aerospace &

Communications Corporation

The PRICE H Model is actually a group or system of cost

estimating and evaluation models and auxiliary programs. In

addition to estimating costs to develop, produce, modify,

integrate, and test hardware, the PRICE H system also includes

methods for:

o Calculating complexity factors from any known cost

o Thru-putting costs not estimated by PRICE H

o Estimating the costs of multiple lot productions

o Calculating manufacturing complexities of non-homogeneous

assemblies

o Calculating field reliability

6.3 PAYLOAD COST DETAILS

6.3.1 Summary

A summary of the projected costs derived from the PRICE H

outputs associated with each of the various payload elements is

shown in Table 6.3-1.

6.3.2 Payload Cost Sheets

The output of PRICE H is an abbreviated format which lists

the total cost of each assembly and a system cost summary. An

explanation of the output format is as follow:

Header Lines. Most of the header lines on each portion of the

output are self-explanatory. The metric units of measure are:

weight in kilograms and volume in cubic decimeters. The Global

File contains calibration factors used to cause the model to

operate in the manner FACC accumulates cost, e.g.. tooling and

test equipment costs are included in recurring (manufacturing)

production costs. The Escalation filename is blank, since we

did not escalate the costs through the model on these runs.

6-5
Ford Aerospace &

Communications Corporation

Table 6.3-1

Costs of Payload Subsystems

Subsystem

C-Band. FSS

C-Band. FSS

C-Band. Maritime Atlantic

C-Band. Maritime Pacific

C-Band. International

C-Band. Non U.S.

Ku-Band. Non U.S.

Ku-Band. FSS

Ku-Band, FSS

Ku-Band. FSS

Ku-Band. DBS

Ku-Band. DBS

Ka-Band. FSS

Ka-Band. SCAN

60 GHz. ISL

60 GHZ. ISL

Table

Cost

($M)

4.5

7.8

3.4

2.4

27.8

27.1

15.7

15.2

28.7

32.0

11.3

38.5

20.0

30.1

5.1

4.3

Used In Reference

Scenarios For Details

II

V. VI-A

VI -A

VI-B

VI-A

VI-B

VI-B

II

IV

V. VI-A. VI-B

II

IV

II. V. VI-A.

VI-B

II, V. VI-A.

VI-B

VI-A

VI-B

6.3-2

6.3-3

6.3-4

6.3-5

6.3-6

6.3-7

6.3-8

6.3-9

6.3-10

' 6.3-11

6.3-12

6.3-13

6.3-14

6.3-15

6.3-16A

6.3-16B

6-6
Ford Aerospace &

Communications Corporation

* ' i

Also shown is the Julian date the model was run to generate the

output.

System Cost Detail. The upper portion of the output is a

descriptive listing of each assembly or component used in a

pa/load with it's associated total cost. The total cost for

system integration and test is also listed here. The

descriptive detail and basic data for each output was extracted

from the payload sheets of section 5 of this report.

System Cost Summary. This lower portion of the output sheet

displays the total production-engineering and productionmanufacturing costs calculated by PRICE H. with each broken into

the cost categories shown. Engineering production costs are

those engineering costs associated with the recurring production

run only. Production-production costs are the touch labor and

material costs to produce the whole assembly. Tooling and test

equipment costs are included in the production-production cost.

Also shown is the total of all purchased items. In all

payloads, except the 60 GHz ISLs, purchased items include the

antenna reflectors. The ISL antenna assembly was costed as

though it was manufactured completely in-house.

Cost Ranges. This section shows a cost spread for the total

cost. All of the algorithms which are used in the PRICE H model

have been developed through regression analysis and therefore

have an inherent statistical error. When these errors are added

up over all the algorithms used in the cost calculations, they

produce a cost distribution around a mean (or center) value.

The From and To costs include the one sigma variation from that

mean.

The detailed PRICE cost model estimates are shown in Tables

6.3-2 through 6.3-16 for each of the payload configurations.

6-7
Ford Aerospace &

Communications Corporation ORIGINAL PAGE IS

®C POOR QUAlfTY

Table 6.3-2

Cost Of C-band FSS Pavload For Scenario II

INPUT FILENAME: CPPS1M 16-JUN-85 17:34

(185117) ESCALATION FILENAME:

PROGRAM COST<* 1000) DEVELOPMENT PRODUCTION TOTAL COST

RCVR, C--BAND, 6/1 GHZ, SCENARIO II, C-BAND FSS HUNTER MAY

TOTAL COST - 283. 283.

INPUT MUX, 6 CHAN, 36 MHZ

TOTAL COST - . 177. 177.

MATRIX, REDUNDANCY SUITCH <RING) 5/1, COAX.

TOTAL COST - 153. 153.

COMM CONTROL ?, INTERFACE, 3 EA

TOTAL COST - 300. 300.

3SPA, 1GHZ, 8.5UI WITH 3 VGAS

TOTAL COST - 3011. 3011.

MUX, OUTPUT, 6 CHAN

TOTAL COST - 171. 171.

HYBRID, 3DB

TOTAL COST - 3. 3.

SWITCH, SPDT, COAX, DUG 378395

TOJAL COST ' ' 9. 9.

SUITCH, TRANSFER, COAX, DUG 378399

TOTAL COST - 3. 3.

FILTER, 1 GHZ, HARMONIC, DUG 378133

TOTAL COST - 33. 33.

FILTER, 6GHZ, PRESELECT, DUG 278130

TOTAL COST - 3. 8.

FEED, ANT, VERT & HOR

TOTAL COST - 319. 21.9.

REFLECTOR, ANT DUAL GRIDDED

TOTAL COST - 700. 700.

I & T, SCENARIO II, C-BAND FSS HUNTER MAY 35

TOTAL COST 0. 171. 171.

6-8
Ford Aerospace &

Communications Corporation

table 6.3-2 (Continued)

Cost Of C-band FSS Payload For Scenario II

INPUT FILENAME: CPPSlh 16-JUN--85 17:24

(185147) ESCALATION FILENAME:

TOTAL COST, UITH INTEGRATION COST

PROGRAM COST(* 1000)

ENGINEERING

DRAFTING

DESIGN

SYSTEMS

PROJ MGMT

DATA

SUBTOTAL(ENG)

MANUFACTURING

PRODUCT ION

PROTOTYPE

TO01...-TEST EQ

PURCH ITEMS

SUB TOTAL. (MFG)

TOTAL COST

COST RANGES

FROM

CENTER

TO

DEVELOPMENT

0.

0»

0.

0.

0.

0.

0.

0,

0.

0.

0.

DEVELOPMENT

0.

0.

A

PRODUCTION

84.

402.

227.

109.

822.

2900.

0.

756.

•"i / i:: r.:

.'• 6 ..<_." .

4478.

PRODUCTION

4178.

4473.

4722.

TOTAL COST

84.

402.

0.

227.

109.

822.

2900.

0.

0.

756.

3655.

4478.

TOTAL COST

4178.

4478.

4723.

W X- X- * * «• «• * * K * «•* V: * X- W -X- X- * * *• * «• X K * * * * * * «• « * X- X- S » K » * X- X- # * * * * -X- X- #*#*#»** X- X- * K- * -X- W X

«• SYSTEM UT '87.84 SYSTEM US 82.72 *

* SYSTEM SERIES MTBF MRS. 2800 AV SYSTEM COST 4478 -x-

«• -X- «• » X- U X- -X- -X- -X- X- -X- •» * * * * -X- «*###•** -X- X- * •* X -X- * * -X- X- X- # * -X- W * * X- * X- •«• •«• «• -X- X -X- * # * * •» » «• •» X- -X- -X -X -X 

6-9
Ford Aerospace &

Communications Corporation

Table 6.3-3

Cost Of C-band FSS Payload For Scenario V And VI-A

INPUT FILENAME: C.PPS2M 19-JUN--85 20:24

(185147) ESCALATION FILENAME:

PROGRAM COST($ 1000) DEVELOPMENT PRODUCTION . TOTAL COST

RCVR, 6/4 GI-IZ; SCENARIO V & VI-A, C-BAND FSS HUNTER MAY 85

TOTAL COST - 462. 462.

MUXr INPUT, 12 CHAN, 36 MHZ

TOTAL COST - 315. 315.

MATRIX, BEAM SWITCHING, 4X4, 12 EA

TOTAL COST - 660. 660.

MATRIX, REDUNDANCY SWITCH (RING) 5/4, COAX

TOTAL COST - 263. P63.

COMM CONTROL & INTERFACE, 2 EA

TOTAL COST - 200. 200.

SSPA, 4 GHZ, 4.0 W. WITH 2 VGAS

TOTAL COST -- 2776. 2976.

MUX, OUTPUT, 12 CHAN, 36 MHZ

TOTAL COST - 311. 311.

SWITCH, SPOT, COAX, DWG 278395

-TOTAL COST •- 35. 35.

SWITCH, TRANSFER, COAX, DWG 278397

TOTAL COST - 6. 6.

FILTER, 4 GHZ, HARMONIC, DWG 278423

TOTAL COST - 224. SP4.

FILTER, 6 GHZ, PRESELECT, DWG 278420

TOTAL COST - 16. 16.

FEED, ANTENNA, VERTICAL £ HORIZONTAL

TOTAL COST - 465. 465.

REFLECTOR, ANTENNA, DUAL GRIDDED, 4.6M

TOTAL COST - 1100. 1:100.

I f, T, SCENARIO V & VI-A, C-BAND HUNTER MAY 85

TOTAL COST 0. 835. 8D5.

6-10
Ford Aerospace &

Communications Corporation

Table 6.3-3 (Continued)

Cost Of C-band FSS Payload For Scenario V And VI-A

INPUT FILENAME: CPPS2M 19-JUN-85 30:24

(185147) ESCALATION FILENAME:

TOTAL. COST, UITH INTEGRATION COST

PROGRAM COST<$ 1000)

ENGINEERING

DRAFTING

DESIGN

SYSTEMS

PROJ MGMT

DATA

SUBTQTAL(ENG)

MANUFACTURING

PRODUCTION

PROTOTYPE

TOOL.--TEST EG

PURCH ITEMS

SUBTOTAL(MFG)

TOTAL COST

COST RANGES

FROM

CENTER

TO

DEVELOPMENT

0.

0.

0.

0.

0.

0.

0.

0.

0.

0.

0.

DEVELOPMENT

0.

0.

0.

PRODUCTION

126.

591.

352.

168.

1338.

5249.

0.

1381.

6631.

7869.

PRODUCTION

7336.

7869.

8320.

TOTAL COST

591.

0.

352.

168.

J.238.

5249.

0.

0.

1381.

6631.

7069.

TOTAL COST

7326.

7869.

8320.

* * X- X X A :(• X- X- X- « X X- X- X- * K X- X- X X- « «• MKMMKttMM K # «• * «• « K- X- * K * «• * * -X- X * X- X- » X- X- X- K X- tt M- K X- X- X- X X 

* SYSTEM UT 251.40 SYSTEM US 240.00 *

* SYS I EM SERIES MTBF MRS. 1112 AV SYSTEM COST 7869 *

*******X** ******** **********************XX-X-««XX-«»X-X**X**X*X X-XX-X XX* X -X )(•»•«***

6-11
Ford Aerospace & -.; .

Communications Corporation ORIGfNAl "P&Q£• •($

OF POOR QUAUTY

Table 6.3-4

Cost Of C/L-band Maritime Payload For Scenario VI-A

INPUT FILENAME: CPPS13M 16-JUN-85 17:43

<185147) ESCALATION FILENAME:

PROGRAM COST<* 1000) DEVELOPMENT PRODUCTION TOTAL COST

RCVR, 6.0/1.5 GHZ, SCEN VI-A, U. ATLANTIC MARITIME C/L BAND

TOTAL COST - 264. 264.

L-BAND HIGH POWER AMPLIFIER 100U

TOTAL COST - 1200- 1900.

BP/HARMON1C FILTER 1.5 GHZ

TOTAL COST - 5. 5.

CHANNEL FILTER 1.5 GHZ

TOTAL COST . - 5. 5.

PRESELECT FILTER 6 GHZ

TOTAL. COST - 4. 4.

SPOT SWITCH 6 GHZ CPAX 1.5 GHZ COAX

TOTAL COST - 18. 18.

RECEIVER, DUAL. CONVERSION, 1.6/0.36

TOTAL COST - 381. 381.

C-I3AND HIGH POWER AMPLIFIER ?U

TOTAL COST - 2. 2.

PRESELECT FILTER 0.36 GHZ

TOTAL COST - 4. 4.

SPOT SWITCH COAX 0.36 GHZ, 4 GHZ

TOTAL COST - 18. 18.

BP/HARMONIC FILTER 4 GHZ W/G

TOTAL COST - 5. 5.

CHANNEL. FILTER 4 GHZ CAVITY DIEL

TOTAL COST - 4. 4.

L-BAND LINEARIZER

TOTAL COST - 2. 9.

I... -BAND ANTENNA REFLECTOR TX/RX 3M

TOTAL COST - 350. 350.

L-BAND FEED

TOTAL COST - 353. 353.

C-BAND ANTENNA REFLECTOR TX 1M

TOTAL COST - 39. 39.

C-BAND TX FEED

TOTAL COST ••• 199. 199.

C-BAND ANTENNA REFLECTOR RX 0.75M

TOTAL COST - 22. 23.

C-BAND RX FEED

TOTAL COST - 116. 116.

I & T, SCENARIO VI-A, W. ATLANTIC MARITME C/L-BAND HUNTER

TOTAL COST 0. 3?5. 395.

6-12
Ford Aerospace &

Communications Corporation

ORfGfNAL P£QE {3

OF POOR-.0UALITY

Table 6.3-4 (Continued)

Cost Of C/L-band Maritime Payload For Scenario VI-A

INPUT FILENAME: CPPS13M 16-JUN-85 17:48

(135147) ESCALATION FILENAME:

TOTAL COST, WITH INTEGRATION COST

PROGRAM COST<$ 1000) DEVELOPMENT

ENGINEERING

DRAFTING 0.

DESIGN 0.

SYSTEMS 0.

PROJ MGMT 0.

DATA 0.

SUBTOTAL(ENG) 0.

MANUFACTURING

PRODUCTION

PROTOTYPE

TOOL-TEST EG)

PURC.H ITEMS

SUBTOTAL(MFC)

TOTAL COST

COST RANGES

FROM

CENTER

TO

0.

0.

0.

0.

0..

DEVELOPMENT

0..

0 TM

PRODUCTION

109.

583.

235.

120.

997,

711.

0.

1676.

2397.

3384.

PRODUCTION

339?.

3384.

3456.

TOTAL. COST

1.09.

533.

0.

235.

120.

997.

711.

0.

0 „

1676.

2387.

3384.

TOTAL COST

o p'./ 9 _

3384.

3456.

X- * -if- K- X- K- •)<• X- X- X- X- V- V- ft V:

 :f: V: X- •«• * V: «• » X- » X: X- •«• W «• W » * » » »•» W K )': K •» •>(• •» » -w X: >(• X: X: •» X- * X '* «• *• * V: *• » -X: X- 

* SYSTEM UT • 35.14 SYSTEM US 84.30 *

*• SYSTEM SERIES MTBF MRS. 2477 A1,' SYSTEM COST 3384 *•

•x- «• -^ * # «• x- * * * -x- * •«• •» •» •» «• -x-» «• •» «• M- •» » * * * »• «• «• «• * x- * -x- * * -x- * x- # * * x- -x- -y- x- -x-» * •» » * x *: * » «•» * * * * 

6-13
Ford Aerospace & .

Communications Corporation

Table 6.3-5

Cost Of C/L-band Maritime Pavload For Scenario VI-B

INPUT FILENAME: CPPS14M 16-JUN-35 17:49

(185147) ESCALATION FILENAME:

PROGRAM COST<$ 1000) DEVELOPMENT PRODUCTION TOTAL. COST

RCVR, 6.0/1.5 GHZ, SCENARIO VI-B, E. PACIFIC MARITIME C/L-B

TOTAL. COST " - - 264. 2.64.

I...-8AND HIGH POWER AMPLIFIER 100U

TOTAL COST - 1200. 1200.

BP/HARMON1C FILTER 1.5 GHZ

TOTAL COST -- 5.. 5.

CHANNEL FILTER 1.5 GHZ

TOTAL COST - 5. 5.

PRESELECT FILTER 6 GHZ

TOTAL COST - 4. 4.

SPOT 3UITCH 6 GHZ CPAX 1.5 GHZ COAX

TOTAL COST - 18. 18.

RECEIVER, DUAL. CONVERSION, 1.6/0.36

TOTAL COST - 381. 381.

C-BAND HIGH POWER AMPLIFIER 9U

TOTAL COST - 2. 2.

PRESELECT FILTER 0.36 GHZ

TOTAL. COST - 4. 4.

SPOT SWITCH COAX 0.36 GHZ, 4 GHZ

TOTAL COST - 18.. 18.

BP/HARMONIC FILTER 4 GHZ U/G

TOTAL COST - 5. 5.

CHANNEL FILTER 4 GHZ CAVITY DIEL

TOTAL COST - 4. 4.

L-BAND LT.NEARIZER

TOTAL COST - 40. 40.

L-BAND ANTENNA REFLECTOR TX/RX 1.2M

TOTAL COST - 56., 56.

L-BAND FEED

TOTAL COST - 42. 42.

C-BAND REFLECTOR TX 0.5M

TOTAL COST - 10. ' 10.

C-BAND TX FEED

TOTAL. COST - 26. 26.

C-BAND ANTENNA REFLECTOR RX 0.35M

TOTAL COST - 5. 5.

C-BAND RX FEED

TOTAL COST - 19.

I ?, T, SCENARIO" VI-A, U. ATLANTIC MARITME C/L-BAND HUNTER

TOTAL COST 0. 330.

6-14
Ford Aerospace &

Communications Corporation

ORIGINAL PAGE IS

OF POOR QUALITY

Table 6.3-5 (Continued)

Cost Of C/L-band Maritime Payload For Scenario VI-B

INPUT FILENAME: CPPS14M 16-JUN-85 17:4?

(185147) ESCALATION FILENAME:

TOTAL COST, UITH INTEGRATION COST

PROGRAM COST($ 1000)

ENGINEERING

DRAFTING

DESIGN

SYSTEMS

PROJ MGMT

DATA

SUBTOTAL(ENG>

MANUFACTURING

PRODUCTION

PROTOTYPE

TOOL-TEST EQ .

PURCH ITEMS

SUBTOTAL(MFG)

TOTAL COST

COST RANGES

FROM

CENTER

TO

DEVELOPMENT

0.

0.

0.

0.

0.

0.

0.

0.

0.

0.

0.

DEVELOPMENT

0.

0.

0.,

PRODUCTION

369.

76.

661.

400.

0.

1374.

1.774.

2435.

PRODUCTION

2383.

2435.

2481.,

TOTAL COST

.

365.

76.

66:1.

400.

0.

0.

1374.

1774.

TOTAL COST

2383.

2435.

248 1. •

¥• X- X- X- •* -V: V- * * X- X- X- V: X- ¥: X- X- X- X- X- V: » K- -X- X- X- *• -X- «• *• ft » * * -X- * X- X- ¥: V: » *• X- » X- X- V: X- X- X- W X- X X -X- X- * X- X- X- X- K •» 

* SYSTEM UT 46..99 SYSTEM US 46.15 *

» SYSTEM SERIES MTBF MRS. 2776 AV SYSTEM COST 2135 -*

•x- x- x- -x- x -x x- -x- * -x x- •:>!• * » x- «• * -x- * * -x- •» *:• * •»• * x x x •«• «• M- «• «• x- x •:«• * -M- «• -x x- x- -x x- * x- •» x- x- x -x- x -x- x x x- x- x- x- x

6-15
• '" '•' ' i V"'" . 'S 1- , Ford Aerospace &'

Communications Corporation

ORIGINAL PAGE IS

OF POOR QUALITY

Table 6.3-6

Cost Of C-band International Payload For Scenario VI-A

INPUT FILENAME: CPPS3M 10-JUL-85 13:52

(185147)

PROGRAM COST<* 1000) DEVELOPMENT PRODUCTION

RCVR, 6/4 GHZ, 18 EA, . SCENARIO. VI-A, C-BAND INTL.

TOTAL. COST - 835.

MUX, INPUT, 12 CHAN, 36 MHZ, 9 EA

TOTAL COST - 617.

MATRIX, BEAM SWITCHING, 9X9, 12 EA .

TOTAL COST - 2400.

BASEBAND PROCESSOR, INTERNATIONAL ROUTING, 1 EA

TOTAL COST - 8001.

MATRIX, REDUNDANCY-SWITCH (RING) 5/4, COAX, 27 EA

TOTAL COST - 290.

BASEBAND PROCESSOR, ADDED FOR CONUS KA-BAND, 1 EA

TOTAL COST - 2000.

SSPA, 4 GHZ, 4.5U. UITH 2 VGAS, 135 EA

TOTAL COST - 5504.

MATRIX, REDUNDANCY SWITCH (RING) 5/4, COAX, 27 EA

TOTAL COST . - 290.

MUX, OUTPUT, 12 CHAN, 36 MHZ, 9 EA

TOTAL COST . - 614.

FILTER, 4 GHZ, HARMONIC, DWG278423, 9 EA

TOTAL COST - 42.

FILTER, 6 GHZ, PRESELECT, DUG 278420-03, 9 EA

TOTAL COST - 36.

SWITCH, SPDT, COAX, DWG 278395, 9 EA

TOTAL COST - 40.

SWITCH, TRANSFER, COAX, DUG 278399, 4 EA

TOTAL COST - 6.

FEED, ANTENNA, VERTICAL & HORIZONTAL, 2 EA

TOTAL COST - 1643.

REFLECTOR, ANTENNA TX/RX, 5.0M, DUAL. GRIDDED, 1 EA

TOTAL COST - 1500.

FEED, ANTENNA, 4.0M, VERTICAL & HORIZONTAL, 2 EA

TOTAL COST - 515.

REFLECTOR, ANTENNA TX/RX, 4.0M, DUAL GRIDDED, 1 EATOTAL COST - 990.

I .& T, SCENARIO VI-A, C-BAND INTERNATIONAL HUNTER MAY 85

TOTAL COST 0. 2499.

ESCALATION FILENAME:

TOTAL COST

835.

617.

2400.

8001.

290.

2000.

':..:;• 04.

290.

614.

42.

36.

40.

6.

1643.

1500.

515.

790.

6-16
Ford Aerospace &

.Communications Corporation

ORIG5NAL PAGE IS

Table 6.3-4 (Continued) OF POOR

Cost Of C-band International Payload For Scenario VI-A

INPUT FILENAME: CPPS3M 10-JUL-85 13:52

(185147) ESCALATION FILENAME:

TOTAL COST, WITH INTEGRATION COST

PROGRAM COST (it 1000) DEVELOPMENT 'PRODUCTION TOTAL COST

ENGINEERING

DRAFTING 0. 659. 659.

DESIGN 0. 3346. 3346.

SYSTEMS 0. - 0.

PROJ MGMT 0. 1401. 1401.

DATA 0. 664. 664.

SUBTOTAL(ENG) 0. 6070. 6070.

MANUFACTURING

PRODUCTION - 19137. .19137.

PROTOTYPE . 0. - 0.

TOOL- TI£SI EiiT 0. 0. 0.

PURCH ITEMS 0. 3614. .'.,!'•!.

SUBTOTAL i MFC;) 0. 21751. 21751.

TOTAL COST 0. 27821. y/^ai.

COST RANGES DEVELOPMENT PRODUCTION TOTAL COST

FROM 0. 25913. a5913.

CENTER 0. 27821. 27821.

TO 0. 29341. 29341.

* * * X• X- «• X X- X * * «• * W X- X- « X- ft «• X- * * it X- * * X- X X- X- X- X «• K X- * tt * * X- X- *• X- * * X- » * * X- # «• X- «• X- X- «• X- X- X- 

* SYSTEM UT 820.32 SYSTEM US 775.40 *

* SYSTEM SERIES MTBF MRS. 957 AV SYSTEM COST 27821 *

#*#*«*»**#****** * * * * * * * * * -X * •«• * * * *• -X -X- * * X * •»• -X X- '* X •» -X- X * -X * « X * * X- •»•» * * * )( X M -X »-M -X X y .

6-17
Ford Aerospace &

Communications Corporation

Table 6.3-7

Cost Of C-band Non-U.S. Pavload For Scenario VI-B

INPUT FILENAME: CPPS4M 16-JUN-85 17:35

(185147) ESCALATION FILENAME:

PROGRAM CQST($ 1000) DEVELOPMENT PRODUCTION TOTAL COST

RCVR, 6/4GHZ, SCEN VI-B, C-BAND NON-CONUS HUNTER MAY 85

TOTAL COST - 835. 835.

MUX, 36MHZ INPUT, 4GHZ, 13 CHAN, SCEN VI-B, C-BAND, NON-CONU

TOTAL. COST - 675. 675.

MUX, 36MHZ INPUT, 4GHZ, 6 CHAN, SCEN VI-B, C-BAND, NON-CONUS

TOTAL COST - 105. 105.

MATRIX, BEAM SWITCHING, 4 GHZ, 4X4 COAX, 9EA

TOTAL COST - 500. 500.

MATRIX, REDUND SU (RING) 5/4, COAX, HUNTER/EDRIDGE MAY85

TOTAL COST - 341. 341.

MATRIX, BEAM SWITCHING, 4 GHZ, 5X5 COAX, 6 EA

TOTAL COST - 390. 390.

MATRIX, BEAM SWITCHING, 4 GHZ, 3X3 COAX, 6 EA

TOTAL COST - 299. 299.

BASEBAND PROCESSOR, 1EA

TOTAL. COST - 3001. 3001.-

SSPA, 4 GHZ, 4 SW, SCEN VI-B, C-BAND, NON-CONUS HUNTER MA

TOTAL COST - 5504. 550-1.

MUX, OUTPUT, 4 GHZ, 12 CHAN (36 MHZ), SCEN VI-B, C-BAND NONTOTAL COST - 614. 614.

FILTER, 4GHZ, HARMONIC, DUG 273423 INSAT LIMBURG 5/30/35

TOTAL COST - 42. 42.

FILTER. 6 GHZ, PRESELECT, DWWG 278420-03 INSAT LIMBURG

TOTAL COST - 36. . 36.

SWITCH, SPOT, COAX, DWG 278395-XX INSAT LIMBURG 5/30/85

TOTAL COST - 92. 92.

SWITCH, TRANSFER, COAX, DWG 278399-XX INSAT LIMBURG 5/30

TOTAL COST - 14. 14.

CUMM CONTROL & INTERFACE

TOTAL. COST - 200. 200..

FEED,ANT, NETWORK (TX/RX), SCEN VI-B,C-BAND, NON-U.S. HUNT

TOTAL COST - 2700. 2700.

REFL, ANT, UNFURL 9.0M, SCEN VI-B, C-BAND HUNTER MAY 85

TOTAL. COST - 10000. 10000.

I & T, SCEN VI-B, C-BAND. NON-U.S. DOMESTIC & REGIONAL HUNT

TOTAL COST 0. 1760. 1760,

6-18
Ford Aerospace &

Communications Corporation

ORIGINAL PAGE IS

OF POOR QUALITY

Table 6.3-7 (Continued)

Cost Of C-band Non-U.s. Payload For Scenario VI-B

INPUT FILENAME: CPPS4M 16-JUN-85 17:35

(185147) ' ESCALATION FILENAME:

TOTAL COST, UITH INTEGRATION COST

PROGRAM COSTC* 1000)

ENGINEERING

DRAFTING

DESIGN

SYSTEMS

PROJ MGMT

DATA

SUB TOTAL(ENG)

MANUFACTURING

PRODUCTION

PROTOTYPE

TO01...-TEST EG)

PURCH ITEMS

SUB TOTAL. <MFG)

TOTAL COST

COST RANGES

FROM

CRJTER

TO

DEVELOPMENJ

0.

0.

0.

0.

0.

0.

0.

DEVELOPMENT

0.

0..

0.

PRODUCTION

405.

1964.

941.

447.

3758.

37108.

PRODUCTION

25790.

27:1.08.

28183.

TOTAL COST

405.

1964.

0.

941.

44'y,

3758.

-

0.

A,,

0.

0.

13167.

-

0.

10184.

23351.

13167.

o „

0.

1.0184.

23351 .

27108.

TOTA! r

25770.

27108.

* V- X- X- » w. y; * X- *• X X- X X- -X- •* X- » X- * X- •» X- X- X- ¥: X- * -X- -X- * * ¥: * V: * V. V: «• X: V: X- X- X- X- * X- «• X- X- * -X- * -X- «•« X- X- X- -X- K X- 

* SYSTEM UT 557.34 SYSTEM (45 /:i21.82 *

* SYSTEM SERIES MTBF MRS. ?24 AV SYSTEM COST 27108 *

•X X H- X W- -X- » » « K * * X- X- «•« » » -X -X- «• X X- X- -X- -X- * -X- * -X- *• * -X- # «•« * * •«• # * * * * * * * -X- -X- X- «• X W X- * •» -X- « * X- if- X- X- X- X 

6-19
Ford Aerospace &

Communications Corporation

Table 6.3-8

Cost Of Ku-band Non-U.S. Payload For Scenario VI-B

INPUT FILENAME: CPPS10M 19-JUN-85 20:50

(185147) ESCALATION F

PROGRAM COST<* 1000) DEVELOPMENT PRODUCTION

RCVR, 14/4GHZ, SCENARIO VI-B, KU--BAND NON-CONUS HUNTER MA

TOTAL COST ~ 239.

RCVR, 14/11 (3HZ HUNTER MAY 85

TOTAL COST - 239.

MUX, INPUT 36 MHZ, 11GHZ, 6 CHAN HUNTER MAY 85

TOTAL COST ~ 543.

MUX, INPUT,36 MHZ, 11 GHZ, 2 CHAN

TOTAL COST - 148.

MATRIX, REDUNDANCY SWITCH, 5/4, 11 GHZ, COAX HUNTER MAY 8

TOTAL COST - 88.

UPCONVERTER, 4/11 GHZ HUNTER MAY 85

TOTAL COST - 775.

SSPA, 11 GHZ, 20U HUNTER MAY 85

TOTAL COST - 2748.

SSPA, 11 GHZ, 10W HUNTER MAY 85

TOTAL COST - 551.

SSPA, 11 GHZ, 5U HUNTER MAY 85

TOTAL COST - 1349.

MUX, OUTPUT, 11 GHZ, 2 CHAN, 36 MHZ

TOTAL COST - 165.

MUX, OUTPUT, 11 GHZ, 12 CHAN, 36 MHZ

TOTAL COST - 1382.

FILTER, HARMONIC, 11 GHZ, 30U, 278424-02 I-V LIMBURG 6-04

TOTAL COST - 15.

FILTER, PRESELECT, 14 GHZ, UG, 278419-01». I-V LIMBURG 6/04/

TOTAL COST - 18.

SWITCH, SPOT, 14 GHZ, UG, 278397-05 I-V LIMBURG 6/02/85

TOTAL COST - 49.

SWITCH, XFER, UG, 14 GHZ, 10W, 278396-02 I-V LIMBURG 6/03/85

TOTAL COST - 7.

COMM CONTROL & INTERFACE, 2 EA

TOTAL COST - 200.

REFLECTOR, l.OM, ANTENNA BRAZIL (DUAL GRIDDED)

TOTAL COST - 660.

FEED. NETUORK, ANTENNA BRAZIL, VERTICAL & HORIZONTAL

TOTAL COST - 1183.

FEED NETUORK, HEX/CANADIAN, HORIZONTAL

TOTAL COST - 3306.

I & T, SCENARIO VI-B, KU-BAND, NON-US DOMESTIC AND REGIONAL

TOTAL COST 0. 1817.

I.LENAME:

TOTAL COST

239.

839.

543.

148.

88.

775.

2748.

551.

1349.

165.

1383.

15.

18.

49.

7.

200.

660.

1183.

3506.

I !:< 1 7.

6-20
Ford Aerospace &

Communications Corporation ORIGINAL PAGE IS

Of POOR QUALITY

Table 6.3-8 (Continued)

Cost Of Ku-band Non-U.S. Payload For Scenario VI-B

INPUT FILENAMES CPPS10M 19-JUN-85 30:50

<185147) ESCALATION FILENAME:

TOTAL COST, WITH INTEGRATION COST

PROGRAM COST<$ 1000) DEVELOPMENT

ENGINEERING

DRAFTING 0.

DESIGN 0.

SYSTEMS 0.

PROJ MGMT 0.

DATA

SUBTOTAL<ENG)

MANUFACTURING

PRODUCTION

PROTOTYPE

TOOL-TEST Ett

PURCH ITEMS

SUBTOTAL CMFG)

COST

TOTAL COST

RANGES

FROM

CENTER

TO

0.

0.

0.

0.

0.

0.

0.

DEVELOPMENT

0.

0.

0.

PRODUCTION

534.

9766.

1408.

701.

5409.

9524.

0.

750.

10274.

15683.

PRODUCTION

.14679.

15683.

16453.

TOTAL COST

534.

2766.

0.

1408.

701.

5409.

9524.

0.

0.

750.

10274.

1.5683.

TOTAL COST

14679.

15603.

16453.

•»« M-X-ttK-H •»»*»» XHKX-K-X-ttX-X- X WX K-#X X-X-X-* X * X X » XX-W X XXX- «X X X-XX-X X X-X-X X K-X X X X X X *X XX K-K X X-

* SYSTEM UT 211.16 SYSTEM US 195.SB *

« SYSTEM SERIES MTBF HRS. 1580 AV SYSTEM COST 15683 *

X^X****X**K****WXXX-X*XX*XXXX*XX*X*KXXM*X^ XXX )<*#

6-21
Ford Aerospace &

Communications Corporation

Table 6.3-9

Cost Of Ku-band FSS Payload For Scenario II

INPUT FILENAME: CPPS5M 19--JUN--85 20:42

(185147) ESCALATION FILENAME:

PROGRAM COST<$ 1000) DEVELOPMENT PRODUCTION TOTAL CC

RCVR, 14/11GHZ, SCENARIO II, KU BAND FSS HUNTER MAY 85

TOTAL COST - 23V. 239.

MUX, INPUT, 8 CHAN, 54 MHZ, SCENARIO II, KU-BAND FSS HUNTER

TOTAL. COST - 923. 923.

MATRIX, BEAM SWITCHING, 3X3, 8 EA

TOTAL COST - 400. 400.

DRIVER AMPLIFIER, VARIABLE GAIN, 11 GHZ

TOTAL COST - 518. 518.

TUTA, 11GHZ, SOU, SCEN II, KU-BAND, FSS HUNTER MAY 85

TOTAL COST - 7800. 7800.

MUX, OUTPUT, 8 CHAN, 54MHZ, SCEN II, KU--BAND FSS, HUNTER

TOTAL COST - 986.

MATRIX, REDUND SW (RING) 5/4, COAX, HUNTER/EDRIDGE MAY85

TOTAL COST - 1.1.5.

MATRIX, REDUND SU (RING) 5/4r UG, HUNTER/EDRIDGE MAY85

TOTAL COST - 392.

FILTER, HARMONIC, 11 GHZ, 30U, 278424 1-V LIMBURG 6--04- 8

TOTAL COST -- 89.

FILTER, PRESELECT, 11 GHZ, UG, 278419, I--V LIMBURG 6/04/85

TOTAL COST -- 14.

SWITCH, SPOT, UG, 278397, I-V LIMBURG A/02/85

TOTAL COST -- 25.

SWITCH, SPOT, COAX, 278395, I-V LIMBURG 67/05/85

TOTAL COST - 13.

COMM CONTROL & INTERFACE

TOTAL COST - 200.

SWITCH, XFER, SPOT, WG, 11 GHZ, 10W, 278396

TOTAL COST -- 4.

SWITCH, XFER, COAX, 278399, I-V

TOTAL COST -- 2.

FEED, ANT VERT £ HOR,

TOTAL COST - 982.

REFLECTOR, ANTENNA 4.0M (DUAL GRID),

TOTAL COST - 990.

I & T, SCENARIO II, KU-BAND FSS HUNTER MAY 85

TOTAL COST 0. 1498.

6-22
Ford Aerospace &

Communications Corporation

Table 6.3-9 (Continued)

Cost Of Ku-band FSS Payload For Scenario II

INPUT FILENAME: CPPS5M 19--JUN-B5 20:42

(185147) ESCALATION FILENAME:

TOTAL COST, UITH INTEGRATION COST

PROGRAM COST<$ 1000)

ENGINEERING

DRAFTING

DESIGN

SYSTEMS

PRGJ MGMT

DATA

SLIBTOTAL(ENG)

MANUFACTURING

PRODUCTION

PROTOTYPE

TOOL-TEST Etf

PURCH ITEMS

SUB TOTAL<MEG)

COS

TOTAL COST

RANGES

FROM

CENTER

TO

DEVELOPMENT

0.

0.

0.

0.

0.

0.

0.

0.

0.

0.

0.

DEVELOPMENT

0.

0.

0.

PRODUCTION

240.

1187.

623.

311.

2361.

3892.

0.

8936.

12828.'

15189.

PRODUCTION

14752.

15189.

15546.

TOTAL COST

240.

1187.

0.

623.

311.

2361.

3892.

0.

0.

8936.

12828.

15189.

TOTAL COST

14752.

15189.

15546.

* SYSTEM UT

* SYSTEM SERIES MTBF MRS

247.91

522

SYSTEM US

AV SYSTEM COST

242.. 17 *

15189 *

6-23
Ford Aerospace &

Communications Corporation

Table 6.3-10

Cost Of Ku-band FSS Payload For Scenario IV

INPUT FILENAME: CPPS7M 16-JUN-85 17:3?

(185147') ESCALATION F

M

PROGRAM COST(* 1000) DEVELOPMENT PRODUCTION

RCVR, 14/4GHZ, SCEN IV, KU-BAND FSS HUNTER MAY 85

TOTAL COST - 250.

MUX,INPUT, 16 CHAN, 24MHZ, SCEN IV, KU-BAND, DBS HUNTER

TOTAL COST - 1371.

MATRIX, BEAM SWITCHING, 7X7, 8 EA

TOTAL COST - 750.

MATRIX, REDUND SW (RING) 5/4, COAX, HUNTER/EDRIDGE MAY85

TOTAL COST - 171.

UPCONVERTER (+VGAS), 4/11 GHZ, SCEN IV, KU-BAND FSS HUNTER

TOTAL COST - 1295.

TWTA, 12GHZ, SOW, SCEN IV, KU-BAND FSS HUNTER MAY 85

TOTAL COST - 13200,.

MATRIX, REDUND SW (RING) 5/4, COAX, HUNTER/EDRIDGE MAY85

TOTAL COST ' - 373.

MUX,OUTPUT, 16 CHAN, 24GHZ-11GHZ, SCEN IV, KU-BAND FSS HUNT

TOTAL COST - 3148.

FILTER, HARMONIC, 11 GHZ, SOW, 278424-02 I-V LIMBURG 6-04

TOTAL COST - 178.

FILTER, PRESELECT, 11 GHZ, UG, 278419-01, I-V LIMBURG 6/04/

TOTAL COST - 14.

SWITCH, SPDT, UG, 278397-05 I-V LIMBURG 6/02/85

TOTAL COST - 25.

SWITCH, XFER, SPDT, UG, 17 OR 14 GHZ, 10U, 278396-02 I-V LIM

TOTAL COST

SWITCH, XFER, COAX, 278399-02 I-V

TOTAL COST

LIMBURG

4.

6/05/85

2.

SWITCH, SPDT, COAX, 278395-XX I-V LIMBURG 6/05/85

TOTAL COST - . 13.

COMM CONTROL & INTERFACE, 2 EA

TOTAL COST

FEED, ANT, VERT & HOR, SCEN IV, KU-BAND FSS

TOTAL. COST

REFLECTOR, ANT(DUAL GRID), 4.0M, SCEN IV, KU-BAND FSS HUNT

TOTAL COST -• 990..

I ?. T, SCENARIO IV, KU-BAND FSS HUNTER MAY 85

TOTAL COST 0. 2718.

200.

HUNTER MAY 85

3994.

ILENAME:

TOTAL. COST

250,

1371.

750.

171.

1295.

13200.

373.

3148.

' 178.

14.

25.

4.

a.

13.

200.

3994.

990.

2718.

6-24
Ford Aerospace &

Communications Corporation

ORIGINAL PAGE IS

OF POOR QUALITY

Table 6.3-10 (Continued)

Cost Of Ku-band FSS Payload For Scenario IV

INPUT FILENAME: CPPS7M 16-JUN-85 17:39

C185147) ESCALATION FILENAME:

TOTAL COST, WITH INTEGRATION COST

PROGRAM COSTC* 1.000)

ENGINEERING

DRAFTING

DESIGN

SYSTEMS

PROJ MGMT

DATA

SUBTOTAL(ENG)

MANUFACTURING

PRODUCTION

PROTOTYPE

TOOL-TEST EQ

PURCH- ITEMS

SUBTOTAL(MFC)

TOTAL COST

COST RANGES

FROM

CENTER

TO

DEVELOPMENT

0.

0.

0.

0.

0.

0.

0,

0.

0.

0.

0.

DEVELOPMENT

0.

0.

0.

PRODUCTION

457.

2343.

1245.

615.

4660.

9609.

0.

14435.

24035..

28695.

PRODUCTION

27696,,

28695.

29463,

TOTAL COST

457.

2343.

0.

1245.

615.

4660.

9609.

0.

14425.

24035.

28695.

TOTAL COST

27696.

28695.

P 9 4;'. R „

W «- X- «• •"• X- X- * * * * X- » W * X X- * W «• X- •*• X- K X- K X- «• X- -X- «• «• * tt «• «•»-X- X- X- X- X- # X- # X- «• K X- * X- X- X- X- X- X- X- X- X- * •» X- -

* SYSTEM UT 601.51 SYSTEM US 571.07 *

* SYSTEM SERIES MTBF MRS. 293 . AV SYSTEM COST 28695 *

X- X- -X- X- •«• «• -X- * * * > «• •» *• X- X- X- X- * X X- * * -X- * *• «• * -X-»-X- •» «• * * * -X- * X- •» -X- * * X- X- X- -X X- X- X- W X- » ¥ ft M- W X- X X -X- > X- •

6-25
Ford Aerospace.•&

Communications Corporation

Table 6.3-11

Cost of Ku-band FSS Payload for Scenarios V, VI-A and 'VI-B

INPUT FILENAME: CPPS9M

PROGRAM COST ($ 1000)

24-JUL-85 19:57

(185147)

DEVELOPMENT

ESCALATION -FILENAME:

PRODUCTION TOTAL COST

RECEIVER, 14/11 GHZ, 18EA; SCENARIO V, VI-A & B, KU-BAND FSS

TOTAL COST 0. 483. 483.

MUX, INPUT, 12 CHAN, 11GHZ, 36GHZ, 9EA

TOTAL COST 0. 3149. 3149.

MATRIX, BEAM SWITCHING, 9X9,12EA

TOTAL COST 0. 2400. 2400.

MATRIX, REDUND SWITCH, 5/4, 11 GHZ, COAX, 27 EA

TOTAL COST " Q. 341. 341.

COMM CONTROL & INTERFACE, 2 EA

TOTAL COST 0. 200. 200.

SSPA, 11GHZ, 2W, (+2 VGAS), 135EA

TOTAL COST 0. 10615. 10615.

MATRIX, REDUNDANCY SWITCH, 5/4, ll'GHZ WG, (RING), 27EA

TOTAL COST 0. 320. 320.

MUX, OUTPUT, 12 CHANNEL, 36MHZ, 9EA

TOTAL COST 0. 3308. 3308.

FILTER, HARMONIC, DWG 278423, 9EA

TOTAL COST 0. 42. 42.

FILTER, PRESELECT, DWG 278420-03 , 9EA

TOTAL COST 0. 36. 36.

SWITCH, WG, 14,GHZ, DWG 278397-05, 9EA

TOTAL COST 0. 74. 74.

SWITCH, XFER, WG, 14 GHZ, 10W, DWG 278396, 4EA

TOTAL COST 0- 14. 14.

SWITCH, XFER, COAX, DWG 278399, 4EA

TOTAL COST 0. 6. 6.

SWITCH, SPOT, COAX, 11 GHZ, DWG 278395, 9EA

TOTAL COST 0. 40. 40.

REFLECTOR, ANT. DUAL GRID, 4.6M, 1EA

TOTAL COST 0. 1100. 1100.

FEED NETWORK, VERTICAL & HORIZONTAL, 2EA

TOTAL COST 0. - 5730. 5730.

I & T SCENARIO V, VI-A & B

TOTAL COST Q. 4156. 4156.

6-26
Ford Aerospace &

Communications Corporation

Table 6.3-11 (Continued)

Cost of Ku-Band FSS Payload for Scenarios V. VI-A and VI-B

INPUT FILENAME: CPPS9M 24-JUL-85 19:57

(185147) ESCALATION FILENAME:

TOTAL COST, WITH INTEGRATION COST

PROGRAM COST ($.1000) DEVELOPMENT

ENGINEERING

DRAFTING

DESIGN

SYSTEMS

PROJ MGMT

DATA

SUBTOTAL(ENG)

MANUFACTURING

PRODUCTION

PROTOTYPE

TOOL - TEST EQ

PURCH ITEMS

SUBTOTAL(MFG)

TOTAL COST

PRODUCTION TOTAL COST

0.

0.

0.

0.

0".

0.

m

0.

0.

0.

0.

631.

3240.

2082.

1014.

6967 .

23735.

-

0.

1312 .

25047 .

631

3240

0

2082

1014

6967

23735

0

0

1312

25047

32014 32014

COST RANGES DEVELOPMENT PRODUCTION TOTAL COST

o

o

FROM

CENTER

TO

SYSTEM WT

SYSTEM SERIES MTBF HRS .

0.

0.

0.

597.15

716

29576.

32014.

33873

SYSTEM WS

AV SYSTEM

29576.

32014.

33873.

565.01

COST 32014

6-27
Aerospace &

Communications Corporation

Table 6.3-12

Cost Of Ku-band DBS Payload For Scenario II

INPUT FILENAME: CPPS6M 18-JUN-85 17:34

(185147) ESCALATION FILENAME:

PROGRAM COST/* 1000) DEVELOPMENT PRODUCTION TOTAL COST

RCVR, 17/4GHZ, SCENARIO II, KU-BAND DBS HUNTER MAY 85

TOTAL COST - 194. 194.

MUX,INPUT, 8 CHAN, 24MHZ, SCEN II, KU-BAND, DBS HUNTER MA

TOTAL COST - 688. 688.

MATRIX, BEAM SUITCHING, 2X2, 8 EA

TOTAL COST - 360. 360.

MATRIX, REDUND SU (RING) 5/4, COAX, HUNTER/EDRIDGE MAY85

TOTAL COST - 91. 91.

DRVR AMP, VARI GAIN/RCVR, SCEN II, KU-BAND DBS, HUNTER MA

TOTAL COST - 908. 908.

TUTA, DBS 100U HUNTER MAY 85

TOTAL COST - 5200. 5200.

MATRIX, REDUND SU (RING) 5/4, UG, HUNTER/EDRIDGE MAY85

TOTAL COST - 304. 304.

MUX, OUTPUT, 8 CHAN, 12GHZ, SCEN II, KU-BAND DBS, HUNTER

TOTAL COST - 1033. 1.033.

FILTER, HARMONIC, 11 GHZ, 30U, 278424-02 I-V LIMBURG 6-04

TOTAL COST - 59. 59.

FILTER, PRESELECT, 11 GHZ, UG, 278419-01, I-V LIMBURG 6/04/

TOTAL COST - 9. 9.

SUITCH, SPOT, UG, 278397-05 I-V LIMBURG 6/02/85

TOTAL COST - 16. 16.

SUITCH, XFER, SPDT, UG, 11 GHZ, 10U, 278396-02 I-V LIMBURG 6

TOTAL COST - 4. 4.

SUITCH, XFER, COAX, 278399-02 I-V LIMBURG 6/05/85

TOTAL COST - 2. 2.

SUITCH, SPDT, COAX, 278395-XX I-V LIMBURG 6/05/85

TOTAL COST - 9. 9.

COMM CONTROL & INTERFACE, 2 EA

TOTAL COST - 200. 200.

FEED, ANT, SCEN II, KU-BAND DBS HUNTER MAY 85

TOTAL COST - 912. 912.

REFLECTOR, ANT, (1.8 X 1.4M), SCEN II, KU-BAND DBS HUNTER

TOTAL COST - 125. 125.

I 2, T, SCENARIO II, KU-BAND DBS HUNTER MAY 85

TOTAL COST 0. 1147. 1147.

6-28
Ford Aerospace &

Communications Corporation

Table 6.3-12 (Continued)

Cost Of Ku-band DBS Payload For Scenario II

INPUT FILENAME: CPPS6M 18-JUN-85 17:34

(185147) ESCALATION FILENAME:

TOTAL COST, UITH INTEGRATION COST

PROGRAM COST<* 1000) DEVELOPMENT

ENGINEERING

DRAFTING 0.

DESIGN 0.

SYSTEMS 0.

PROJ MGMT 0.

DATA

SUBTOTAL(ENG)

MANUFACTURING

PRODUCTION

PROTOTYPE

TOOL-TEST EQ

PURCH ITEMS

SUBTOTAL(MFG)

TOTAL COST

COST RANGES

FROM

CENTER

TO

0.

0.

0.

0.

0.

0.

0.

DEVELOPMENT

0.

0.

0.

PRODUCTION

251.

1231.

615.

308.

2405.

3433.

0..

5424.

8857.

11262.

PRODUCTION

10871.

11262.

11587.

TOTAL COST

251.

1331.

0.

61.5.

308.

2 40 5.

3433.

0.

0.

8857.

1.1.262.

TOTAL COST

10871.

11262.

1158*7.

* SYSTEM UT 224.18

* SYSTEM SERIES MTBF HRS. 790

[•********* ******

SYSTEM US 218.74 *

AV SYSTEM COST 11262 *

:• * ****** * * * * * *

6-29
Aerospace &

Communications Corporation

Table 6.3-13

Cost Of Ku-band DBS Payload For Scenario IV

INPUT FILENAME: CPPS8M 16-JUN-85 17:40

(185147) ESCALATION F

PRODUCTION

HUNTER MAY 85

989.

PROGRAM COST($ 1000) DEVELOPMENT

RCVR, 17/4 GHZ, SCENARIO IV, KU-BAND DBS

TOTAL COST

MUX, INPUT, 16 CHAN, A GHZ, 34MHZ

TOTAL COST - 1706.

MATRIX, REDUND SU (RING) 5/4, COAX, HUNTER/EDRIDGE MAY85

TOTAL COST - 217.

UPCONVERTER <+VGAS>, 4/13 GHZ, SCEN IV, KU-BAND DBS HUNTER

TOTAL COST - 1616.

MATRIX, REDUND SU (RING) 5/4, UIG, HUNTER/EDR IDGE MAY85

TOTAL COST - 1957.

TUTA, 11GHZ, 300U, SCEN IV, KU-BAND DBS HUNTER MAY 85

TOTAL COST - 34000.

MUX, OUTPUT, 16 CHAN, 94 GHZ, 19GHZ

TOTAL COST - 3945.

FILTER, HARMONIC, 11 GHZ, 30U, 978494-09 I-V LIMBURG 6-04

TOTAL COST - . . 338.

FILTER, PRESELECT, .11 GHZ, UG, 378419-01, I-V. LIMBURG 6/04/

TOTAL COST - 18.

SUITCH, SPOT, UG, 978397-05 I-V LIMBURG 6/03/35

TOTAL COST - 33.

SUITCH, XFER, SPDT, UG, 17 GHZ, 10U

TOTAL COST - 7.

SUITCH, XFER, COAX, 978399-03 I-V LIMBURG 6/05/85

TOTAL COST - 3.

SUITCH, SPDT, COAX, 378395-XX I-V LIMBURG 6/05/85

HUNTER

TOTAL COST

C.OMM CONTROL & INTERFACE, 9 EA

TOTAL COST

FEED, TX NETWORK, SCEN IV, KU-BAND DBS

TOTAL COST

REFL, ANT, TX, 9.5M, HUNTER MAY 85

TOTAL COST

FEED, RX NETWORK, SCEN IV. KU-BAND DBS

TOTAL COST

REFLECTOR, ANTENNA, RX, 1. 9M

TOTAL COST

I ?r T, SCENARIO IV, KU-BAND DBS HUNT MAY 85

TOTAL COST 0.

18.,

300.

MAY 85

455.

350.

HUNTER MAY 85

877.

300.

3167.

I LENAME:

TOTAL COST

383.

1.706.

217.

1.616.

1.257.

34000.

3945.

338.

.1.8.

33.

7.

3.

18.

300.

. 455.

350.

377.

200 „

3167.

6-30
Ford Aerospace &

Communications Corporation

Table 6.3-13 (Continued)

Cost Of Ku-band DBS Payload For Scenacio IV

INPUT FILENAME: CPPS8M 16-JUN-85 17:41

(185147) ESCALATION FILENAME:

TOTAL COST, UITH INTEGRATION COST

PROGRAM COST(* 1000) DEVELOPMENT

ENGINEERING

DRAFTING 0.

DESIGN 0.

SYSTEMS 0.

PROJ MGMT 0.

DATA

SUBTOTAL(ENG)

MANUFACTURING

PRODUCTION

PROTOTYPE

TOOL-TEST EQ

PURCH ITEMS

SUBTOTAL(MFG)

TOTAL COST

COST RANGES

FROM

CENTER

TO

0.

0.

0.

0.

6. .

o.

On

DEVELOPMENT

0.

0.

0.

PRODUCTION

433.

9180.

1155.

570.

4337.

0.

34767.

34151.

33488.

PRODUCTION

37493.

38488.

39381.

TOTAL. COST

433.

3180.

0.

1155.

570.

4337.

9383.

0.

0.

24767.

34.1.51.

38488.

TOTAL COST

37493.

38488.

39381.

* X- X- -X- X X- X- -X- X-«' * X- -X- X- w- v- w- * » X X X- X- X- * * X- X- W X X- X- X- X- X- X- -X- X- X- *• X: X- X- « «• X- X- X- X- X- X W X- X- * «• X- X- K X- X

x SYSTEM UT 995.56 SYSTEM US 957.34 -v

x- SYSTEM SERIES MTBF I-IRS. 311 AV SYSTEM COST 384S8 •«

X-» -X- * * X- X- X- -X- * * * X-» X- X- X- X- X- X- # «• » X- * * * * •» •«• X- * X- «• -X- -X- •» -X- X- » X X- •» -X- * X- X- X- «• X- -X- X- -X- •» * -X -X- X- » «• X- 

6-31
Ford Aerospace &

Communications Corporation

Table 6.3-14

INPUT FILENAME: CPPS11M 16-JUN-85 17:45

(185117)

PROGRAM COST(* 1000) DEVELOPMENT P

RECEIVER, 30/4 GHZ,. SCENARIO II, V, & VI-A&B,

TOTAL COST

MUX. INPUT 5 CHANNEL

TOTAL COST

MUX, INPUT, 3 CHANNEL

TOTAL COST

MUX, INPUT, 2 CHANNEL

TOTAL COST

MUX, INPUT 1 CHANNEL

TOTAL. COST

MATRIX, BEAM SWITCHING, 6X6, i EA

TOTAL COST

MATRIX, BEAM SWITCHING, 7X7, 2 EA

TOTAL COST

MATRIX,. BEAM SWITCHING, 22X32 (DYNAMIC).. 1 EA

TOTAL COST

UPCONVERTER, CHANNEL 1, 4/20 GHZ

TOTAL COST

UPCONVERTER, CHANNEL 2, 4/20 GHZ

TOTAL COST

UPCONVERTER, CHANNEL 3, 4/20 GHZ

TOTAL COST

UPCONVERTER, CHANNEL. 4, 4/20 GHZ

TOTAL COST

UPCONVERTER, CHANNEL 5, 4/20 GHZ

TOTAL COST

SWITCH MATRIX, 5/4 REDUNDANCY (RING) COAX

TOTAL COST

SWITCH MATRIX, 7/5 REDUNDANCY (RING) COAX

TOTAL COST

SWITCH MATRIX, 5/4 REDUNDANCY (RING) W/G

TOTAL COST

SWITCH MATRIX, 7/5 REDUCNDANCY (RING) W/G

TOTAL COST

MUX, OUTPUT 5 CHANNEL

TOTAL COST

MUX, OUTPUT 3 CHANNEL

TOTAL. COST

MUX, OUTPUT 2 CHANNEL

TOTAL. COST

MUX, OUTPUT 1 CHANNEL

TOTAL COST

HARMONIC FILTERTOTAL COST

PRESELECT FILTER

TOTAL COST

6-32

ESCALATION

RODUCTION

KA--I3AND FSS

747.

396.

179.

506. .

309.

75.

150.

100.

215.

324.

334.

33 4 .

.

764.

140.

90.

155.

97.

334.

152.

423.

259.

74.

92.

n , rung v j. — o

FILENAMES

TOTAL COS

747.

396TM

179.

506.

309.

75.

150.

100 .

21.5.

324.

324.

324.

764,.

1 40 .

90.

155.

97.

334.

152.

423.

259.

74.

92.
Ford Aerospace &

Communications Corporation ORIGINAL PAGE IS

OF POOR QUALITY

Table 6.3-14 (Continued)

Cost Of Ka-band FSS Payload For Scenarios II. V. VI-A. And VI-B

INPUT FILENAME: CPPS11M 16-JUN-85 17:45

(185147) ESCALATION FILENAME:

SPOT SWITCH W/G 30 GHZ

TOTAL COST - 1A5.

TRANSFER SWITCH W/G 30 GHZ

TOTAL COST - 36.

SPOT SWITCH COAX 4 GHZ

TOTAL COST . _ 88.

TRANSFER SWITCH COAX 4 GHZ

TOTAL COST - -15 .

TWTA 20 GHZ 30W AVE.

TOTAL COST - 11.370.

COMM CONTROL f. INTERFACE, 2 EA

TOTAL COST - 200.

I & T, SCENARIO II, V, & VI--A & B, KA-BAND FSS HUNTER

TOTAL COST 0. 1951.

MAY

165.

36.

80.

15.

.1.1270.

300.

1951.

INPUT FILENAME: CPPS11M 16-JUN-85 17:45

(185147) E S C A L A T10 N F11... E N A H E;

TOTAL COST, WITH INTEGRATION COST

PROGRAM COSTC* 1.000)

ENGINEERING

DRAFTING

DESIGN

SYSTEMS

PROJ MGMT

DATA

SUB TOTAL(ENG)

DEVELOPMENT

0.

0.

0.

0.

0.

0.

PRODUCTION

379.

1766.

888.

448.

3481.

TOTAL. COST

379.

1.766.

c i o

888.

3481.

MANUFACTURING

PRODUCTION

PROTOTYPE

TOOL--TEST EQ

PURCH ITEMS

SUB TOTAL(MFC)

TOTAL COST

COST RANGES

FROM

CENTER

TO

-

0 .

"0.

0.

0.

4737.

-

0.

11.741.

1.6473.

4737.

0 .

0.

1.1741..

.1.6478.,

0.

DEVELOPMEN"

0.

0.

0.

19958..

PRODUCTION

19404.

1.9958.

20449.

19958.

TOTAL COS

1.9404.

19958.

20142.

6-33
Ford Aerospace &

Communications Corporation

Table 6.3-15

Cost Of Ka-band Scan Pavload For Scenarios II. V. VI-A. And VI-B

INPUT FILENAME: CPPS12M 18-JUN-85 22:14

(185147) ESCALATION FILENAME:

PROGRAM C03T($ 1000) DEVELOPMENT

RCYR, 30/4 GHZ SCENARIO II, V, UI-AKB, KA-BAND SCAN

TOTAL COST

MUX, INPUT 5 CHANNEL

TOTAL COST

MUX, INPUT 6 CHANNEL

TOTAL COST

BASEBAND PROCESSOR, 1EA

TOTAL COST

REDUNDANCY SWITCH MATRIX, 5/4, (RING) COAX

TOTAL COST

UPCONVERTER (+VGAX)

TOTAL COST

TUTA 20 GHZ 15U £ 30U

TOTAL COST

OUTPUT MULTIPLEXER 5 CHANNEL

TOTAL COST

OUTPUT MULTIPLEXER 6 CHANNEL

TOTAL COST

REDUNDANCY SUITCH MATRIX, 5/4 (RING) COAX

TOTAL COST

HARMONIC FILTER

TOTAL COST

PRESELECT FILTER

TOTAL COST

SPOT SUITCH 30 GHZ W/G

TOTAL COST

TRANSFER SUITCH 30 GHZ U/G

TOTAL COST

TRANSFER SUITCH 4 GHZ COAX

TOTAL COST

SPOT SUITCH 4 GHZ COAX

TOTAL COST

PROGRAMMABLE FREQUENCY SHIFTER

TOTAL COST

COMM CONTROL 2, INTERFACE, 2 EA

TOTAL COST

MATRIX, DYNAMIC SUITCH, 4 GHZ, 20X20, 1 EA

TOTAL COST

ANTENNA REFLECTORS (2 MAIN 2, 2 SUB), l.OM

TOTAL COST

ANTENNA FEED NETWORK (1 RX + 1 TX>

TOTAL. COST

I & T, SCENARIO IT, V, VI-A2.B, KA-BAND SCAN

TOTAL. COST 0.

RODUCTION

SCAN HUNTER

337.

643.

460.

7000.

153.

1026.

9200.

525.

839.

170.

119.

29.

49.

11.

5.

26.

. 250.

200.

95.

3000.

3497.

HUNTER MAY 85

2485.

TOTAL COST

337.

643.

460.

7000.

153.

1026.

9200.

525.

839.

170.

119.

28.

49.

11.

5.

26.

250.

200.

95.

3000.

3497.

2 49 5.

6-34
Ford Aerospace &

Communications Corporation

Table 6.3-15 (Continued)

Cost Of Ka-band Scan Payload For Scenarios II. V. VI-A. And VI-B

INPUT FILENAME: CPPS12M 18-JUN-85 22:14

(185147) ESCALATION FILENAME:

TOTAL COST, UITH INTEGRATION COST

PROGRAM CQST<* 1000)

ENGINEERING

DRAFTING

DESIGN

SYSTEMS

PROJ MGMT

DATA

SUBTOTAL<ENG)

MANUFACTURING

PRODUCTION

PROTOTYPE

TOOL -TEST EQ

PURCH ITEMS

SUBTOTAL(MFG)

TOTAL COST

DEVELOPMENT

0.

0.

0.

0.

0.

0.

0.

0.

0.

0.

0.

PRODUCTION

900.

4201.

1781.

887.

7768.

9910.

0.

12438.

22348.

30116.

TOTAL COST

900.

4201.

0.

1781.

887.

7768.

9910.

0.

0.

12438.

22348.

30116.

COST RANGES

FROM

CENTER

TO

DEVELOPMENT

0.

0.

0.

PRODUCTION

28967.

30116.

31145.

TOTAL COST

28967.

30116.

31145.

* * W * * * * * * * * * * * * * * * X * * * * X * * * * * * M- * * » tt * * * * K ft «• * * * * * # tt * * * * «• * K X 

* SYSTEM UT 1021.49 SYSTEM US 973.17 *

* SYSTEM SERIES MTBF HRS. 358 AV SYSTEM COST 30116 *

********************************** x****x *#****** w******x•« #** #* *****»*:•<

6-35
Ford Aerospace &

Communications Corporation

Table 6.3-16A

Cost Of 60 GHz ISL Pavload For Scenario VI-A

INPUT FILENAME: CPPS15M 18-JUN-85 20:55

(185147) ESCALATION FILENAME::

PROGRAM COST(* 1000) DEVELOPMENT PRODUCTION TOTAL COST

RECEIVER, SCENARIO VI-A, 60 GHZ, ISL, HUNTER MAY 85

TOTAL COST - 351. 351.

DIPLEXER, 60 GHZ, ISL

TOTAL COST - 100. 100.

CPU/PROCESSOR, 60 GHZ, ISL

TOTAL COST -- 800. 800.

GIMBALS, 60 GHZ, ISL

TOTAL COST - 360. 360.

DRIVE ELECTRONICS, 60 GHZ, ISL

TOTAL COST - 240. 240.

TRANSMITTER, 5 U, IMPATT, 60 GHZ, ISL

TOTAL COST - 1800. 1800.

ANTENNA ASSY (REFL, SUB-REFL, FEED ?, SUPPORT), 3.0M, 60 GHZ,

TOTAL COST - 700. 700.

I & T, SCENARIO VI-A, 60 GHZ, ISL

TOTAL COST 0. 782. 789.

6-36
Ford

 Aerospace &

Communications Corporation

Table 6.3-16A (Continued)

Cost Of 60 GHz ISL Payload For Scenario VI-A

INPUT FILENAME: CPP515M 18-JUN-85 20:55

(185147)' ESCALATION FILENAME:

TOTAL COST, WITH INTEGRATION COST

PROGRAM COST<* 1000) DEVELOPMENT

ENGINEERING

DRAFTING 0.

DESIGN 0.

SYSTEMS 0.

PROJ MGMT 0.

DATA

SUBTOTAL(ENG)

0.

0.

PRODUCTION

289.

1362.

760.

414.

2824.

TOTAL COST

289.

1362.

0.

760.

414.

2824.

MANUFACTURING

PRODUCTION

PROTOTYPE

TOOL-TEST EO

PURCH ITEMS

SUBTOTAL(MFG)

TOTAL COST

0.

0.

0.

0.

0.

2082.

226.

0.

2308.

5132.

2082.

0.

226.

0.

2308.

5132.

COST RANGES

FROM

CENTER

TO

DEVELOPMENT

0.

0.

0.

PRODUCTION

4821.

5132.

5394.

TOTAL COST

4821.

5132.

5394.

HX************************************************************************

* SYSTEM UT 122.40 SYSTEM US 118.60 ;

* SYSTEM SERIES MT8F HRS. 6824 AV SYSTEM COST 5132 *

[ * * * * ********* -K *****••

6-37
Ford Aerospace &

Communications Corporation

Table 6.3-16B

Cost Of 60 GHz ISL Payload For Scenario VI-B

INPUT FILENAME: CPPS16M 13-JUN-85 21:19

(185147) ESCALATION FILENAME:

PROGRAM COST<* 1000) DEVELOPMENT PRODUCTION TOTAL COST

RECEIVER, SCENARIO VI-B, 60 GHZ, ISL, HUNTER MAY 85

TOTAL COST - 297. 297.

DIPLEXER, 60 GHZ, ISL

TOTAL COST - 100. 100.

CPU/PROCESSOR, 60 GHZ, ISL

TOTAL COST - 300. 300.

GIMBALS, 60 GHZ, ISL

TOTAL COST - 360. 360.

DRIVE ELECTRONICS, 60 GHZ, ISL

TOTAL COST • 240. 240.

TRANSMITTER, 5 U, IMPATT, 60 GHZ, ISL

TOTAL COST - 1200. 1200.

ANTENNA ASSY (REFL, SUB-REFL, FEED & SUPPORT), 3.0M, 60 GHZ,

TOTAL COST - 700. 700.

I 2, T, SCENARIO VI-B, 60 GHZ, ISL.

TOTAL COST 0. 600. 600.

6-38
Ford Aerospace &

Communications Corporation

Table 6.3-16B (Continued)

Cost Of 60 GHz ISL Payload For Scenario VI-B

INPUT FILENAME: CPPS16M 18-JUN-85 21:19

(185147) ESCALATION FILENAME:

TOTAL COST, UITH INTEGRATION COST

PROGRAM COST<* 1000) DEVELOPMENT

ENGINEERING

DRAFTING 0.

DESIGN 0.

SYSTEMS 0.

PROJ MGMT 0.

DATA

SUBTOTAL(ENG)

MANUFACTURING

PRODUCTION

PROTOTYPE

TOOL -TEST EG? .

PURCH ITEMS

SUBTOTAL(MFG)

TOTAL COST

COST RANGES

FROM

CENTER

TO

0.

0.

0.

0.

0.

0.

0.

DEVELOPMENT

0.

0.

0.

PRODUCTION

261.

1226.

670.

368.

2526.

1601.

170.

0.

1771.

4297.

PRODUCTION

4058.

4297.

4501.

TOTAL COST

261.

1236.

0.

670.

368.

2526.

1601.

0.

170.

0.

1771.

4297.

TOTAL COST

4058.

4297.

4501.

* SYSTEM UT 1.1.6.40 SYSTEM US 11.3.20

* SYSTEM SERIES MTBF HRS. 6891 AV SYSTEM COST 4297

**************************WX ******* a-************.**************** XX****** X W

6-39
Ford Aerospace &

Communications Corporation

6.4 SCENARIO PAYLOAD COST

The payload costs associated with each of the five payload

configuration scenarios is summarized in Table 6.4-1. It is

also to be noted that the costs are for "recurring" units and do

not include pro-rata share of development costs.

The costs of each of the payload subsystems is shown to range

from $2.4 million for a C/L-band maritime package for use in

scenario VI-B up to $38.5 million for a Ku-band DBS package for

use in scenario IV.

6.5 SCENARIO PLATFORM COST

The total platform and launch costs associated with each of

the five payload configuration scenarios is summarized in Table

6.5-1. The recurring cost for each payload scenario, expressed

in 1984 dollars, is expected to range from $67 million for

scenario IV up to $132 million for scenario VI-B.

After including estimates for the platform bus and launch

costs the total is raised to $250 million for a scenario IV

platform on-orbit and to $372 million for a scenario VI-B

platform on-orbit.

6-40
Ford Aerospace &

Communications Corporation

Table 6.4-1

Proiected Costs of Payload Elements ($M)

Payload Element

C-Band. FSS

C-Band. FSS

C/L-Band Maritime

(Atlantic)

C/L-Band Maritime

(Pacific)

C-Band. Internat'l

C-Band. Non-U.S.

Ku-Band, Non-U.S.

Ku-Band. FSS

Ku-Band. FSS

Ku-Band. FSS

Ku-Band. DBS

Ku-Band. DBS

Ka-Band. FSS

Ka-Band. SCAN

60 GHz. ISL

TOTAL

§

§

§s

§

§

§

§

§

§

§

§

§

§

§

§

§

§

§

§

§

§

§

§

§

§

§

§

§

§

§

§

§

§

§

§

§s

§§

§

§

Incorporated

II § IV

§

§

4.5 §

§

§

§

§

§

§

§

§

§

§

§

§

§

§

15.2 §

§

§ 28.7

§

§

§

11.3 §

§

§ 38.5

§

'§

20.0 §

§

30.1 §

§

§

§

§

§

81.1 § 67.2

§

§

in

§

§

§

§

§

§

§

§

§

§

§

§

§

§

§

§

§

§

§

§

§

§

§

§

§

§

§

§

§

§

§

§

§

§

§

§

§

§

§

§

Following Scenarios

V § VI -A

§

§

§

§

7.9 § 7.8

§

§ 3.4

§

§

§

§ 27.8

§

§

§

§

§

§

§

§

§

§

32.0 § 32.0

§

§

§

§

§

§

20.0 § 20.0

§

30.1 § 30.1

§

§

§ 5.1

§

§

90.0 § 126.2

§

§

§ VI-B

§

§

§

§

§

§

§

§

§ 2.4

§

§

§

§ 27.1

§

§

§ 15.7

§

§

§

§

§

§ 32.0

§

§

§

§

§

§

§ 20.0

§

§ 30.1

§

§

§ 4.3

§

§

§ 131.6

§

§

§

§

§

§

§

§

§

§

§

§

§

§

§

§

§

§

§

§

§

§

§

§

§

§

§

§

§

§

§

§

§

§

§

§

§

§

§

§

§

§

§

§

6-41
Ford Aerospace &

Communications Corporation

SECTION INDEX

Page

7.0 CRITICAL TECHNOLOGY 7-1

7.1 OVERVIEW 7-1

7.2 ANTENNA TECHNOLOGY 7-1

7.2.1 Background 7-1

7.2.2 Limitations Imposed on Communications Satellite 7-3

Antennas

7.2.3 Communication Satellite Antenna Technology in 1998 7-5

7.2.3.1 Further Refinements in Existing Technology 7-6

7.2.3.2 Maturation of Current Experimental Work 7-16

7.2.3.3 New Antenna Concepts 7-20

7.2.4 Summary of Antenna Technology 7-20

7.3 RF TRANSPONDER TECHNOLOGY 7-23

7.3.1 Background 7-23

7.3.2 Power Amplifier 7-24

7.3.3 Power Combining Technigues 7-27

7.3.4 Receiver Technology 7-29

7.4 ON-BOARD PROCESSING TECHNOLOGY 7-31

7.5 PAYLOAD ON-ORBIT SERVICING TECHNOLOGY 7-35

7.6 GROUND TERMINAL TECHNOLOGY 7-38

7.6.1 Terminal Antenna Development 7-39

7.6.2 RF Subsystem Development 7-40

7.6.3 Digital Eguipment Development 7-41

7.6.4 User Interface Development 7-42

7.7 FREQUENCY RE-USE 7-43

7.8 IDENTIFICATION OF KEY TECHNOLOGY DRIVERS 7-44

7.8.1 Overall Technology 7-44

7.8.2 Component Technology 7-48

7.8.3 Support Technology 7-52
Ford

 Aerospace &

Communications Corporation

7.0 CRITICAL TECHNOLOGY (TASK 6)

7.1 OVERVIEW

The purpose of Task 6 - Critical technology is to identify

both the enabling and supporting technologies critical to the

eventual implementation and operation of each of the payload

scenarios. Items of large economic uncertainty as well as great

technical risk are highlighted. Primary inputs to this task were

based on Ford Aerospace experience gained from participation in:

o Technology demonstration programs leading up to the NASA

ACTS Program

o Hilstar technology requirements definition programs

Details of the antenna technology are presented in section

7.2. the RF transponder technology in 7.3. the on-board

processing technology in 7.4. the payload on-orbit servicing

technology in 7.5. and frequency reuse technology issues in 7.7.

A summary of key technology developments which are recommended

to support a successful implementation of a 1990's era space

communications platform is shown in Table 7.1-1. Additional

detail in presented in section 7.8.

7.2 ANTENNA TECHNOLOGY

7.2.1 Background

Communication satellite antenna technology will undergo a

significant advancement by the year 1998. This progress will be

due to enormous pressures imposed by the burgeoning growth in the

demands placed upon existing services and from a host of new

services that will become available.

7-1
Ford Aerospace &

Communications Corporation

Table 7.1-1

Key Technology Drivers

Baseband Processing

- High efficiency demod/modulators

- A to D format conversion

- High speed programmable frequency source

- Scanning and processing algorithms.

Antennas

- Dynamic beam

- Polarization tracking at Ka-Band for H and V

re-use.

- Dual polarizer for receive and transmit bands

Transponder

- High power Ku and Ka-Band SSPA's

- High speed switching at 11 and 20 GHz

- Dielectric resonator filters and oscillators

Intersatellite Links

- Optical

- RF

Support Technology

- Materials technology

- MMIC and VLSI development

- Device development: GaAs. CMOS-SOS, etc.

- Radiation hardening development

Transportation and Space Station Support

- Deployment

- Assembly

- Alignment

— Servicing

- Check-out at LEO

- Transportation to GEO

7-2
Ford Aerospace &

Communications Corporation

The increase in communications satellite traffic will place

ever-increasing burdens on the scarce orbital arc and frequency

spectrum resources. These must be used more efficiently by

continuing the great strides in the advancement of antenna

technology that have made today's systems possible and also to

make use of frequency bands that are not yet fully exploited.

Some capacity increase is still possible in the crowded 6/4 GHz

bands, but the most significant future increases will be in the

14/11 GHz and 30/20 GHz bands as well as in the 44 GHz band. In

1983 the FCC approved a U. S. Domestic DBS uplink band of 17.3

to 17.8 GHz and a downlink band of 12.2 to 12.7 GHz. Many new

services will employ frequencies that may be as low as the HF

range and as high as S-band. Other frequencies that are not

used by satellites either have not been allocated or represent

bands that are already in use for terrestrial services.

Eventually, these bands may also come into use for special

satellite services.

The geostationary platform offers a solution that will

alleviate the problems of orbital arc congestion and saturation

of the available frequency spectrum by making it possible to

place many high-performance antennas operating over several

frequency bands at a single orbital location. Onboard signal

processing will allow interconnections between all frequency

bands. Several such platforms would be interconnected through

intersatellite links. Severe pressure will be placed upon the

antenna designs to make the maximum use of these platforms.

7.2.2 Limitations Imposed on Communications Satellite Antennas

Before the specific advancements in communications antenna

technology can be predicted, it is necessary to consider their

limitations. The performance capabilities of current

communications satellite antennas are restricted by both

inherent and external factors. The inherent factors have to do

7-3
Ford Aerospace &

Communications Corporation

with physical limitations and restrictions that are dictated by

the current technology. For a given size and configuration,

gain is limited by the physical capture area of the aperture, by

losses within the feed system, and by dimensional deviations.

Likewise, polarization and sidelobe isolation levels are

dependent upon available feeds and polarizers and on antenna

dimensional stability. In the case of shaped-beam and multibeam

antennas, performance is also limited by the size and degree of

complexity that can be tolerated for specific cases. Except for

those inherent limitations that depend upon the laws of physics,

improvements in antenna technology should raise the threshold of

limitations over the next several years.

External antenna-related factors that limit the performance of

satellite antennas include the regulatory constraints upon

frequency bandwidths. the nonuniform distribution of traffic

over the terrestrial coverage region, and cross-polarization

isolation degradation due to rain and other atmospheric

effects. In terms of aperture size, the antenna is squeezed in

opposite directions by external forces. Factors that tend to

increase antenna size include satellite transmit power

limitations and constraints on ground equipment such as antenna

diameter, receiver noise temperature, and transmit power. The

key factors constraining the maximum size of spacecraft antennas

have been the limited available space within the launch vehicle

and the unwillingness of satellite designers to use what has

been perceived to be an immature unfurlable antenna technology.

The performance of space antennas is also limited by

beam-pointing errors due to spacecraft instabilities and

alignment uncertainties caused by structural/thermal support

structure movements and tolerances. These pointing

uncertainties cause the defined coverage areas to be enlarged,

thereby lowering the achievable gain over the coverage region.

7-4
Ford Aerospace &

Communications Corporation

Future satellite antenna systems will also be required to

limit interference outside of the desired coverage region in a

manner similar to the recommendations of the WARC-77 for the 12

GHz band. The interference limitation will demand low

sidelobes, low cross-polarization levels. and sharp beam

rolloffs, not only in the coverage area of interest but

everywhere on the earth. This problem has been exacerbated by

the 1983 FCC ruling that fixed-service communications satellites

o

in geosynchronous orbit may be spaced every 2 along the

orbital arc instead of the previous 4 . These requirements

will tend toward less efficient antennas and will thus require

larger apertures.

7.2.3 Communication Satellite Antenna Technology in 1998.

The state of antenna technology in 1998. is predicted to

evolve through three general categories of development:r -

o Further refinements in existing technology

o Maturation of current experimental work

o New antenna concepts

The first category will result from many modest improvements

in antennas and their associated components, as well as from the

development of more powerful analytical techniques. The net

result from these improvements will be such features as higher

antenna gain, better interference characteristics, increased

frequency reuse, more flexible in-orbit reconfigurability, and

higher levels of reliability.

The second category includes those technologies that are of

great interest today, but for the most part are still in the

experimental stage with regard to space applications. Those

will include the marriage of antennas, microprocessors, active

components, monolithic microwave integrated circuits (MMICs).

and IF beam forming.

7-5
Ford Aerospace &

Communications Corporation

The third category of antenna technology development is more

difficult to predict since it includes ideas that either have

not yet been conceived or have not been advanced in the

literature.

7.2.3.1 Further Refinements in Existing Technology

In order to predict future improvements in communication

satellite technology, it is useful to describe the basic classes

of antennas that are currently in service. The major types of

antennas, more or less in their order of ascending complexity,

are briefly discussed in the following paragraphs.

a. Global Coverage Antennas. Global coverage antennas

provide radiation over the entire surface of the earth

visible from synchronous orbit with as much gain as

possible. A slight amount of beam shaping is often used

to maximize the edge-of-coverage (EOC) gain, and

orthogonal polarizations can be used for two-times

frequency reuse.

b. Spot Beam Antennas. Spot beam antennas provide circular

or elliptical coverage beams over limited regions on the

earth and are sometimes gimballed to make possible limited

mechanical scanning. High-efficiency feeds are usually

used to maximize gain and sidelobe performance. Frequency

reuse is made possible through the use of orthogonal

polarizations. Often the same antenna is used for both

transmit and receive functions.

c. Shaped Beam Antennas. Shaped beam antennas are designed

to concentrate as much energy as possible over carefully

specified coverage areas and as little as possible

everywhere else. Coverage areas can be as small as

certain regions within a single country or as large as the

7-6
Ford Aerospace &

Communications Corporation

area encompassed by the major population centers within an

entire hemisphere. A single shaped beam antenna may

produce one or several independent shaped beams for each

orthogonal polarization, all being connected to different

transponders. The more advanced shaped beam antennas are

reconfigurable in orbit in order to select the correct set

of coverages for each of several possible satellite

orbital positions. It also may be desirable to change

coverage patterns to adjust to variations in

communications traffic.

Key to the success of multiple shaped-beam coverage for

a particular beam is the achievement of very low levels of

cross-polarized energy and sidelobes outside of the

specified coverage region in order to avoid deleterious

interference with and from other beams.

The most common antenna that is used for shaped-beam

antennas is a large (6 to 10 ft) offset reflector fed by

arrays of feed horns. Beam shaping is achieved by

beam-forming networks (BFNs) that provide the appropriate

phase and amplitude coefficients to the feed array

elements. In the case of circularly polarized antennas, a

single reflector is used for both RHCP and LHCP and

separate BFNs form the proper coefficients for each

polarization. Separate antennas are used for transmit and

receive, and high-quality polarizers provide low axial

ratios to ensure low levels of cross-polarization.

Linearly polarized shaped beam antennas are in common

use in the 14/11 GHz frequency bands. Separate antenna

systems are used for the two polarizations, horizontal and

vertical, and grids of parallel wires are embedded on the

surfaces of the reflectors to act as polarization

purifiers. Because of limited room on the spacecraft, the

7-7
Ford Aerospace &

Communications Corporation

horizontal and vertical gridded reflectors often overlap.

Transmit and receive coverage is provided by the same

reflector.

Multibeam antennas that are reconfigurable currently

employ two methods to change beam shapes. The first uses

a stack of fixed power dividing networks and multiple

switches to select the appropriate combinations for

different orbital positions. The second method employs

variable power dividers (VPDs) and variable phase shifters

(VPSs) to reconfigure the beams upon ground command.

d. Multiple Scanning Beam Antennas. Multiple scanning beam

antennas produce many narrow spot beams that can be

electronically scanned anywhere over the coverage region.

The dwell time of a spot beam at each location is made

proportional to the demand for service from that

location. . The antenna includes a switching matrix that

provides rapid interconnections between any satellite beam

and any transponder.

Refinements in existing technology for the types of antennas

previously described that will result in improved technology for

1998 are discussed in the following paragraphs.

(1) Larger Antenna Reflectors. The development of large

antenna technology will be the key to the accommodation of

increased communications satellite traffic by the year 1998.

Current antenna systems are often limited in size and are

relatively complex due to present, launch vehicle packaging

constraints. The size restriction and complexity have resulted

in fundamental performance and reliability limitations of

satellite antennas. By 1998. antenna farms utilizing deployed,

unfurled, and space-erected antennas will be possible. This

development will dramatically alter antenna designs and will

7-8
Ford Aerospace &

Communications Corporation

enable favorable tradeoffs to be made between antenna size and

complexity. The result will be simpler antennas with improved

electrical characteristics and reliability.

Antennas that are deployed are likely to see continued use,

especially at the higher frequency ranges where modest aperture

sizes are adequate. What is meant by deployed antennas are

those that are of solid construction but are stowed for launch

and have main reflectors, subreflectors, and/or feed systems

that are repositioned in-orbit by hinging or some other

mechanical mechanism. These antennas will be of the same

composite materials construction that is currently in use.

However, fabrication techniques must be improved in order to

produce a reflector surface roughness suitable for 30 dB

sidelobes, high gain, and low cross-polarization levels in the

frequency range above 30 GHz. The antenna alignments achieved

after deployment must also receive attention so that antenna

beams with widths of a few tenths of a degree can be accurately

pointed at their targets.

To date, the largest solid reflector that has been placed in

space has a diameter of 12 feet. Reflectors that must

significantly exceed that size will be unfurlable.

Communications antennas operating in the standard frequency

bands might require reflector diameters in the range of 15 to 30

ft.

However, large multiple-beam antenna missions envisioned for

the 1990s have diameters up to 4600 ft for applications in the

15 MHz to 2000 MHz frequency range.

For example. a proposed system that will require large

satellite antennas is the Land Mobile Satellite System (LMSS).

This will be a direct user-to-user system where users constantly

move about. Therefore the user antenna must be small and

inexpensive, forcing the satellite antenna to be large and

7-9
Ford Aerospace &

Communications Corporation

complex. One scenario for this system uses a 180 ft

frequency-reuse multiple-beam satellite antenna operating in the

UHF band.

Several types of large unfurlable antenna concepts are in

various stages of development. These include wrap-rib,

hoop/column, geotruss. box truss, inflatable. and

electrostatically figured membrane designs. These antennas

employ surfaces that are mesh, membrane, solid, and segments.

They could be packaged for launch and then be unfurled or

assembled in space. It will be possible to design these

antennas for zero gravity and thereby significantly reduce

weight. By 1998. it is likely that only a few of the concepts

under study will emerge as those offering the best solutions to

the problem of designing large space antennas.

The largest unfurled reflector that has been used in space is

a wrapped rib design with a diameter of 30 ft. Experience has

shown that achieving the high-precision surface accuracies that

are needed for high antenna performance is very difficult, and

considerable development work remains to be done. Most of the

demonstrated techniques for deploying large reflectors have a

discrete number of control points for shaping the surface, which

causes distortions from true parabolical shape and thereby

degrades gain, sidelobes, and cross-polarization levels. It is

probably safe to predict that by 1998, the more serious problems

will have been overcome, making large, high-performance antenna

systems a reality for frequency bands below Ku-band..

(2) Improved Components. Better performance will be

available from satellite antennas as a result of improved

components, including beam-forming networks, feed elements,

polarizers, diplexers. and gridded reflectors.

7-10
Ford Aerospace &

Communications Corporation

o Fixed Beam-Forming Networks. Improvements will be made in

beam-forming networks that will make possible better beam

shaping with less RF loss, less weight, smaller size, and

greater reliability. Low-loss printed circuit techniques

will probably continue to be favored.

o Variable Beam-Forming Networks. The key to variable

beam-forming networks is the use of ferrite variable power

dividers (VPDs) .and variable phase shifters (VPSs), as

well as low-loss switches. These components will be

improved to provide lower loss, smaller size, less weight,

lower temperature sensitivities, more accurate control of

amplitude and phase characteristics, and less power

consumption over larger bandwidths.

o Feed Elements. Feed element improvements will probably

focus on the further development of broadband multimode

horns and microstrip patch radiators.

o Polarizers. Polarizer improvements will be needed to

produce low axial ratios over broad bandwidths, and new

concepts will be developed for the very high and very low

frequency bands.

o Diplexers. Diplexers must be developed for new frequency

bands with the emphasis on high rejection and low loss.

o Gridded Reflectors. More dimensionally stable gridded

reflectors are needed in order to achieve high levels of

isolation for linearly polarized frequency-reuse antennas.

(3) Reflector Antenna Systems. Improvement in reflector

antenna systems will provide better flexibility and higher

capacities for communications satellite systems. These

improvements will result from refined components and more

accurate analytical tools. Broadband multiple beam antennas

7-11
Ford Aerospace &

Communications Corporation

operating with up to 1 GHz of bandwidth will be available. The

off-axis performance of dual-reflector antennas will be

considerably improved by specially shaping both reflectors to

minimize phase errors. The feasibility of this technique has

been demonstrated on a NASA-sponsored contract with Ford

Aerospace, but much work remains to convert the experimental

antenna design into one that is flight worthy.

Reconf igurable beam antennas with coverage contours that are

adjustable in-orbit will have higher gains and improved

inter-beam isolation due to better components and superior

design techniques. It will be possible to reconfigure beam

coverages in orbit to provide communications under a variety of

coverage scenarios.

Improvements will be made in electronic beam scanning

capabilities in order to meet the requirements for global

coverage with high EIRP beams for low-cost, small-diameterantenna ground terminals. Multiple, rapidly scanned, narrow

beams will be provided for widely scattered users.

Antenna systems will also need to handle higher power levels

for DBS and for other, communications systems that include small

user antennas.

(4) RF Sensing and Pointing. RF sensing and pointing will

become increasingly important as the antenna beamwidths get

narrower and antenna performance becomes more critical.

Attitude errors in the platform and thermal distortions in

structures can cause significant antenna pointing errors.

particularly for users near the edges of beam coverage. The

current spacecraft pointing accuracies are about ±0.1 .

Narrow beams, with beamwidths around 0.1 . will come into use

by 1998. particularly for satellite-switched time-division

multiple access (SS-TDMA) systems.

7-12
Ford Aerospace &

Communications Corporation

Thus it is important for all types of communications antennas

to point their beams with great accuracy. One method by which

this can be achieved is to use each antenna as a sensor to steer

its own radiation pattern and continuously correct any pointing

errors. By this means, it will be possible to use the antennas

themselves in either a monopulse or step-track mode of operation

to actively track one or more ground-based beacons.

There are, however, problems to be overcome in order to employ

this technique. First, the antenna configuration must be such

that the sensing signal that is obtained through the receiving

mode will track with the transmitted beam, which may use a

different antenna. A second problem is that of implementing RF

sensing in shaped-beam antennas. Possible autotrack

implementation schemes might include separately gimballing each

antenna. movable feed systems. movable reflectors. and

electronic scanning.

(5) Array Antenna Improvements. Array antennas will also

undergo significant advancements over the next 15 years. In

some applications, there may be performance benefits to be

gained by using a phased array directly rather than as a feed

system. In principle, phased arrays can precisely produce the

desired phase and amplitude excitation of each element to

achieve any physically realizable tradeoff between gain and

sidelobe levels and can also produce rapid. inertialess

scanning. Arrays can form fixed, low-sidelobe beams or multiple

beams, and their theory is well developed.

A problem that has limited the use of large phased arrays is

that enormous numbers of feeds and dissipative components are

needed. To produce adequate performance without the use of

large numbers of array elements, research has been performed

with arrays that comprise a relatively small number of large

radiating elements.

7-13
Ford Aerospace &

Communications Corporation

Another attractive array development is the development of

printed circuit antennas, whereby the entire antenna system is

implemented with a few layers of circuit boards and stripline or

microstrip radiating elements. Stripline elements can be

developed with bandwidths up to an octave, but microstrip

elements are relatively narrow band. Printed-circuit techniques

are attractive for low frequency arrays, where conventional

array elements would be large, and at high frequencies, where

hundreds or even thousands of elements could be needed.

(6) Lens Antenna Improvements. Lens antennas have been

studied for several decades, but. with the exception of the

waveguide type, the technology for satellite communications

antennas is immature. Lenses are attractive, however, because

of their exemplary scan characteristics, which can produce

well-shaped beams at large scan angles. The major limitations

of lenses have been their complexity and weight. As frequencies

of application become higher and space-erectable antennas become

possible, lenses are more likely to find their way into space.

Although solid dielectric lenses are heavy for conventional

communications frequency bands, interest in higher frequencies

has made them attractive candidates for use in high performance

antennas. For frequency bands above Ku-band. the weight penalty

associated with dielectric lens antennas is relatively small.

They are also inexpensive and reliable, and recent advances in

the development of low-loss materials make their future use

certain.

(7) Multifeed Antennas. Single antennas operating at

several frequency bands have been employed by using such

techniques as frequency selective surfaces (FSSs) and

multifrequency feeds. For example. the ATS F&G antenna

reflector operated at VHF, UHF. L-band. S-band. and C-band

frequencies. The CS antenna produced shaped beams from a single

reflector at both the 6/4 GHz and 30/20 GHz bands.

7-14
Ford Aerospace &

Communications Corporation

Multifeed antennas are expected to be used in the future

because of the benefits of raultifrequency coverage from a single

aperture. A concept that appears to have merit for future

applications is a dual-reflector system with four subreflectors,

one for each operating frequency band. The subreflectors

overlap, each being made up of frequency sensitive elements,

except for the one in the back, which is solid. Each of the

three front subreflectors is reflecting at its own frequency and

is transparent to the other three frequencies. The

subreflectors are positioned so as to allow for feed separation

in the focal region for the four feeds. This scheme requires

sufficient separation between the bands for the FSS to operate

properly, such as combined use of L, C. X, and K bands.

(8) Mechanical and Materials Improvements. Improvements in

antenna mechanical and materials design will be required for the

stable construction of large antenna systems. The effects of

different antenna locations, active and passive thermal control

systems. and basic materials technology must be further

developed for 1998 antenna systems.

(9) Reduction in RF Interference. A large structure that

includes many antennas of various types and sizes and operates

over a large range of frequencies could cause deleterious RF

interference and scattering that would reduce the achievable

isolation between beams. These effects need to be evaluated

analytically during the antenna design phase in order to achieve

the required 30-40 dB isolation in orbit. The analytical

consideration of proximity interference must be part of the

mechanical and structural design of the antenna farm

configuration.

(10) Improved Analysis Programs. The sophistication of

today's satellite antenna technology was made possible by the

development of excellent computer analysis programs. These

programs and the models they employ must be vastly improved so

7-15
Ford Aerospace &

Communications Corporation

that future antenna systems, which will be too large to test and

develop on the ground, can be assembled in space with full

confidence that they will perform as predicted. The complex

radiation patterns, low sidelobes, and low cross-polarization

levels needed must be achievable in the antenna farm environment.

(11) space Measurement Techniques. Testing and

characterizing large antennas in space will require the

development of new measurement techniques.

7.2.3.2 Maturation of Current Experimental Work

The second category of communications antenna advancements

will come from technology that is currently in the experimental

stage but will be mature by 1998. The areas of special interest

include antennas combined with solid-state devices and MMICs to

form active antennas and the incorporation of microprocessors to

form adaptive antennas. Antennas with electronically

controllable radiation characteristics will produce steerable

beams, multiple beams, shaped beams, and adaptive radiation

characteristics.

(1) Active Transmitting Antennas. A method of obtaining high

downlink effective radiated power that appears attractive

for future applications is to incorporate solid-state

microwave power sources at each antenna array element.

The arrays can be used as either large aperture direct

radiators or as feeds for reflectors or lenses. These

active transmitting antennas will produce higher output

power levels than can be generated by the single devices

now in use and will also eliminate the effects of

associated power-dividing networks.

7-16
Ford Aerospace &

Communications Corporation

The active array combines miniature GaAs PET or

beryllium low-power amplifiers that are preceded by diode

phase shifters on MMIC substrates using batch process

techniques. These solid-state amplifiers and phase

shifters are assembled as individual modules with one pair

per feed element. The modules provide variable phase and

variable power amplification for each of two orthogonally

polarized beams. The variable phase shifters are digital

and can have 5 or more bits of resolution 'for dynamic

phase control. The variable power amplification function

is used for dynamic amplitude control.

The use of MMIC modules will allow for fast beam

switching (10-100 nanoseconds) for TDMA systems and will

make phased arrays practical for communication satellite

applications. They also provide the benefit of

significant reductions in weight, size, and costs. One of

the key challenges will be to produce large numbers of

amplifiers with closely matched and stable amplitude and

phase characteristics.

Another application of amplifiers will be to combine

them with conventional beam-forming networks.

Reconfigurable beam-forming networks that contain several

layers of variable power dividers or a switching matrix

suffer from high RF losses. This loss can be overcome by

including a power amplifier at the terminals of each BFN

port.

(2) Active Receive Antennas. A multiple-beam receive antenna

could include low-noise amplifiers at the terminal of each

array feed element to overcome the effect of BFN and

switch matrix loss.

7-17
Ford Aerospace &

Communications Corporation

Another approach is under development for multiple

scanning beams, where rapid connections must be made

between any satellite transponder and any antenna beam.

The conventional approach to this problem is to employ a

complex RF switching tree, which can have significant

insertion loss before the noise figure has been

established in the receiver front ends. Also, many of

these switching structures impose constraints on the

possible combinations of beams that can be simultaneously

selected. The alternate approach is to connect a separate

receiver front end to each feed where the signal is mixed

to an intermediate frequency (IF). Beam selection is made

after the noise figure has been established. All of the

various methods of scanning are then possible, including

beam switching, and can be carried out at IF where

amplification is readily available and lumped constant

circuits may be used.

In addition, the flexibility of the IF switch matrix

places no limits on the combinations of beams that may be

simultaneously selected and also permits the addition of

beams if phase coherence is maintained in the receiver.

This will allow for beam positions intermediate to the

discrete contiguous beams. Equivalent techniques of

mixing are possible for transmit antenna applications.

(3) Adaptive Antennas. Adaptive antennas use microprocessors

to control the radiation characteristics of the antenna

and to produce some predetermined coverage performance

during changing conditions. Although adaptive antennas

are usually thought of in their military application of

nulling out interfering signals, they are certain to see

widespread use over the next 15 years in the field of

satellite communications. The primary application will be

to maximize signal strength and minimize interference.

Antenna patterns can be adaptively modified to accomplish

the following.

7-18
Ford Aerospace &

Communications Corporation

o Change coverage patterns to accommodate variations in

communications traffic,

o Change feed coefficients between adjacent multiple beams

to reduce interference between them that varies with

time,

o Change EIRP footprints to reduce the effects of rain

fading and other atmospheric degradations,

o Compensate for spacecraft instabilities by slightly

varying pattern shapes,

o Produce pattern minimums toward terrestrial interfering

sources,

o Compensate for thermally or dynamically introduced

antenna shape changes.

As an example of adaptive antenna control, consider the

problem of providing adequate coverage during localized

rain fading. Currently for shaped-beam coverage at higher

frequencies. a significant. power margin must be

incorporated in communication satellites to prevent

excessive outages due to rain fades. This margin could be

reduced if the coverage beams were adaptively controlled

to temporarily provide higher antenna gains to the small

regions that are suffering from rain attenuation. This

power would come from the larger portion of the coverage

region where conditions are clear. Relative signal

strengths to each ground station would be monitored and

the information transmitted to the onboard microprocessor

that would appropriately adjust the phase and amplitude

coefficients of the antenna via a reconfigurable BFN to

reshape the gain contours.

(4) Intersatellite Links. By 1998, it is likely that there

will be a number of space platforms, each with its own

antenna farm. To add to the total communications network

flexibility, these platforms will be interconnected in

space by intersatellite links. The interconnections will

7-19
Ford Aerospace &

Communications Corporation

be through tracking antennas that will probably operate at

frequencies not suitable for ground-to-space

communications because of high atmospheric attenuation,

such as 60 GHz or optical laser links.

7.2.3.3 New Antenna Concepts

The antenna technology of 1998 is not possible to foresee

because most of the ideas have not yet been conceived or, if

they have been, are not widespread knowledge. One idea that has

been advanced in the literature is the use of CO laser

communication systems that would link satellites in synchronous

orbit to each other and to low-orbiting satellites. Another

idea that may produce results is the combination of antennas and

fiber optics within the space platforms. Also, it is likely

that many new combinations of active devices and microprocessors

will enable antennas to become more and more closely associated

with the signal processing portions of the satellite.

7.2.4 Summary of Antenna Technology

The critical technical and cost saving technologies for future

space communication platform antenna system are expected to

include:

o MMIC Technology. Large phased arrays capable of rapid

scanning will require MMIC technology to be cost effective

and technically feasible.

o Wide Angle Scanning. Electronic scanning is required for

TDMA scanning beam systems. However, the problem is to be

able to use one antenna to scan a large area. in the limit,

earth scanning of ± 10° from GEO is required. For a

scanning beam size of 0.3 this is +. 30 beamwidths. Ford

Aerospace has achieved +_ 14 beamwidths scanning with less

7-20
Ford Aerospace &

Communications Corporation

than 1 dB scan loss in the 20 GHz POC Antenna for

NASA/LeRC. However, requirements for increased scanning

will require a novel approach to the problem.

o High-Speed Processor Technology. Control of possibly tens

of thousands of elements in microseconds will require great

advances in computation speed and memory access time.

The integration of a 1990's technology spacecraft antenna with

other payload equipment items is shown in Figure 7.2-1. Much of

the electronics may be combined within a relatively few physical

packages.

The risks associated with various antenna applications is

given in Table 7.2-1.

Table 7.2-1

Risk Associated With Various Antenna Applications

Application

C-Band

Ku-Band

'Ka-Band. FSS

Ka-Band. GPS

Maritime

Mobile

ISL

DBS

Considerations

Solid Reflector. BFN

Solid Reflector. BFN

Active Switching. BFN

Scanning, MBA

Helical

Large Reflector. Many Beams

Pointing. Acquisition

Reflector. BFN

Risks

Low

Low

Moderate

Moderate-High

Low

Moderate

Moderate

Low

7-21
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7-22
Ford Aerospace &

Communications Corporation

An estimate of the current and future limitations on

spacecraft antenna reflector size is shown in Table 7.2-2.

Table 7.2-2

Spacecraft Reflector Size Limitations (ft.)

Application Current 1985 1993

C-Band Solid 15 - -

Flex 30 40 75

Ku-Band Solid 15 - -

Flex 15 20 30

Ka-Band Solid 15 - -

Flex - - 20

UHF • Solid 15 - -

Flex 100 200 300

Note: Solid Reflector Limited by Shuttle.

- C-Band appx. 1.25° (15 ft STS diameter)

- Ku-Band appx. 0.45° (15 ft STS diameter)

- Ka-Band appx. 0.30° (Overall Pointing Constraint)

7.3 RF TRANSPONDER TECHNOLOGY

7.3.1 Background

The technology base for transponder implementation in the

year 2000 must be directed to high performance and long term

reliability. A relatively small quantity of the spacecraft

units is required and hence cost may be assigned a lower

priority in elevation assessment.

7-23
Ford Aerospace &

Communications Corporation

The key technology developments to support space platform

communications are projected as follows:

o Improved TWT efficiency and extended life

o Development of higher power SSPA's at Ku- and Ka-bands

o Development of dielectric resonator materials for use

in filters and oscillators

o Continued application of GaAs MM1C technology

o Improvement in receiver noise figure

o Development of optical interconnects between components

7.3.2 Power Amplifier

TWTA Technology The projected power output from TWT

amplifiers for various frequency bands is given in Table 7.3-1.

It should be noted that current amplifiers in the C and Ku-bands

are already high enough power output given the ground flux

density limitations for CONUS coverage. The TWTA efficiency is.

expected to increase with time as shown in Figure 7.3-1. It is

predicted that the efficiency of Ka-band TWTA's will reach 50%

by the year 2000.

Table 7.3-1

»•

TWTA Output Power For Selected Frequency Bands

Frequency (GHz) Present - 1985 1985 - 1990 1990 - 1995

2 (Maritime) 150 W 300 W 400 - 600 W

12 (DBS) 200 W 260 W 300 - 500 W

20 4*. 5/50 W 100 W 200 - 400 W

30 3*. 20 W 100 W 150 - 250 W

60 5**. 10 W 20 W 80 - 200 W

* Slow-wave Helix

** Coupled Cavity

7-24
Ford Aerospace &

Communications Corporation

100

o

5 50

u.

it.

U."

C-BAND

KSJ-BAND

Ka-band

I

1970 1975 1980 1985

YEAR

1990 1995 2000

Figuire 7.3-1, TWTA Efficiency Predictions

The TWTA on-orbit operating lifetime is of key economic

concern in determining sparing and replenishment strategies. As

shown in Figure 7.3-2. the most probable lifetime is about 10

years in year 2000 using M type dispenser cathodes. A lifetime

of 20 years is projected for field emission cathodes. However,

the associated risk associated with achieving that life is very

high.

Solid State Amplifiers The projection of output power

capability for irapatt diode amplifier technology is shown in

Figure 7.3-3. Power levels of 10 watts per device are expected

at 20 GHz frequency for 1990 implementation. The projected

output power for GaAs FET devices is shown in Figure 7.3-4. In

the 10 to 20 GHz frequency range the output power per device is

expected to roughly double in the eight years from 1985 to 1993.

7-25
Ford Aerospace &

Communications Corporation

30r20-

10-

2A/cm

CATHODE

LOADING

_

FIELD EMISSION CATHODE -v -x"

CONTROLLED N!

POROSITY CATHODE^ j

M TYPE DISPENSER-^ _\-4—

CATHODE ~j

TYPE B CATHODE-^

i i i i

HIGHLY

.^SPECULATIVE

^

-•-•? . , - _ _-

- " •/' SPECULATIVE

_— — — ^~ .'

PROBABLE

i i

1970 1975 1980 1985 1990 1995 2000

YEAR

Figure 7.3-2 TWTA Life Projections

IMP 11 i

COMMERCIALLY

AVAILABLE

DEVICES

o UBORATORY

RESULTS

\i * i t I 1 t t it I J I tit

10 100

FREQUENCY (GHz)

Figure 7.3-3 Projection For IMPATT Diode Devices

7-26
Ford Aerospace &

Communications Corporation

100 p

10

0.1

l l

LABORATORY

RESULTS

\PROJECT10N

COMMERCIALLY Vx

AVAILABLE

DEVICES

1993)

GOALS OF CURRENT

SPONSORED

RESEARCH

1 i i i ijii i

1 .10 100

FREQUENCY (GHz)

Figure 7.3-4 Projection For GaAs FET Devices

7.3.3 Power Combining Techniques

The available techniques for combining power of separate

amplifier devices is shown in Figure 7.3-5. In addition, nonresonant combining techniques are expanding and provide a number

of advantages. The relative advantages and disadvantages of the

power combining techniques are summarized in Table 7.3-2. All

of the techniques have been used in various applications

depending on the primary requirement. All of the techniques

require relatively good control of absolute phase shift as well

as phase variation with temperature. The temperature between

devices must be controlled also in order to" control phase.

7-27
Ford Aerospace &

Communications Corporation

GaAs FETs IMPACTS

CHIP COMBINING

RESONANT

CAVITY

BINARY

COMBINERS

5

JL

N-WAY

COMBINERS

SPATIAL

COMBINING

HIGH

POWER AMPURER

Figure 7.3-5 Power Combining Techniques

Table 7.3-2

Relative Merits Of Power Combining Techniques

TYPE

NGN-RESONANT

BINARY COMBINER

N-WAY COMBINER

SPATIAL COMBINING

RESONANT

ADVANTAGES

BROAD BANDWIDTH

AMPLIFIERS ISOLATED

GRACEFUL DEGRADATION

EASE 0; IMPLEMENTATION

LOWER INSERTION LOSS

SMALLER SIZE AND WEIGHT

USEFUL FOR ANY VALUE OF N

LOWEST INSERTION LOSS

EASE OF IMPLEMENTATION

HIGHEST EFFICIENCY

SMALLEST SIZE AND WEIGHT

DISADVANTAGES

HIGHEST INSERTION LOSS

LARGEST SIZE AND WEIGHT

LIMITED TO < 16 DEVICES

DIFFICULT TO IMPLEMENT

REQUIRES DEVELOPMENT

LESS ISOLATION

REQUIRES COMPATIBLE

ANTENNA DESIGN

CATASTROPHIC FAILURE

NARROW BANDWIDTH

LIMITED TO < 10 DEVICES

7-28
Aerospace &

Communications Corporation

7.3.4 Receiver Technology

The current state-of-the-art noise figures for various

receiver devices is shown Figure 7.3-6. GaAs FET and parametric

amplifier implementations are expected to yield the lowest noise

figure at all frequency bands as presented in the figure. While

some improvement will be achieved over equipment available

today, no significant improvement in noise figure is likely to

emerge in the time frame of interest.

CO

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Figure 7.3-6 Noise Figure For Receiver Devices

The overall mixer noise figure performance for various

implementation techniques is shown in Table 7.3-3. The use of

GaAs image enhanced mixers is expected to yield a noise figure

of 6db for 20 GHz operation.

7-29
Ford Aerospace &

Communications Corporation

Table 7.3-3

Comparative Mixer Noise Figures

FREQ.

(GHz)

10-18

18-26

26 - 40

REL COST

BALANCED

Si

7.0

7.5

8.5

1.0

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6.5

7.0

7.5

1.2

DBM

Si

7.0

7.5

8.5

1.1

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6.5

7.0

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IR

Si

7.5

8.0

9.0

3.0

M

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7.0

7.5

8.0

3.2

IM. ENH.

Si

6.0

7.0

8.0

5.0

GaAs

5.5

6.0

6.5

5.2

NOTE: (SSB NFJI. = 1.5 dB)

The projected future performance, physical characteristics

and costs of an advanced microwave receiver implementation are

presented in Table 7.3-4. It can be seen that while there are

sizeable reductions in size, weight, and cost, the improvement

in noise figure performance is not that dramatic. In general,

the trend will be to lighter, lower cost hardware but not

significant improvement in performance.

Table 7.3-4

Advanced Receiver Characteristics

Parameter

Noise Figure (dB)

Bandwidth (GHz)

Size (Inches)

Weight (Grams)

Cost/Amplifier

Microwave 1C

3.1

0.5

0.43x2.25x0.5

17.7

$4.600

Advanced

Microwave 1C

1.9

2.0

0.2x0.8x0.17

8.0

$3,400

Monolithic

Microwave 1C

1.9

2.5

0.1X0.2X0.1

3.0

$920

7-30
Ford Aerospace &

Communications Corporation

7.4 ON-BOARD PROCESSING TECHNOLOGY

The use of advanced on-board processing technology can

significantly enhance the performance of the total

communications system. - Several areas of expected benefits

include:

o Increased Connectivity - This can be achieved by changing

the transmission path dynamically by SS TDMA switching or

demodulation/remodulation schemes.

o Increased Capacity - This is accomplished by improving

satellite fill factors,

o Increased Communications Link Efficiency - This can be

accomplished by separating the uplink and downlink using

regeneration,

o Increased Flexibility - Permits potential ability to

combine FDMA/FM and TDMA uplink traffic on the spacecraft

as part of the same network.

A summary of the application of various processing

technologies by payload transponder element is shown in Table

7.4-1.

•

The configuration of an advanced satellite transponder

incorporating a base-band processor is shown in Figure 7.4-1.

It is anticipated that the processor developments associated

with the ACTS program will be applicable to space platform

applications.

An example of A/D conversion processing as used in Scenario

VI-A configuration for spot beam frequency reuse at C-band is

shown in Figure 7.4-2. This technique provides flexible

interconnectivity. impro.ves fill factors, and is transparent to

user operations.

7-31
Ford Aerospace &

Communications Corporation

Table 7.4-1

Application of On-Board Processing Technology

Technology

^s.

— ^^

Punc t i on*"^^^

SS-TDMA

IP PROCESSING

MOD/DEMOD

A/D, D/A

RPCOMPONENTS

ENCODE/DECODE

MUX/DEMUX

SWITCHING

CONTROL

DATA DIST'N

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Baseband prcessing technology is currently moving at a rapid

pace. The efforts of NASA LeRC and Motorola. Inc. in the

technology contracts to develop the processor for the NASA ACTS

program have made great strides in the device area, as well as

high speed burst modulators and demodulators. The basic concept

of on-board demodulation, baseband digital switching. and

remodulation has been demonstrated by the proof-of-concept model

built by Motorola for NASA LeRC and documented in (Ref. 45).

As part of the program. Motorola developed burst demodulators

at 27.5. 110. 220 and 550 Mbps. It also demonstrated an

architecture that could be expanded to handle digital switching

of up to 10 Gbps of capacity, which is all that is required for

the scenarios developed in this study.

7-32
Ford Aerospace &

Communications Corporation

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While further improvement in high data rates, reductions in

mass and power, and improvement in space radiation hardening are

required for implementation into the platform, the concept

designs have been proven by the ACTS work.

Table 7.4-2 provides the performance characteristics of the

current state-of-the-art in microwave switches. The data is

based on the Ford Aerospace work performed for NASA LeRC (Ref.

41) on the technology development contract for the NASA ACTS

program. Current work is on-going in the development of a

monolithic switch module for a 10x10 chip, and should be

available in the time frame of interest in this study.

7.5 PAYLOAD ON-ORBIT SERVICING TECHNOLOGY

A geostationary platform represents a significant investment

in a single element of a communications system. Therefore, high

reliability of the system is desirable in order'to achieve the

desired payload lifetime. One method of achieving high

reliability is to design the payload to allow for in-orbit

servicing and/or repair.

A modular design of the payload facilitates in-orbit

servicing. However, designing for modularity impacts both the

cost and weight of the payload.

Three elements must be considered in assessing the economic

viability of in-orbit servicing of the payload: (1) modular

design impacts on the payload. (2) design impacts on the

platform bus. and (3) costs of .the servicing module (including

operations and transportations costs). The major emphasis of

this study was the design impacts on the payload. Several of

the potential payload servicing concepts are shown in Table

7.5-1.

7-35
Ford Aerospace &

Communications Corporation

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A review of on-orbit servicing resulted in the following

forecast for payload servicing technology:

o GEO payload servicing considered unlikely due to service

outages.

o No "Shirt Sleeve" LEO facility provided

o Only EVA and remote manipulator capability

o LEO operations for deployment, check-out, and repair or

return to Earth

o No payload assembly at LEO

From the limited review during the study. LEO servicing for

platform fueling and mating of space based transfer stages

appear to be the most beneficial aspects of on-orbit servicing

envisioned in the mid to late 1990's time frame. The

possibility of LEO repair of failed components, prior to transfer

to GEO may also have future benefits. However, the economics

are difficult to assess at this point given the large

uncertainty in both the capability and the cost associated with

these functions.

7.6 GROUND TERMINAL TECHNOLOGY

This section addresses the technology development areas that

should be pursued in order to achieve high performance, low-cost

terminal implementation which would operate in concert with

future space platform systems.

Among the key technology drivers would be the following:

o Advanced modulation techniques for high bandwidth

efficiency, ie, greater than 2 bits per hertz.

o High speed modems incorporating MMIC and LSI

implementation.

7-38
Ford Aerospace &

Communications Corporation

o Combining techniques to achieve 6000 voice circuits per

channel,

o Combining techniques to permit multiple video circuits

per channel.

Other developments for the antenna. RF subsystem, digital

equipment and user interface equipment are detailed subsequently.

7.6.1 Terminal Antenna Development

The technology development of the Ku-band and Ka-band antenna

subsystem centers on providing "low cost" equipment within the

constraints of the EIRP and G/T performance requirements.

Low Cost Reflector Panel Recommended areas for technology

development include investigation of alternate manufacturing

methods. Techniques to be examined should include closed die

molding of fiber reinforced plastic for grid stiffened panels,

die stamping and warm forming of aluminum for single skin

panels, and stretch forming of aluminum for either frame and

skin panels or stamped single skin panels.

The most feasible method should be determined with

consideration of required accuracy. recurring costs,

nonrecurring tooling and development cost, consistent production

accuracy, and scrap rate. A development plan would fabricate

sample panels and test for structural characteristics and

surface accuracy under various environmental conditions.

Feed Horn The technology development should investigate

alternate corrugation designs and horn concepts. Cost-effective

manufacturing techniques to be evaluated would include

investment casting, electroforming, machining, and die casting.

A test program would evaluate performance of promising concepts.

7-39
Ford Aerospace &

Communications Corporation

Orthoroode Junction and Receive Filter A similar plan to that

of the feed horn should be followed for the filters.

Manufacturing techniques would include electroforming.

investment casting, and split block machining.

Dielcone Feed A development plan would investigate the

cost/performance benefits that may be achieved from the use of a

dielcone feed. This includes less RF blockage, no struts, and

weather tight configuration. The design must be broadband with

low loss and low VSWR. Fabrication and electrical/mechanical

testing would be required.

Severe Weather Environment Controls A technology development

effort could be implemented to investigate alternate deicing

methods. Topics to be examined include temperature distribution

and gradients, power requirements, chemical deicing agents and

potential corrosive effects, and durability of various coatings.

7.6.2 RF Subsystem Development

There are no RF equipment items that fall in the "must

invent" category. The basic technical capabilities exist in the

industry partly as a result of continuing intensive development

of millimeter wave missile guidance and ECM technologies. What

is currently lacking is a significant thrust specifically

towards Ka-band commercial communications needs.

For receivers, GaAs FET development is yielding transistors

with noise figures of 2.7 dB at 20 GHz. which is believed

compatible with the goal of a 4 dB overall noise figure for the

receiving system. This latter figure is in the region where

improvements of any significance in overall system noise

performance come at the expense of relatively major enhancements

in the noise characteristics of the low noise solid state

devices themselves. This is largely due to the swamping effect

7-40
Ford Aerospace &

Communications Corporation

of external noise sources at these frequencies; items such as IR

losses, antenna noise and added noise due to rain activity. As

a result, the cost benefit for the further development of

improved low noise devices will be marginal.

Two areas for significant development improvement would be:

a) integration of the low noise front end coupled with the first

downconversion stage to provide a single moderate cost low noise

receiver module, and b) development of local oscillator modules

specifically for the Ka-band requirements.

A continuation of solid state power amplifier development

would be beneficial. A parallel combination of devices should

yield an output power of 20 W or more. The cost efficiency and

reliability comparisons of solid state versus the traveling wave

tube approach are not well established at this time.

7.6.3- Digital Equipment Development

No new technology needs to be developed for implementation of

either the TDMA or the FDMA terminal modem and processor.

However, although extensive use has already been made of large

scale integration (LSI) circuitry implementation previously

developed, additional usage of LSI can further reduce the piece

parts count. This parts list reduction would result in a net

recurring cost savings for a production terminal. In addition,

the reliability of the terminal would be improved due to an

increased MTBF.

Several other areas have been identified to reduce terminal

development and recurring costs. The first area where costs

should be significantly reduced is the integration of the user

interface and DAMA controller functions into the baseband

processor. The application appears to be ideal for another

custom LSI to significantly reduce the size and complexity of

the DAMA controller.

7-41
Ford Aerospace &

Communications Corporation

A second area where costs could be reduced is the increased

use of newly evolving high speed analog LSI. Use of this

technology would further reduce the complexity of the

demodulator and modulator.

A third area for potential cost savings is the terminal

reliability. The reliability of a TDMA terminal is

significantly influenced by the use of parts with different

packaging and screening levels.

The overall software architecture reguires additional

definition. Although this is an overall system problem, much of

the operational software resides in the terminal processor. The

software requirements must be properly addressed before

committing to station hardware; otherwise, increased costs will

be incurred as the software/hardware interactions develop.

7.6.4 User Interface Development

This subsystem of an advanced ground terminal may be most

affected by ongoing technological change.

The International Telecommunications Union. (ITU) through the

International' Telegraph and Telephone Consultative Committee

(CCITT). is currently devoting considerable effort towards the

definition of network standards for the future Integrated

Services Digital Network (ISDN). The activities are being

closely monitored by national PTTs. which are also progressing

in adapting their own networks to ISDN compatible digital

connectivity. They are also developing subscriber interconnect

concepts that will extend this to the user Digital Subscriber

Line (DSL). The "basic" ISDN access is at 64 Kbps and the

"primary rate" access is at 1.544 Mbps.

The low rate terminals should be configured in an ISDN

compatible way. The benefits would be:

7-42
Ford Aerospace &

Communications Corporation

o Standardization of interfaces and protocols

o Alleviation of current conceptual/technical difficulties

in providing dial-up data service

Many low cost key elements of the user interface will become

available as IC/LSI components for ISDN development.

7.7 FREQUENCY REUSE

The capacity of a communications satellite can be increased

by use of spatially isolated or polarization isolated antenna

beams. The required isolation between reused bandwidth is

typically 25 to 30 dB, but may be lower than 10 dB. depending on

the signal characteristics and type of modulation.

There will always be some amount of signal energy transferred

from one polarization to the other during the transmission.

This is called the cross-polarization effect, and results in

some level of interference when there is a second signal

transmitted in the other polarization. It is specified by the

cross-polarization isolation (XPI). Crosspolarization in

transmission or reception can occur for any of the following

reasons:

o Antennas (due to the reflector, the offset feed, phase

errors, etc)

o Polarizers (used for circular polarizations)

o Misalignment of antenna axes (linear polarizations)

o Orthomode transducer

o Precipitation on the antenna

The cross-polarization effects of the propagation medium can

occur from either of the following sources:

7-43
Ford Aerospace &

Communications Corporation

o Raindrops. The rain cross-polarization is due primarily

to the nonsphecical shape of raindrops, which fall as

flattened, oblate spheroids. The cross-polarization due

to clouds and snow is much smaller.

o Faraday rotation. This effect is due to the charged

particles in the ionosphere, and only is a problem for

linearly polarized signals.

In order to achieve optimum communications performance it may

be desirable to develop antennas for ground applications which

would track the desired polarization orientation.

7.8 IDENTIFICATION OF KEY TECHNOLOGY DRIVERS

7.8.1 Overall Technology

Major strides in transponder utilization have been made with

systems that carry an order of magnitude more voice circuits

than just 10 years ago, ie. from 600 half-voice circuits per 36

MHz transponder to 6000 half-voice circuits today (see Table

7.8-1 for current use capacities). While this trend will

flatten out, additional capacity gain will be made in systems

that have higher utilization with better interconnectivity and

distributio'n on-board. Packet switching, better access methods'

and system algorithm software with high capacity computers will

improve the effective throughput of a given transponder

channel. In addition. improvements in antenna sidelobe

performance and "smart" receivers on the ground will allow

closer spacing of satellites should it be required.

The major competitive technology, fiber optic terrestrial

systems, is developing very rapidly and will be a significant

influence in the future communications market. Figure 7.8-1

shows a comparison of investment cost and operating cost

comparison of trades for satellites and fiber optics. It can be

7-44
Ford Aerospace &

Communications Corporation

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7-45
Ford Aerospace &

Communications Corporation

Table 7.8-1

Comparative Capacities of Communication Satellite Transponders

for Various Techniques in Current Use (1)

A.

B.

C.

D.

E.

F.

G.

H.

I.

Source

Coding

Compandi ng

Companding/SSB

64 kbps PCM

64 kbps PCM

32 kbps PCM

32 kbps PCMDelta

Baseband

Multiplexing

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FDM

FDM

FDM

FDM

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TDM

TDM

TDM /OS I

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FM

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FM

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QPSK

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Transponder Access

FD (SCPC)

FDMA (MultiCarriers)

Single Carrier

Single Carrier

(FDMA)

FDMA (MultiCarriers)

TDMA

TDMA

TDMA

Number Equivalent (

Voice Channels

500

600-800

1800

2800

6000-7000 (3

600-800

800

1400

2800

(1)Capacitie s shown are for comparison purposes and based on typical 36 MHz bandwidth

transponders with C-Band earth station antenna diameters of approximately 10m.

(2) Number refers to one-way voice channels.

(3) Somewhat less with more than 2 frequency reuses.

seen that in the 1985-1995 time period the trend shows fiber

optics falling at a faster rate than current day satellites.

This leads to the need for a high capacity, high utilization

satellite system to reduce the per circuit costs of satellite

circuits to be competitive with fiber optics. Figure 7.8-2

shows the equivalent crossover distance for various modulation

and access types versus fiber optics and it can be seen that for

distances in excess of the 500-800 mile range, high capacity

satellite systems are still more cost effective.

7-46
Ford Aerospace &

Communications Corporation

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7-47
Ford Aerospace &

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7.8.2 Component Technology

During the study, care has been taken in the definition of

the payloads to utilize technology and advancement consistent

with a 1994 mature basis. This is consistent with a schedule

that has an operational platform launch in the 1998-2000 time

period. The items identified in the next section. 7.8.2. would

have to be developed prior to 1994. The component designs

should start in approximately 1986-87 to define the detail

device requirements by the 1989-90 time frame, with subsequent

proof-of-concept models to be built and tested in the 1990-94

time frame.

During the payload definition task each of the identified

component areas described the current level technology and the

projected technology and this is included in Section 5 of this

report. In reviewing these inputs, the following majo'r new

component drivers were identified:

a.. Programmable frequency shifters to allow second tier

switching at a packet level in a SS-TDMA architecture.

This allows switching on a TDMA basis and routing without

demodulation and remodulation to a circuit level as is

done in some baseband processors.

b. Baseband processor to service the small user and direct

to user applications. The capacities used in the

previously defined payloads range up to 9.0 Gb/s of

capacity, which is about 3 times the capacity of the

planned ACTS processor.

c_. High speed analog to digital converters to provide

on-board format conversion from FDM/FM to digital to

allow on-board switching and routing at a packet level or

even to the voice ground facilities with new generation

on-board systems.

7-48
Ford Aerospace &

Communications Corporation

d.. Development of a methodology to track polarization

variation at Ka-band yields the capability to re-use the

2.5 GHz of bandwidth in high density traffic areas such

as New York and the Chicago/Detroit area. This re-use is

one of the highest payoff factors for CONUS systems due

to the distributional characteristics of the CONUS

traffic. A study to evaluate its economic and the

concept systems should be started soon.

e_. Dual polarizers for RHCP/LHCP. receive and transmit are

utilized in Scenario VI-B so that only one large 9 meter

reflector is required. Given the large cost of the

unfurlable reflectors, development in their area to allow

use of the single reflector appears economic but should

be evaluated further.

f_. Intersatellite links are an emerging technology in the RF

area with NASA funding the TDAS systems and the military

funding numerous projects. These links look adequate for

the near term capacities of 1.5-2.0 Gb/s. but future

growth to higher capacities will require funding in the

' optical links. Laser ISL's also offer other advantages

for interference immunity and smaller aperature. The

payload in this study assumed RF links given the current

available data. However, if adequate funding in the next

10 years could be provided, laser links could replace the

RF ISL's and would provide a better base for future

growth, increased capabilities and flexibility.

Table 7.8-2 identifies the above listed items, and the

scenarios in which they are used. As mentioned previously, the

use of a polarization tracking scheme for use at Ka-band to

allow the full reuse of the Ka-band frequencies in the high

density trunking areas of New York and the Chicago/Detroit area

is the highest pay-off technology item identified. This

7-49
Ford Aerospace &

Communications Corporation

Table 7.8-2

Critical Technology Use by Scenario

TECHNOLOGY

BASEBAND PROCESSING

- HIGH EFFICIENCY

MOD/DEMOD

- A TO D FORMAT

CONVERSION

ANTENNAS

- POLARIZATION TRACKING

OF Ka-BAND FOR H AND V

REUSE

- DUAL POLARIZER FOR

RECEIVE AND TRANSMIT BANDS

TRANSPONDERS

- HIGH SPEED PROGRAMMABLE

FREQUENCY SOURCE

SCENARIO

II V VI-A VI-B

ISL

- RF OR OPTICAL

X X

X X

X X

X X

X

X X

X X

X X

X X

technique would track the polarization phase disturbed by rain

and other atmospheric disturbances discussed in Section 7.7. It

would then realign the antenna polarization with the received

signal to maintain the necessary cross-polarization isolation

between the orthogonal signals, allowing the two times reuse

based on polarization isolation. This techique is used in all

four communication scenarios in all of the Ka-band payloads.

i

Of the remaining items, the prioritized list of critical

technology items is as follows:

7-50
Ford Aerospace &

Communications Corporation

1) Polarization tracking

2) Programmable frequency source

3) Baseband processing - modulation/demodulation

4) ISL's

5) A to D format conversion

6 Dual polarizers for receive and transmit

The programmable frequency shifter is an alternate to a

significantly expanded baseband processor. The savings in

weight, power, and cost are significant advantages. Since this

item is used in all of the Ka-band payloads. it also has high

payoff in the utilization of the frequency band.

Another high payoff item is the high efficiency modulators

and demodulators. The bit rates used in the scenarios are based

on 960 Mbps. This is almost twice the current ACTS rate, and of

course has a direct ratio effect on the capacity per- orbital

locaation, or requires almost twice the number of transponders,

thus impacting the cost comparisons.

The next most significant item is the ISL's. Without ISL's,

the Scenario VI-A and VI-B platforms are almost meaningless.

The use of ISL's and the ability to eliminate double-hop

transmissions and the associated waste of spectrum, power and

ground equipment make it a high payoff technology item.

The next significant technology item is the high speed A to D

and D to A converters, to allow on-band digital routing while

still accommodating the existing analog ground plant-in-place.

This item adds flexibility to the system, but it is hard to put

an economic value on it without a defined user community to be

addressed or a basis for comparison. Further study of this item

to try and quantify its benefit is required.

7-51
Ford Aerospace &

Communications Corporation

As with the above item. dual polarizers are hard to

evaluate. The cost of two reflectors is well definable as a

should cost for comparison, but the cost of developing the dual

polarizers is not well defined. The overall comparison also

needs to consider the costs associated with launching and

supporting the second reflector from the platform.

7.8.3 Support Technology

There are a number of support technology areas that enhance

all of the above technology studies and also yield reductions in

weight and power for the other major components. A list of the

key items is shown in Table 7.8-3.

Table 7.8-3

Key Technology Support Item

Device Processing (CMOS-SOS, etc.)

Discrete (GaAs) Power amps. Receivers, other

MMIC (RF components)

VLSI (digital components)

Materials Technology (DRO's Structural, etc.)

Optical (interconnects, switching, etc.)

Radiation Hardening (all for long life)

In addition to the hardware support area, there is a

potential cost reduction approach which is emerging t-hat will

have implications on GEO platforms in the middle 90's. This is

the use of the Space Station and the associated space based

capabilities. While it is difficult to quantify at this point,

there appears to be potential savings for GEO platforms in the

following areas:

7-b2
Ford Aerospace &

Communications Corporation

o Deployment of large appendages at LEO

o Assembly of modular payloads at LEO that would be

difficult or impossible to package as one item in the STS

o Alignment of antennas in zero-G environment at LEO

o LEO Check-out of payloads prior to transfer to GEO

o Servicing of modularized payloads at LEO in the event of

a detected fault

o Space based fueling and transportation

During the study, servicing at GEO was also evaluated but it

was determined that for payloads out to year 2000 it was

unlikely that services at GEO would be available. It is

recommended that the economic viability of GEO servicing be

examined in detail.

7-b3
Ford Aerospace &

Communications Corporation

SECTION INDEX

Page

8.0 SYSTEM COMPARISONS (TASK 7) 8-1

8.1 OVERVIEW 8-1

8.2 PHYSICAL PARAMETER COMPARISON 8-2

8.2.1 Weight and Power for All Scenarios 8-2

8.2.2 Weight and Power of Payloads used in Scenarios 8-3

8.3 SPECTRUM/ORBIT UTILIZATION 8-4

8.3.1 Bandwidth and Reuse 8-7

8.3.2 Modulation Efficiency 8-8

8.3.3 Throughput Comparison 8-8

8.3.4 Utilization Factor Comparison 8-9

8.4 COST COMPARISONS 8-9

8.4.1 Payload Costs 8-9

8.4.2 Space Segment Costs 8-10

8.4.3 Transponder Cost per Year Comparison 8-14

8.4.4 Alternative Approach Cost Comparison 8-15

8.5 GROUND SEGMENT IMPACT 8-17

8.5.1 Ground Segment Cost Estimates 8-17

8.5.2 Ground Segment Cost Comparison 8-18

8.6 OVERALL RANKING OF SCENARIOS 8-20

8.7 ASSESSMENT OF PROBABILITY OF IMPLEMENTATION 8-22
Aerospace &

Communications Corporation

8.0 SYSTEM COMPARISONS (TASK 7)

8.1 OVERVIEW AND SUMMARY COMPARISON OP SCENARIOS

The purpose of Task 7, System Comparison, is to provide an

evaluation of the benefits, advantages, disadvantages and

probability of implementation as well as ranking of the

communications payloads defined in the study. The approach used

by Ford Aerospace incorporated the following inputs:

o From Task 4: Candidate definitions

o From Task 5: Corresponding cost assessments for each

payload definition

o From Task 6: Corresponding critical technology

requirement for each payload definition

The following evaluation criteria were considered in order to

assess the overall benefits of each candidate scenario:

o Frequency spectrum utilization

Bandwidth

Re-use

.Modulation efficiency

o Inter-system interference

o Communications service reliability and availability

o Growth potential/flexibility

o Complexity (risk)

o Percent payload capacity utilization

o Compatibility with plant-in-place spacecraft and ground

segment equipment forecasted for 1998

o Cost assessment

A discussion of some of the evaluation criteria and the

scenario rankings are highlighted in what follows:

8-1
Aerospace &

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8.2 PHYSICAL PARAMETER COMPARISON

8.2.1 Weight and Power for All Scenarios

Table 8.2-1 provides a summary of the weight and power for

scenarios II, IV and V, and Table 8.2-2 is the same for

scenarios VI-A and VI-B. Included in the estimates are the

coax, waveguide, and harness interconnects, plus an estimate for

integration hardware to put the components together and provide

necessary brackets for support and mounting. Not included are

any structure or satellite mounting hardware such as between the

feed and reflector. Both tables are based on projected (high

risk) technology. It is anticipated that Table 8.2-1 payload

could fit launch concept 1 and Table 8.2-2 payloads would fall

into launch concept 2. Table 8.2-2 payloads would also require

some LEO assembly due to the number of reflectors.

Table 8.2-1

Characteristics of Scenario Payloads Using Projected Technology

(Integration Hardware Included)

Payload

C-Band FSS

Scenario II Scenario IV Scenario V

Wt(kg) Pwr(W) Wt(kg) Pwr(W) Wt(kg) Pwr(W)

89 659 246 708

Ku-Band FSS 261 2522 605 5075 523 785

Ku-Band DBS 223 3876 1012 29960

Ka-Band 1492 5933 1492 5933

TOTAL SCENARIO 2065 12990 1617 35035 2261 7426

8-2
Ford Aerospace &

Communications Corporation

Table 8.2-2

Characteristics of Scenario Payloads Using Projected Technology

(Integration Hardware Included)

Payload

C-Band FSS(Domestic)

C-Band FSS(Int'l)

C-Band FSS(Non-CONUS)

Scenario VI-A Scenario VI-B

Wt(kg) Pwr(W) Wt (kg) Pwr(W)

246

750

708

2166

574 1903

Ku-Band FSS(CONUS)

Ku-Band FSS(Non-CONUS)

523 785 523

186

785

1796

Ka-Band FSS(CONUS) 1492 5933 1492 5933

Maritime 79 649 44 649

Inter Satellite Links 111 160 107 131

TOTAL SCENARIO 3201 10401 2926 11197

8.2.2 Weight and Power of Payloads used in Scenarios

Table 8.2-3 provides a summary of the weight and power

required by each of the 16 different .payload elements used in

the five scenarios based on projected (high risk) technology.

Table 8.2-4 is the same breakdown using emerging (low risk)

technology. Use of the low risk technology would make scenario

V and possibly scenario II exceed the single shuttle to GEO

capability without fuel servicing or augmented perigee boost.

8-3
Ford Aerospace &

Communications Corporation

Table 8.2-3

Weight and Power of Payload Elements Using High Risk Technology

Payload Element

C-Band FSS(2 x reuse)

C-Band FSS(4 x reuse)

C/L Band Maritime

C/L Band Maritime

C-Band Intn'l(9 x reuse)

C-Band Non-CONUS(9 x reuse)

Ku-Band FSS(3 x reuse)

Ku-Band FSS(3 x reuse)

Ku-Band FSS(9 x reuse)

Ku-Band Non-CONUS

Ku-Band DBS(no reuse)

Ku-Band DBS(4 x reuse)

Used in

Scenarios Weiqht(kq)

II

V. VI -A

VI -A

VI -B

VI -A

VI -B

II

IV

V. VI-A. VI-B

VI-B

II

IV

89

246

79

63

750

574

261

605

523

186

223

1012

Power (W)

659

708

649

649

2166

1903

2522

5075

785

1796

3876

29960

Ka-Band FSS(CONUS) II. V. VI-A. VI-B 1492 5933

60 GHz Inter-Sat

60 GHz Inter-Sat

VI-A

VI-B

111

107

160

131

8.3 SPECTRUM/ORBIT UTILIZATION

The comparison of spectrum/orbit utilization among payload

concepts is complicated because regulatory issues as well as

technical ones are involved.

The FCC intends to address this matter in a future

proceeding, but it has developed an interim solution so that

potential benefit of hybrids can be demonstrated in actual

operation at the earliest practical date. It believes that if

2 spacing intervals are generally utilized, then maximum

8-4
Aerospace &

Communications Corporation

Table 8.2-4

Weight and Power of Payload Elements Using Low Risk Technology

Payload Element

C-Band FSS

C-Band FSS

C/L Band Maritime

C/L Band Maritime

C-Band International

C-Band Non-U.S.

Ku-Band FSS

Ku-Band FSS

Ku-Band FSS

Ku-Band Non U.S.

Ku-Band DBS

Ku-Band DBS

Ka-Band FSS

Ka-Band Scan

60 GHz Inter-Sat

60 GHz Inter-Sat

Used in

Scenarios Weiqht(kq) Power(Watts)

II

V. VI -A

VI-A

VI-B

VI-A

VI-B

II

IV

V. VI-A. VI-B

VI-B

II

IV

II. V. VI-A. VI-B

II. V. VI. VI-B

VI-A

VI-B

121

327

105

63

987

745

315

751

812

301

278

1227

2007

2007

147

140

922

1001

855

855

3140

2704

3444

7052

1164

2751

4554

34060

6849

6849

285

224

efficiency of orbital arc in both C and Ku-band is achieved

under current circumstances. The FCC sees an urgent need to

authorize without protracted administrative delays additional

domestic satellite capacity to satisfy growing demand. Based on

its present policy and precedents, the FCC has already made a

tentative orbit deployment plan. A description of which was

published in the July 29. 1985 issue of Satellite News. From

8-5
Ford Aerospace &

Communications Corporation

this article it is clear the C-band arc is saturated and the

Ku-band arc is heavily committed. This allocation made the new

orbital slot assignments in order to bring C-band satellites

into conformity with the FCC's 2 spacing order of April 1983.

These proceedings and the results of international frequency

coordination and future international conferences are likely to

affect how each payload concept is to be implemented.

Projection of regulatory issues concerning the 1998 era has

its uncertainties. Ford Aerospace's approach here is to analyze

the likelihood of each spectrum/orbit allocation associated with

the payload concept based on last and current policy philosophy

of FCC and WARC-79.

Since most payload concepts in this study include a mixture

of the C. Ku. and Ka-bands. some difficulties may arise because

of the -different orbital spacing criteria currently used by FCC

for different bands.

On the technical aspects. the geostationary orbit's

well-known attractiveness is that it alleviates satellite

tracking and acquisition problems and eliminates the need for

routine satellite handover. A majar drawback is that coverage

in the polar area is not provided, and users operating in the

higher northern latitudes view the satellite at very low

elevation angles. Low elevation angles induce a host of

problems to users such as:

o Refractive index anomalies

o Interference with other terminals

o Probability of detecting signals radiated by other

terminals

8-6
Ford Aerospace &

Communications Corporation

Although this study concerns mainly CONUS users, there are

cases involving low-elevation-angle users. For payload concepts

involving such cases, there is a higher ground segment cost

impact because earth station requirements are more strict with

respect to such performance parameters as EIRP and sidelobes.

8.3.1 Bandwidth and Reuse

A comparison of the effective bandwidth provided for each of

the five scenarios is shown in Table 8.3-1.

Table 8.3-1

Effective Bandwidth (GHz)

Communication

Band

Ka

Ku (FSS)

Ku (DBS)

C

L

Scenario

II IV V VI-A VI-B

30.3 — 30.3 30.3 30.3

1.3 1.2 3.9 3.9 5.2

.4 1.5

.9 -- 1.7 5.6 3.

.035 .035

ISL -- — — 4.5 3.0

8-7
Ford Aerospace &

Communications Corporation

8.3.2 Modulation Efficiency

The modulation efficiences used in the traffic loading ace

identified in Table 8.3-2 and the types of modulation by payload

ace shown in each of the transponder loading pcintouts pcovided

in the Addendum to the final cepoct.

Table 8.3-2

Summacy of Modulation Capacity Assumptions

Modulation Technique Capacity (36 MHz)

8 PSK 72 Mb/s

CSSB 6000 HVC

FDM/FM 2800 HVC

SCPC 1800 HVC

Video-FM

SQPSK (ISL)

2.5 Channels

1.5 Gb/s

pec ISL channel

8.3.3 Thcouqhput Compacison

The throughput by payload element foe the four communications

scenacios is shown in Table 8.3-3. The fifth scenario, scenario

IV. is a video distribution satellite and does not lend itself

to this compacison.

8-8
Ford Aerospace &

Communications Corporation

Table 8.3-3

Maximum Throughput (Gb/s) By Scenario

Application

Ka-Trunking

Ka-CPS

Ku-FSS

C

ISL

Total

Scenario

II V VI -A

49.9 49.9 49.9

8.6 8.6 8.6

5.2 15.6 15.6

3.5 6.9 14.2

4.5

67 81 93

VI-B

49.9

8.6

17.5

5.7

3.0

85

8.3.4 Utilization Factor Comparison

The development of the utilization factor for each of the

communications payloads is discussed in Section 4.8.5 and

summarized in Table 8.3-4. As can be seen, the factors only

vary from 0.756 to 0.774.

8.4 COST COMPARISONS

8.4.1 Payload Costs

The payload costs were prepared from a component basis as

described in Section 6. Table 8.4-1 provides a payload by

scenario cost and total cost for each scenario.

8-9
Ford Aerospace &

Communications Corporation

Table 8.3-4

Summary of Utilization

Application

II

Scenario

Vl-A VI-B

Ka Trunking

Ka-CPS

Ku (U.S-FSS)

Ku (Non-U.S.)

C (U.S.)

C (International)

C (Non-U.S.)

ISL

Weighted Average

.76

.76

.62

-

.92

-

-

.760

.76

.76

.83

-

.62

-

-

—

.765

.76

.76

.83

-

.62

.61

-

.84

.756

.76

.76

.83

.81

-

-

.75

.70

.774

8.4.2 Space Segment Costs

In order to compare platforms against the current method of

providing services with multiple satellites, a total space

segment cost was necessary. A 'number of assumptions were made,

as shown in Table 8.4-2. to arrive at a total space segment

cost. The launch cost for transportation to GEO was estimated

based on the Rockwell study results shown in Figure 8.4-1. This

curve assumes that for payloads that are larger than a single

STS can lift in one mission, fueling at LEO would be provided at

the same marginal cost as the last pound of lifted payload on

the STS is provided. This allows the dry platform to be fueled

at LEO and the STS only has to lift the dry platform weight for

launch. This approach applies to scenarios VI-A and VI-B and

may be required for scenario V.

8-10
Ford Aerospace &

Communications Corporation

Table 8.4-1

Projected Costs of Payload Elements ($M)

Payload Element

C-Band. FSS

C-Band. FSS

C/L-Band Maritime

(Atlantic)

C/L-Band Maritime

(Pacific)

C-Band. Internal '1

C-Band. Non-U.S.

Ku-Band. Non-U.S.

Ku-Band. FSS

Ku-Band. FSS

Ku-Band. FSS

Ku-Band. DBS

Ku-Band. DBS

Ka-Band, FSS

Ka-Band, SCAN

60 GHz, ISL

TOTAL

§

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II § IV

§

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Following Scenarios

V § VI-A § VI-B

§

§

§

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7.9 § 7

§

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8-12
Ford Aerospace &

Communications Corporation

Table 8.4-2

Cost Assumptions

o No development costs are included.

o Spacecraft weight allocation at beginning of life (BOL)

Payload 31%

Bus 47%

Stationfceeping fuel (10 yrs) 22%

o Bus Costs

For large S/C: $40 million recurring + $20 million

for integration and launch operations.

For very large S/C: $60 million recurring + $30

million for integration, launch, and LEO operations,

o Perigee and apogee stage costs are included in launch

costs.

o Use of Rockwell study for estimating launch costs:

launch COSt($M) = 44.6 Ln (BOL Wt Ibs) - 293.2

Using the bus cost assumptions and the estimated launch cost,

the total space segment cost for each scenario was derived, as

shown in Table 8.4-3.

Table 8.4-3

Comparison Costs (1984 $M)

Recurring

Scenario Payload Bus Launch

II 81 60 134 275

IV 67 60 123 250

V 90 60 138 288

VI-A 126 90 154 370

VI-B 132 90 150 372

8-13
Ford Aerospace &

Communications Corporation

8.4.3 Transponder Cost per Year Comparison

In order to use the above space segment costs for comparison

to today's provided services, each scenario cost was converted

to cost per 36 MHz bandwidth per year, as shown in Table 8.4-4.

This led to a transponder cost from 26 to 32K dollars per year.

It must be noted that the 26 to 32K dollars does not include any

profit for the manufacturer. operating costs. recovery of

non-recurring, or profit for the operator. It is reasonable

that the cost to the user would be at least double the recurring

cost. Thus, the lease cost to a user would be 52 to 64K dollars

per year which still appears attractive compared to the 190K to

280K dollars per year shown in Table 3.3-1 as estimated prices

for 1982 to 1987 time frame. Thus, a factor of 4 or 5 to one

reduction in transponder lease costs could be recognized based

on an aggregated platform payload compared to todays costs.

Table 8.4-4

Transponder Costs Per Year

SCENARIO

COMMUNICATIONS I_I V VI-A VI-B

•

Cost/Satellite ($M) 237*1 288 370 372

EFF B/W (GHz) 32.5 35.9 44.3 42.4

Cost/36 MHz/Year ($K)*2 26 29 30 32

VIDEO CHANNELS II IV

Cost/Satellite ($M) 38*1 250

No. Channels 16 112

Cost/24 MHz/Year ($K)*2 238 223

**• Bus and launch costs prorated, based on payload costs

for DBS and communications.

*

2 10 year life

8-14
Ford Aerospace &

Communications Corporation

8.4.4 Alternative Approach Cost Comparison

Using each scenario as a baseline for comparison, and

estimating the number and recurring cost of current day

satellites to provide equivalent band width, then adding the

launch cost for the current day satellites from the Rockwell

study, a total cost of providing the equivalent service by

individual current day satellite was derived. Table 8.4-5

presents the comparison of these numbers for evaluation. It can

be seen that the aggregated payloads are 4-5 times less

expensive. This is equivalent to the reduced per transponder

costs shown in Table 8.4-4.

Table 8.4-5

Alternative Approaches To Providing Equivalent Capacity

SCENARIO II

($237M)

Payload

C - 24 @ 36

Ku - 24 @ 54

Ka - 52 @ 500

18 @ 240

•Equivalent"

Satellite

SATCOM

GTE

HUGHES

32 X 160 MHZ

Number

Required

1

1.6

5.9

Costs ($M)

(Satellite + Launch)

40 + 35

50 + 35

90 + 75

TOTAL COST $1L85M

SCENARIO V

($287M)

Payload

"Equivalent"

Satellite

C - 48 & 36 SATCOM

KU - 108 @ 36 GTE

Ka - 52 @ 500 HUGHES

18 @ 240

Number

Required

Costs ($M)

(Satellite + Launch)

2

4.8

5.9

TOTAL COST

8-15

40 -i- 35

50 + 35

90 + 75

$1531M
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Table 8.4-5

Alternative Approaches (Continued)

VT-A

($370M)

Payload

C= 48 @ 36

Ku - 108 <P 36

Ka - 52 @ 500

18 (P 240

C - INT'L

C/L

"Equivalent"

Satellite

SATCOM

GTE

HUGHES

I-VI

INMARSAT

Number

Required

2

4.8

5.9

2

1

TOTAL COST

Costs ($M)

(Satellite + Launch)

40 + 35

50 + 75

90 + 75

65 + 75

35 + 35

$1881M

SCENARIO IV-B

($372M)

Payload

"Equivalent"

Satellite

Number

Required

Costs ($M)

(Satellite + Launch)

KU - 108 & 36 GTE

Ka - 52 @ 500 HUGHES

18 @ 240

4.8

5.9

50 -t- 35

90 + 75

Domestic

Canada

Mexico

Brazil

Other LAM/C

ANIK 2

MORALES 1

BRAZILSAT 2

PAN AM SAT 1

40 + 35

30 -i- 35

40 + 35

40 + 35

C/L INMARSAT

TOTAL COST

35 35

$1901M

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8.5 Ground Segment Impact

The degree by which satellite service aggregation affects the

terrestrial communication system of the 1990s is dependent to a

large extent upon the performance enhancement provided by this

new utilization of technology. As a minimum it will overcome

the growing problem of orbital arc saturation and permit greater

utilization of satellite resources both within the United States

and in the Third World countries of Central and South America.

This in turn will greatly increase the number of earth terminals

as the benefits of satellite communications are spread

throughout the Western Hemisphere.

Within the United States the effect may be less pronounced,

due to a larger portion of the traffic being carried by fiber

optic cable systems and expanded local area networks. However,

international traffic, thin route regional traffic, and direct

broadcast services are areas sensitive to potential expansion.

Increases in platform reflector sizes and/or transmit power

would reduce terminal requirements and, coupled with technological advances in LSI digital circuitry and solid-state

receivers and amplifiers, would substantially reduce the cost of

individually owned terminals. This cost reduction coupled with

the desire for increased services such as provided by direct

broadcasting, for example, could cause major growth in satellite

telecommunication services offered via geostationary platforms.

8.5.1 Ground Segment Cost Estimates

Table 8.5-1 provides an estimated cost for a particular

frequency and size (type) of service. A number of factors

affect the actual terminal cost, such as availability (on line

redundancy vs. sparing), environment (wind, sun, temperature,

etc.), and location (edge of beam, low elevation angle, etc.);

thus only ranges of costs by frequency band could be provided.

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Table 8.5-1

Estimated Cost Of Earth Terminals

Type Recurring Cost

C-band

10m - 15m (Tx. Rx) $200 - $1000K

2m - 8m (Tx. Rx) $10K -50K

2m - 5m (RECEIVE ONLY) $2K - 10K

Ku-band

7m -10m (TDMA. Tx. Rx) $150K -500K

2m - 3m (FDMA. Tx. Rx) $4K -5K

1m (DBS. RECEIVE ONLY) $0.4K -0.6K

Ka-band

5m -7m(TDMA. Tx. Rx) $250 - 300K

2m -3m (TDMA. Tx. Rx) $100K -170K

Also, the. type of modulation and access have effects on the

terminal cost. It was assumed that C-band would remain primarily

an FM (analog) system, and the digital systems used at Ku and

Ka-bands, with TDMA used at Ka-band.

8.5.2 Ground Segment Cost Comparison

Although actual cost comparison of ground segment costs are

almost impossible without a hypothesized system, it is clear

significent cost saving will be recognized for the large

platforms in the trunking application. For comparison purposes,

assume a Scenario V satellite replaces its equivalent capacity;

i.e.. 12.7 satellites. In this instance there are three

frequency bands; therefore, a given terminal location to operate

with total connectivity would require only 3 antennas as opposed

to 13 for the equivalent employment of satellites. While it is

not clear precisely what actual population of terminals would be

required, a look at the current ratios for the Intelsat network

is useful. It is estimated that approximately 40% of the

- - 8-18
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locations require total connectivity: about 30V more require 2

of 3, and only 30% have one antenna for the trans-Atlantic

satellites. This, of course, is very traffic sensitive from a

distribution standpoint. However, usinq these numbers, and the

costs from Table 8.5-1, an equivalent normalized cost for total

interconnectivity can be calculated. Table 8.5-2 shows the

resultinq equivalent cost for a qiven location, which requires

an equivalent 8.15 ground terminals at an equivalent price of

$2.965.000, as opposed to the 3 terminals, 1 C-band ($600K).l

Ku-band ($325K). and 1 Ka-band ($275K). at an equivalent price

of $1,200.000, or rouqhly 40% of the cost.

Table 8.5-2

Scenario V Equivalent Ground Costs

Band

C-Band

Ka-Band

For Total Interconnectivity

%

Term.

Rea 'd.

70%

30%

40%

30%

30%

40%

30%

30%

No. of

Term.

Req 'd.

2

1

4 or 5 (4.5)

2 or 3 (2.5)

1

5 or 6 (5.5)

3 or 4 (3.5)

1 or 2 (1.5)

Equiv.

# of

Term.

1.4

.3

1.8

.75

.30

2.20

1.05

.45

Avg.

Cost of

Term. ($K)

600

600

325

325

325

275

275

275

Equiv

Cost

Term.

840

180

585

244

98

605

289

124

Of

($K)

TOTALS 8.15 2.965

The costs derived above are on a per node basis, and if an

extensive network is envisaged, the savings in ground costs

could be extensive, roughly $1.7M per node. While this estimate

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does not consider that multiple terminals at a single location

should not cost the multiple times the per station cost, if a

30% savings per station were recognized, the savings per node

would still be $875K. This comparison is only for one Scenario

V satellite and its equivalent satellite complement. If the

total complement of eight satellites were all to be

interconnected, the numbers escalate as a squared function and

really multiply rapidly.

8.6 OVERALL RANKING OF SCENARIOS

As with our prior evaluations, the five Scenarios were ranked

against each other and no ties were allowed. The criteria

ranked were the criteria established in Task l. Table 8.6-1

presents the results of this ranking. Scenario V ranks the

highest, and Scenario VI-A and VI-B tie for the lowest ranking.

Table 8.6-2 then provides the key features and the advantages of

each of the Scenarios.

Table 8.6-1

Ranking Of Payload Scenarios

Payload Concept Scenario

Criteria II IY V VI-A VI-B

Bandwidth-Reuse 45 3 1 2

Modulation Efficiency 45 1 2 3

Interference 21 3 4 5

Reliability/Availability 21 3 4 5

Growth 21 1 1 2

Complexity 21 3 5 4

Utilization 43 2 5 1

TOTAL ~2Q 17 I? 22" 22~

RANKING 3- 2 1 4 + 4 -

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Table 8.6-2

Overall Ranking Of Scenarios

1 SCENARIO V (HIGH CAPACITY CONUS)

Optimized to CONUS FSS distribution

All Rigid Reflectors

Seven satellite constellation satisfies

demand through 2008

Limited barriers

2 SCENARIO IV (HIGH CAPACITY DBS)

Single location for multiple users

Minimizes ground assets

FSS payload tailored to DBS

On-board networking

3 SCENARIO II (MEDIUM CAPACITY CONUS) ' "

Replacement of mid-90's payloads

High capacity digital Ka-band

Poor analog balance for CONUS (87% digital)

No major barriers (orbital location restricted)

4+ SCENARIO VI-A (INTERNATIONAL TRAFFIC)

--Highest throughput scenario

Lowest utilization/capacity

Major institutional barriers

Suitable for integration with scenarios V and VI-B

4- SCENARIOS VI-B (NON-CONUS DOMESTIC)

Efficient use of orbital arc

Extremely difficult institutional barriers

Suitable for integration with scenarios V and VI-A

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8.7 ASSESSMENT OF PROBABILITY OF IMPLEMENTATION

In summarizing the comparisons, an assessment of the

probability of implementation was also evaluated. It seems

likely that a platform similar to Scenario V is a very probable

payload to be implemented. It requires that there is a sizeable

growth in the market to warrant the large capacity, and that the

development of the Ka-band ACTS hardware reduces the risk of use

to an acceptable level for commercial implementation. The use

of the Ka-band payload is one of the largest contributions to

the reduction in per channel cost.

Scenario IV. while ranked second, may actually be the most

likely scenario to be developed. This scenario is probably the

most technically sound application of satellites. Yet it faces

resistance from the extensive plant-in-place in the U.S.. and as

a result, the DBS industry has been faltering in getting started.

Both Scenarios IV and V are capable of implementation within

the regulatory bounds of the U.S.. and both could be operated by

a single entity.

It is not likely that a Scenario II satellite would be

implemented as the Ka-band digital capacity is too large

compared to the analog capacity, and the DBS package limits the

potential orbital locations.

The remaining two scenarios. VI-A and VI-B. while technically

a very sound and efficient use of the arc. would be nearly

impossible to implement due to; the number of users involved,

the international coordination of governments, the necessary

licenses. and nationalistic considerations. The extent of

political coordination. and the commonality of system

implementation over currently diverse systems, make it unlikely

these platforms could be implemented.

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SECTION INDEX

Page

9.0 SUMMARY/RECOMMENDATIONS 9-1

9.1 OBJECTIVES ACCOMPLISHED 9-1

9.2 ANSWERS TO STUDY QUESTIONS 9-2

9.3 RECOMMENDED FUTURE ACTIONS 9-3
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9.0 SUMMARY/RECOMMENDATIONS

9.1 OBJECTIVES ACCOMPLISHED

The specific goals of the Communications Platform Payload

Definition Study were as follows:

o Determine types of geostationary communications payloads

applicable to a large platform, circa 1998.

o Provide concept system architecture.

o Provide payload concept and description.

o Provide comparisons, including estimated cost and technology risk.

o Identify high payoff technology.

All of the above objectives were accomplished. Four of the

five scenarios developed demonstrate the capability of

significantly reducing the number of required orbital locations

to satisfy all of the projected WARC Region 2 satellite

communications traffic through the year 2008.

Although the results of this study must be considered

preliminary, certain conclusions can be drawn:

o Large platforms may provide significant economies of

scale,

o Scenarios VI-A and VI-B can serve all Region 2 non-U.S.

year 2008 traffic with one platform of each type,

o A constellation of seven Scenario V. or combinations of

Scenarios V. VI-A and VI-B. could serve all U.S.

satellite traffic, with the exception of broadcast video.

in the year 2008.

o Major institutional. regulatory and insurance issues.

exist, especially for Scenarios VI-A and VI-B.

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Given the apparent economies of reduction in per circuit

cost, the platform warrants further effort, even given the

significant barriers to be addressed. The demand for efficient

utilization of the geostationary arc. and ultimately the

formation of a Region 2 communications organization, could lead

to implementation of these large platforms.

9.2 ANSWERS TO STUDY QUESTIONS

The study evaluates the impact of new traffic forecasts, and

estimates of new services to be provided, in order to provide

NASA guidance in answering the following questions:

o Is the existence of one or more large scale geostationary

facilities, each consisting of a payload. providing a

single communications service or a variety of

communications services, desirable in the raid to late

1990's?

o If so, what are the most viable operational systems

(payload. spacecraft, transportation, and space operations) for that time frame?

o For those operational systems, what enabling and

supporting technologies are required prior to

implementation. and. in particular. which of those

technologies is of high technical and/or economic risk?

The results of the study detailed in the prior sections of

this report provide NASA the following guidance in answering

the questions raised at the outset of the study:

o Economically and technologically, a constellation of

large geostationary facilities are desirable in the mid

to late 1990's. However, institutional and other factors

may be insurmountable barriers to implementation.

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o The most commercially viable payload would be similar to

the Scenario V payload. This payload can be replicated

as many times as necessary to satisfy the total CONUS

demand.

o The major payload technological risks are dual polarization reuse at Ka-band, high efficiency modulators and

demodulators, high speed programmable frequency shifters,

large rigid reflectors for high frequency dual polarization, lightweight on-board baseband processors and RF

equipment, and spacecraft bus technogies to support the

large platform.

9.3 RECOMMENDED FUTURE ACTIONS

During the study, a number of items that required further

study effort. as well as technology development. wer.e

identified. Among the more signifiant of these items were:

o The economics for using space station capabilities need

to be evaluated as they mature.

o Continued development of baseband processing capacity and

flexibilities as more direct to user systems are

implemented.

o The next step to continue the payload development is to

select a concept and institute detailed system implementation. The traffic distributional characteristics

need to be validated, and further optimization of the

antenna and transponder configuration should be performed.

o Subsequently. the integration of the payload to a

specific bus and transportation interface is required.

Then the specific platform is ready for hardware

development.

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Given the potential economic benefits, and the long term

need to minimize the number of orbital locations utilized, a

continued development of a large geostationary communications

facility is an appropriate application of national resources.

Even using the large capacity payloads defined in this study,

assuming that only 50 orbital slots are available to CONUS. and

that traffic will double every 10 years, the orbital arc will

be saturated before 2030; thus, there is a continuing need to

increase capacity per orbital location in the long term, and

the proliferation of small satellites will not make economic

sense.

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REFERENCES
Ford Aerospace &

Communications Corporation

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Ford Aerospace &

Communications Corporation

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R-2
Ford Aerospace &

Communications Corporation

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Ford Aerospace &

Communications Corporation

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Ford Aerospace &

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Ford Aerospace &

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