# Presentation: 208665

## NASA Infrastructure Capabilities  to Support Near-Earth Missions

**16 July 2002**

## Purpose of Briefing

***Purpose of Briefing***

**Identify existing NASA and commercial ground and space capabilities**
**Identify the constraints associated with use of the current allocated spectrum **
**Define possible architecture for communications support to future earth science high data rate missions**
**Identify available technology to support future high data rate missions operations at Ka-band**

## Background

***Background***

**Future near-earth science missions want:**
- Higher data rates for space-to-ground data transfer
- Minimize data latency
- Lower cost communications subsystems with reduced size and weight
**Availability of adequate RF spectrum to support these goals is of significant interest because of:**
- Increasing RF congestion in allocated bands (S, X, and Ku-bands)
- Continuing increase in mission downlink data rate requirements beyond capacity of existing allocations

## Infrastructure Overview

- Earth Exploration Satellite (EES) data communications can be accomplished via:
- Direct link with a ground terminal, such as NASA’s Ground Network (GN)and/or
- Through a relay satellite system, such as NASA’s Tracking and Data Relay Satellite System (TDRSS)
- Infrastructure to support these services can be provided through several sources, such as:
- Government resources, such as the Ground Network and TDRSS
- Commercial resources, such as Datalynx and Universal SpaceNet
- Mission-dedicated ground terminal

## Ground Network

**Wallops Island**

**McMurdo Station, Antarctica**

**Poker Flat, Alaska**
**DATALYNX**

**University of Alaska,**
**Fairbanks**

**Svalbard, Norway**
**NSC**

**Merritt Island,**
**Ponce De Leon**

**Santiago**
**U of Chile**

**USN**

**USN**

**USN**

**USN**

**USN**

**Hawaii**

**Perth**

**South Africa**

**Sweden**

**Ground ****Network**

## Available X-band Ground Network Infrastructure Summary

-                               List may not be all encompassing (i.e., does not include DSN stations as well as other all foreign stations)

## NASA’s Space Network

**TDRS Constellation**

**F-5**
**174°W**
**TDW**

**F-7**
**171°W**
**(in-storage)**

**F-6**
**047°W**
**TDS**

**F-4**
**041°W**
**TDE**

**F-3**
**275°W**
**TDZ**

**WHITE SANDS COMPLEX**

**GODDARD SPACE FLIGHT CENTER**

**GUAM REMOTE  GROUND  TERMINAL**

**TDRS- F8**
**171°W**

- 	TDRS-I undergoing transfer orbit correction
- 	TDRS-J scheduled for launch late 2002
- The SN is composed of the Space Segment, consisting of the Tracking and Data Relay Satellites (TDRS), and the Ground Segment, consisting of ground stations located in White Sands, New Mexico and Guam and other supporting subsystems.

## NASA’s Space Network Capabilities

## Infrastructure/Spectrum Allocation Summary

| Frequency Band | Ground Network (GN) | Space Network (SN) |
| --- | --- | --- |
| S-band
 | 90 MHz EES downlink allocation.  Spectrum pressure to limit bandwidths to 5-7 MHz per mission
Available resources
Insufficient for wideband service |  90 MHz return allocation
 Available resources
 Insufficient for wideband service |
| X-band | 375 MHz for EES downlink; 50 MHz for SR downlink
Available resources
Getting crowded
Spectrum pressure to limit bandwidths to ~ 100 MHz EES; SR BW limited to 10 MHz |  No SN system capability |
| Ku-band | No allocation for EES; secondary for SR
WRC-03 proposing SR downlink primary allocation |  No EES allocation; secondary allocation 
   for SR
 Available resources
 Maximum 300 Mbps supported |
| Ka-band | 1.5 GHz EES downlink
No existing resources
Leverage NASA technology developments and commercial ground equipment  | 2.25 GHz return (intersatellite allocation)
TDRS F8 operational, F9 - orbit raising maneuvers, F10 - launch in Fall 2002
Satellite supports 225 and 650 MHz return BW  
KaTP developing IF service to support 650 MHz return; can leverage NASA technology developments and commercial grd. equip.  |

## Current and Projected X-Band Missions Using Polar Ground Station Resources

## Future High Data Rate EES Missions

**Earth Orbital**

**Mission**

**Code**

**Data Transfer Req.**

**Orbit**

- Missions

- Per

- Timeframe

- S/C Per

- Mission

**Description**

**MID TERM MISSIONS(2010-2015)**

**Earth Orbital**

**NEAR TERM MISSIONS(2005-2010)**

**Earth Orbital**

## Current Ka Frequency Allocations

**INTER-SATELLITE SERVICE **

**25.25 GHz**

**Ka-Band Allocations for TDRS H,I,J Return Service and Direct-to-Ground Communications**

** **

- 27 GHz

**27.5 GHz**

- 25.5 GHz

**EARTH-EXPLORATION SATELLITE SERVICE (s-e)**

***Current Ka Frequency Allocations***

**NASA spectrum managers encouraging medium and high data rate, near-earth missions to utilize RF allocation at Ka-band**
- Supports higher data rates due to larger space-to-earth allocation for earth-exploration satellites
- Allows smaller, lighter spacecraft components (e.g., antennas)
- Affords missions the flexibility of using a wide bandwidth space-to-space link via the TDRS H,I,J Ka-band service (backup support)

**NOTE:**
**The addition of a primary allocation for Space Research Service in the 25.5 - 27.0 GHz band will be considered at the next World Radio Conference (WRC) in 2003.**

## X-Band  vs. Ka-Band Comparison

## X-Band  vs. Ka-Band Comparison (cont’d)

## Possible Ka-Band Ground Terminal Configuration

***Possible Ka-Band Ground Terminal Configuration***

**Possible Ka-band configuration to support high-inclination, near-earth spacecraft**
- Co-locate Ka-band ground (receive only) station with existing S/X-band ground stations at high inclination sites (e.g., Alaska and Norway)
- Use existing S-band capability for TT&C, initially
- Cost savings through use of existing ground station infrastructure
- Use Ka-band receive capability for EESS data (up to at least 600 Mbps, initially)
- Provide hooks (e.g., link margin) for future addition of Ka-band downlink data rates greater than 1Gbps and S-band TT&C capability
**Possible Ka-band technical characteristics**
- 25.5 - 27 GHz frequency band
- BPSK and QPSK modulation, initially
- 5-meter class ground terminal antenna capable of supporting overhead passes
- Can support space-to-earth data rates from 600 Mbps - 1 Gbps for a 33 dBWi spacecraft EIRP
- On-site data storage and rate buffering (use T3 to offload data)

## Ka-Band Technology Considerations

**No new or high-risk technologies required for a ****Ka-band Ground Terminal (for downlink reception)**
**Technology developments at GSFC can be leveraged for space and ground Ka-band systems**
- Ka-Band Transition Project (KaTP) uses
- 5.4m S/Ka-band demonstration ground station located at WFF
- WSC modifications to support wide-band (650 MHz) KaSAR customers
- High data rate SN and GN demonstrations (600 Mbps)
- Ka Upconverter and Modulator (QPSK, 150 Mbps)
- Ka-Band Phased Array S/C Antenna (33 dBWi EIRP)
- High Data Rate Parallel Digital Ground Receiver (QPSK, 600 Mbps)
- High Data Rate Digital Modulator (multiple modulations, 1 Gbps)

## Ka-Band Technology Considerations (cont’d)

**GSFC contacted commercial vendors to assess the availability of Ka-band **_**spacecraft**_** hardware**
- Solicited information (RFI) for a high rate spacecraft modulator (600 Mbps using QPSK, 800 Mbps using 8PSK)
- Responses received from several manufacturers (General Dynamics, L-3 Communicaitons, Rockwell Corp, Northrup Grumann)
- Cost to complete current General Dynamics BB design is on the order of $1M/1 year for a 600 Mbps capability
- Space qualified Ka-band upconverters and TWTAs/SSPAs have been developed by several manufacturers:
- Motorola, Lockheed Martin, Bosch, Thomson Tubes

## Candidate Ka-Band Ground Equipment Summary

***Candidate Ka-Band Ground Equipment Summary***

**5-Meter S/Ka-Band Antenna (including LNA):  $1.5M**
**Ka-Band Downconverter:  $80K**
**Low-Rate Receiver (up to 10 Mbps):  $140K**
**High-Rate Receiver (600 Mbps):  $0.9-1.0M**
**Data Storage System:  $750K**
**Monitor and Control System:  $225K**
**Facilities and Installation:  $500K**
**Project Mgmt., Sys. Engineering, Test/Verification:  $500K**
**Contingency: $250K**
**Total Ka-band ground terminal equipment < **$5M per site

***NOTE: Hardware costs are rough estimates and assume the implementation of a single antenna, and prime and redundant equipment chains.***

## Summary

**The goals for future near-earth science missions include:**
- Higher data rates (up to 1 Gbps) for space-to-ground
- Minimize data latency
- Lower cost communications subsystems with reduced size and weight
** ****X-band resources are available today, but **
- Band is becoming congested
- Spectrum pressures to limit mission bandwidths may prove extremely difficult to meet future wideband downlink requirements
**Ka-band will meet future wideband downlink requirements**
- Ka-band infrastructure is available through the NASA TDRS (F8 operational)
- Ka-band technology developments show that Ka GN is a viable solution

## Back-Up Slides

## Recent Spectrum Issues

**The following spectrum management actions must be considered in the design of future missions  **
- SFCG is considering the channelization of the X-band Earth Exploration Satellite Service (EESS) allocation to facilitate band sharing among increasing number of missions.  Also, SFCG is considering an upper limit on bandwidth utilization by any single mission for both S- and X-bands.
- International space standards organizations have developed bandwidth efficient modulation recommendations for S-band and X-band
- NTIA defines a spectral mask for all space services operating above about 1 GHz

## NASA’s Ka-Band Transition Product

**The Ka-Band Transition Project (KaTP) was initiated by NASA/GSFC in the fall of 1999 as a first step in transitioning the SN and GN to Ka-band operations**
**The KaTP is a technology development, integration, and demonstration initiative to facilitate the transition of SN and GN users to allocated Ka-band frequencies**
- Develop a new SN IF service using the TDRS H,I,J 650 MHz channel
- Develop a GN demonstration system to demonstrate GN Ka-band operations and provide for future commercialization
- Provide a test bed within the SN and GN to demonstrate new communications technologies
- bandwidth efficient modulations
- high data rate receivers
- data processing/storage devices
- Provide the impetus and confidence to flight and ground system customers by demonstrating candidate Ka-band solutions

## KaTP Overview

**Space Network Segment**
- Upgrade the SN ground stations at WSC and modify NCC software to take advantage of the new TDRS H,I,J spacecraft’s 650 MHz Ka-band space-to-space return link in the 25.25 GHz to 27.5 GHz band
- Provide an IF output compatible with the GN implementation
- Frequency support capability in accordance with SNIP agreements
**Ground Network Segment**
- Implement a demonstration ground terminal for the GN at Wallops Flight Facility to support direct-to-ground links in the 25.5 GHz to 27 GHz band
- Provide an IF output compatible with the SN implementation
- S-Band support for command and health/safety telemetry

## Ka-Band Transition ProjectHigh Data Rate Demonstrations

**KaTP high data rate demonstration will utilize the new equipment implemented within the SN and the new ground station implemented within the GN to:**
- Characterize the performance of the physical return links at rates up to at least 600 Mbps
- GN: Direct-to-earth Ka-band downlink
- SN: return Ka-band link relayed via TDRS H
- Characterize the acquisition and tracking performance of the GN Ka-band antenna
- Assess the effects of hardware distortion on the overall link
- Characterize the GN and SN system designs
- Provide an end-to-end system (i.e., “reference link” or test system) to help characterize new high rate Ka-band hardware.
**The demonstrations will assess the RF link performance via measurements of bit error rate and the signal spectra**
**SN demonstrations are currently scheduled for the September 2002 timeframe **

## Ka-Band Link Budget

## Ka-Band Ground Terminal - Reference Architecture (S- & Ka-Band)

***Ka-Band Ground Terminal - ******Reference Architecture (S- & Ka-Band)***

**S-Band Equipment**

**S-Band **

**Diplexer**

**LNA and**

** **

**switches **

**Telemetry **

**Receiver**

** **

**Equipment**

**Nominal 5 Meter Antenna**

**Telemetry **

**Downconverter**

**S-band **

**HPA**

**S-band **

**Exciter**

**Command  **

**Modulator**

**Tlm/Cmd**

** **

**Baseband **

**Processor**

**S/Ka-Band Antenna Assembly**

**IF Switch**

**Ka**

**-Band  **

**Downconverter**

**Ground  Station Data **

**To/From Leased**

**  **

**Telecomm Service**

**Telecommunications  Interface**

**Ka-Band Equipment**

**Common Time **

**and Frequency  **

**Standard**

**Monitor and  **

**Control**

** **

**Subsystem**

- Status and Scheduling Data

**Antenna **

**Control  **

**Unit**

- Ant. Angle Data

- from Antenna Ctrl Unit

**Tracking **

**Processor**

**High Rate**

**  **

**Demodulator**

**Data Switch**

**Telemetry **

**Data Storage**

**Bit **

**Synchronizer**

**Decoder**

**Decoder**

**Bit **

**Synchronizer**

** ****RAID****Data Storage**

- Science Data to Customer MOCs/PIs

**Low Rate**

** **

**Demodulator**

- • Spacecraft Command

- • Housekeeping

-   Telemetry

- • High Rate

-   Science Data

**Data Switch**

**S-Band **

**Transponder**

**Ku-Band **

**Up **

**Converter**

**Ka-Band **

**Phased Array**

** **

**Antenna**

**Baseband **

**Data To/From **

**Spacecraft **

**Processor**

**Diplexer**

**S-Band **

**Antenna**

**Ka-Band **

**Up **

**Converter**

** ****Amplifier**

**Bandpass **

**Filter**

**NASA 4th Generation Transponder**

**LEO Spacecraft**

- Cmd Data

- Tlm Data

- Tracking Data

***Existing******Commercial******Site***

***- future capability***

## AGS 11 Meter Antenna Load

_**Missions Supported**_
- Aqua
- Aura
- EO-1
- IceSAT
- Landsat-7
- QuikSCAT
- TRACE

**8/1/01           1/1/02                     6/1/02               1/1/03              6/1/03                     1/1/04                              6/1/04                1/1/05**

## SGS 11 Meter Antenna Load

_**Missions Supported**_
- Aqua
- Aura
- EO-1
- IceSAT
- Landsat-7
- QuikSCAT

**8/1/01           1/1/02                     6/1/02               1/1/03              6/1/03                     1/1/04                              6/1/04                1/1/05**