NASA Technical Memorandum 102547

Advanced Launch System (ALS):

Electrical Actuation and=Power

Systems Improve Operability

and Cost Picture ..........

Gale R. Sundberg - 5 ii_ - ; u _ _ _- _i L iii

Lewis Research Center

Cleveland, Ohio

(NASA-TM-IOZSt_7) AqVANCEO LAUNCH SYSTEM Nq0-2!271

(AL_)" _LrCT_ICAL ACTUATION AND POWER

SY3TEM3 I_PP, C3VE OPERAPlLITY AND COST PICTU_P

(NAFA) ,-3 p CSCL 09C unclds

G_/33 i)27I_O6

Prepared for the

National Aerospace and Electronics Conference (NAECON)

sponsored by the Institute of Electrical and Electronics Engineers

Dayton, Ohio, May 21-25, 1990
_

_.v _L _r4
ADVANCED LAUNCH SYSTEM (ALS): ELECTRICAL ACTUATION AND POWER SYSTEMS

IMPROVE OPERABILITY AND COST PICTURE

Gale R. Sundberg

National Aeronautlcs and Space Administration

Lewis Research Center

Cleveland, Ohlo 44135

CO

Abstract

To obtain the Advanced Launch System (ALS)

primary goals of reduced costs ($300/Ib earth to

LEO) and improved operability, there must be slgnificant reductions _n the launch operations and

servlclng requirements relative to current vehicle

designs and practices. One of the primary methods

For achleving these goals is by using electrical

actuation integrated with a single vehlcle electrical power system and controls For all actuation

and avionics re_qulrements.

This paper wIYl glve a brief status review of

the ALS and _ts associated Advanced Development

Program_,to demonstrate maturation of those technologies tl_'atwill help meet the overall operablllty

and cost goals. The electric power and actuation

syStems_wlll be highlighted as a specific technology ready not only to meet the stringent ALS goals

(cryogenic Fuel valves and thrust vector controls

with peak power demands to 75 hp), but also those

of other launch vehicles, military and civilian

aircraft, lunar/Martlan vehlcles and a multitude of

commercial applications.

Introductlon L

To obtaln the Advanced Launch System (ALS)

prlmary goals of reduced _osts ($3OO/Ib earth to

LEO) and improved operability, there must be signlflcant reductions in the launch operations and

servlclng requirements relative to current vehicle

designs and practices. One of the primary methods

for achieving these goals Is by uslng electrical

actuation integrated with a single vehicle electrical power system and controls for all actuation and

avionics requirements.

Electrical actuation will eliminate a major

and persistent problem with llquld engine valves,

hydraulics and plumbing causing propulsion failures

and delays such that launch reliability has plateaued In the 0.92 to 0.96 range. It will also

significantly reduce the energy, peak power requirements and we_,ght, while raising system efficiencles

from 2 percent to well over 80 percent when compared to centralized hydraulics.

The greatest benefits, however, accrue due to

savings In prelaunch testing time permitted by the

el!mlnatlon of hydraulics and plumbing, and the SUbstit_tion of electrical actuation and an Integrated

electrical power system. The magnitude of these

-avings could exceed lO percent of the total vehlcle oDeratlons costs according to a study by the

General DynamIc, Sorporatlon showing a 5400 manhour _avlngs for their Atlas/Centaur (A/C) launch

venlc_e and a 16 000 manhour savings for the Space

Snu_.,. _ased on a Boeing Aerospace study of operat!O_S .'. Sape Kenned}'. Figure l illustrates these

oo-ent'.a} cost savings for electrical actuatlon

systems,

In the case of the Space Shuttle a prellmlnary

Assured Shuttle Availabillty study has shown a

reduced turn-around time at KSC using electric

actuators, such that at least one addltional Shuttle flight per year may be possible. In addltlon,

a welght savlngs of 2300 kg could either increase

the payload or engine margins.

Recent advances In power control and dlstribution systems and newly demonstrated capabilities

for high torque/speed control of a larger class of

Inherently rugged, Inductlon motors uslng pulsepopulation-modulatlon wlth fleld-orlented control

from a high frequency resonant llnk make the all

electric approach even more attractive. For

example, selective steering of high frequency,

small energy pulses and switching at zero crossing

significantly reduces the size and weight of the

electronics while practically ellmlnatlng EMI/EMC

effects. In addltlon, uslng embedded microprocessors and smart components with mlcrochlp BITE For

remote Identlficatlon/self-checklng will enable

dlstrlbuted system intelligence and fault tolerance

in both of the power and the avionics systems wlthout massive software Investments.

This paper w111 give a brlef status review of

the ALS program and its assoclated Advanced Development Program to demonstrate maturation of those

technologies that w111 help meet the overall operability and cost goals. Figure 2 shows the primary

subsystems that make up a typical electromechanlcal

actuator for thrust vector control of a launch

vehicle. The electric power and actuation systems

will be highlighted as a specific technology ready

not only to meet the stringent ALS goals (cryogenic

fuel valves and thrust vector controls with peak

power demands to ?5 hp), but also those of other

launch vehicles, particularly evolutionary Space

Shuttle, Assured Crew Return Vehicle, military and

c1v111an aircraft, Iunar/Martian vehicles and a

multitude of commerclal applicatlons.

Major Objectives

The scope of the ALS Advanced Development Program tasks is to develop, demonstrate and transfer

(to vehicle/equlpment manufacturers) the technology

for electromechanlcal actuators (EMA) and/or contained electro-hydraulic actuators (EHA) integrated

with a single vehicle electrical power system and

controls. Both EMAs and EHAs are electrically

driven by motors and will be referred to as electric actuators.

Reduce KSC Turn-Around Costs and Standdown Time:

Increase Launch Rate: Decrease Weight

_or any launch system the key objective is to

reduce the turn-around time and costs at KSC and,

thereby, Increase the launch rate, _mprove :he dispatch reliability and enable launchs even from a

last second hold. Use of electric actuators will
e3imlnateexcessive manpower intensive testlng and

quallf_catlon procedures. Eliminatlng centralized

hydrau!Ics will elimlnate ground support carts and

associated equipment and the problems of fluid contamlnatlon and hydraulic silting. At the present

time a study team at KSC composed of Flight Controls personnel and Lockheed are reviewing NSTS

logbooks to assess turn-around flow and subsystem

processing costs due to the hydraulic systems.

They are establishlng an analysis network of critical paths to provide quantitative trades of severa|

Items that Impact Shuttle operatlons and the number

of launches per year.

Improve Redundance, Reliability, Dispatch Reliabil-

!ty, and Safety

Electric actuation is a demand driven system

providing high peak power and torque, but It uses

small amounts of total energy. Therefore, APUs and

their associated hazardous fuels may be eliminated

and replaced by batteries, fuel cells or an electric APU. In addition electric actuators require

low amounts of standby power and energy. Electrlc

motor driven actuators are easy to implement and to

integrate automated, remote, self check-out through

mlcrochlp built-ln-test (BITE). Smart BITE microchips designed In, bullt-ln at manufacture and

easlly monitored by technicians and controllers

provide a path to vehicle health monitoring with a

minimum of software.

Si_nlficant Research Activltles

There are six candldate Government supported

programs that are working on relevant technologies

or could have slgniflcant applications for electric

actuators and an Integrated power distribution and

control system. The programs are listed below wlth

a brief explanation and noteworthy technology.

Advanced Launch System

Four Advanced Development Tasks are directed

to the development and demonstration of electrical

actuators and electrical power systems for the proposed new famlly of heavy lift launch vehlcles.

Actuators for thrust vector control (TVC), fuel

valves and others with ratings In the ranges of 5,

25, 40, and 75 hp are belng developed and subsystem

qemonstrations before March 1992. Figure 3 shows

the ALS EMA system demonstration activities and

milestones. Inspection of Table I shows that these

actuator values fit easily within the actuation

reauirements for all launch vehicles con_nonly used

by the Unlted States today including the Space

Shuttle.

The primary development work on three of the

tasks is belng done by two of the ALS vehicle prime

contractors - General Dynamics Space Systems and

Boeing Aerospace Company - and one of the engine

contractors - AeroJet General. The fourth task Is

_elng conducted by Lewis to provide advanced _K)tor

orive :ecnnology, motor designs, BITE concepts and

veb_c:e/actuator requirements and transfer the

tecnnologies _irectly to all the primes. The 5 hp

Or_ve has bee_ cemonstrated, the 25 hp drive and

actuator w_l} De :estea in March IggO, and the 30

an_ 40 _P actuators will be ready by early 1991.

The-power semiconductors necessary to meet

the peak horsepower ratings are now available and

improve_ MOSFET Controlled Thyristors (MCT) will be

ava!lable in 6 months. Circuit topologies and system archltectures are avallable, whlch meet required

redundancy, fault tolerance and fault contalnment.

An appropriate power control and distribution system Integrated wlth an avionic and propulslon system will demonstrated in 1992.

Space Shuttle Evolutlon/Shuttle "C"

JSC has supported several electric actuation

and power source studies over several years. A

prellmlnary Assured Shuttle Avallab111ty study by

Rockwell Downey concluded that electrlc actuation

was feasible, the technology was ready and a 5 to

6 year schedule was reasonable to accomplish the

DDT&E required to retroflt electric actuators Into

the existing Shuttle Orbiters. JSC is also supporting an analysis of I0 Shuttle subsystem processlng costs and turn-around flows. The EMA

system is planned as the vanguard item to trade

against the existing hydraulic systems. Shuttle

"C" is a cargo version of the Space Shuttle, which

wlll benefit significantly by application of electrical actuation systems.

Civil Transport: Power-by-Wlre/Fly-by-Light

This program Is a planned new initiative for

FYgl/92. The power-by-wire (PBW) portion of the

program includes an all electric secondary electrical power system that Includes electrical actuators, embedded engine generators, fixed bleed

turbine engines, advanced power distribution architectures, BITE and electric driven envlronmental

control systems. Studies at Lewis on a Boeing 767

class aircraft have shown a potential weight and

fuel savings of nearly lO percent by uslng the PBW

approach. Plans In this Initlatlve include development, fabrication, testing and fllght evaluation

of engineering prototypes by lg96.

Lunar/Mars Inltlatlve

Preliminary assessments have been made by the

agency for a report to the Space Council. Several

scenarios, however, require relatlvely high power

distribution systems and Include surface rovers and

minlng vehicles that will require reliable, power

efficient actuatlon and variable speed motor drive

systems.

AFIWRDC - More Electric Airplane - Retrofit of F-16

Wright Research and Development Center under

thelr More Electric Airplane Program has contracted

General Dynamics of Fort Worth, TX to do a trade

study of the F-16 resulting In development COSTS,

risks, and payoffs expected by replacing hydraulics

with electrical actuatlon systems. Performance,

operablllty, malntainabillty and recurring cost

reductlons are the main drivers.

David Taylor Ship R&D Center - Electric Navy

The US Navy has begun a massive joint program

wlth DARPA to develop technologies that will enable

all electric variable speed dr_ves of both the main

propulsion engines and new weapon systems. This will

require megawatts of power generation and dlscribution capability wlth new types of electronic control and motor drives. They plan to demonstrate a

200 hp drive by the end of 19gl and work toward a

capability to drlve 3600 hp Induction motors.

Motor drives and the required very hlgh power MCTs

and associated electronic components are already

under Intenslve development and planned qualification. New programs include development of electric

actuators to replace many hydraulic actuation

systems.
Commercial Technoloqy Transfer

Several applications are being explored through

the NASA Lewis Research Center Technology Utilization Office to apply the advanced electrical dlstributlon system and actuation systems within the

commercial sector. The capability to drive Induction motors at varlable speed with Independent control of torque, speed and dlrectlon opens up a vast

opportunity. Nearly 70 percent of all electrical

power consumed in the US drives Induction motors.

The capability to control these motors more efflciently and In servo appIIcatlons could revolutlonIze many Industrlal motor applications. In addition

many companies are Investlgatlng Innovative electrical applications to automobiles, other vehicles,

appllances and many other products.

Summar_

Electrical actuatlon, advanced electrical

power and avionics systems are ready today for

fllght vaIIdatlons. Figure 4 Is a summary of the

General Dynamics Space Systems assessment of technology readiness of electric actuation for ALS and

the National Space Transportation System (NSTS).

System requirements, speclflc DDT&E and resources,

however, are needed to bring the technology to

maturlty In a particular system applIcatlon.

Adoption of Total Quality Management (TQM)

practices on other systems besides ALS could cause

a revolution In achleving reduced operatlons costs

and Improved operablllty of systems such as the

NSTS. To Incorporate TQM, however, will require

some slgnlficant cultural changes that bring several NASA organizational codes to work together In

such a manner that candidate technologies from the

R&D sectors can be focussed and brought to maturity

in the appropriate environment. In this regard NASA

is planning a technology bridging program In which

one of the pilot initiatlves will be to mature

electrlcal actuators/power systems for advanced

space vehicle applications.

TABLE I. - ALS FAMILY OF ELECTRIC ACTUATORS MEET STS NEEDS

Stall load, lb

Dynamic load, Ib

(at actuatlon Fate)

Actuatlon rate,

deg/sec

Fluid pressure, pslg

Flow rate, Ib/sec

Response tlme, sec

-close

Actuation power, hp

Engine

prevalve

(b)

(b)

(b)

300

1250

1-2

2.1

Titan Ill

stage Ia

29 790

11 330

10

(b)

(b)

(b)

4.3

Atlas

booster

t0 750

7 510

(b)

(b)

(b)

EMA

25 hp

29 630

19 700

15

(b)

(b)

(b)

25

Titan IV STS

SRM flt

upgrade a cont.

73 940

28 692

10

(b)

(b)

(b)

32 40

SRB ALS

prel.

96 840 90 750

...... 60 3BO

10 15

(b) (b)

(b) (b>

(b) (b)

68 75

a"Appllcable TVC for ALS and MOOG Posltlon Statement," MOOG Inc., Missle System Dlvlslon, East Aurora,

New York 14052.

bparameter not applicable.

STS

74 400

4B 000

20

(b)

(b)

(b)

100
/

LAUNCHOPERATIONSCOSTS

AVIONICS AND_FLUIDS,

STRUCTURES PIECtlANICAL,

AND PROPULSION

QUALITY

(QA) AND

REWORK

:ACILITIES AND

MANAGEMENT

FLUIDS, MECHANICAL AND PROPULSION

PROPULSION

TEST COSTS

RCS

'LUIDS HYDRAULICS

PNEUMATICS

TOTAL A/C LAUNCH OPERATIONS 91 575 HR$

% SAVINGS

TOTAL ]F/MP TEST TIME 19 197 HRS IF EMAs USED

FLUIDS q929 HR 10%

HYDRAULICS 2177 HR 90_{

PNEUMATICS 5143 HR 40%

PROPULSION 4616 HR 20%

RCS 2333 HR >_'J_

TOTAL STS LAUNCH OPS

EQUIVALENT SHUTTLE HOURS

326 444 HR

SAV INGS

qgo

1960

2060

920

0

PLUMBING, VENT,

AND DRAIN 2880 HR 20% _6

HYDRAULICS 4236 HR 90% 3812

PROPULSION 27 200 HR lOg 2720

ACS 565q HR >B% 0

VAB ACTIVITIES

PAD OPERATIONS (35%)

USE OF ELECTROMECHANICAL VALVES AND ACTUATORS CAN REDUCE A/C TEST

TIME BY >SO00 HR, AND POTENTIALLY >16 000 HR FOR THE SHUTTLE

FIGURE I. - POTENTIAL SAVINGS FROM ELECTRIC ACTUATORS.

5670

3600

CONTROLLER/ F ELECTRIC CABLE

INVERTER UNIT I • POWER

I " C_ND ELECTRIC

, •EEED CK .OTOR

SCREW

( /___ __llv "-- BALL SCREWNUT

_WER SOURCE

(BATTERY)

FIGURE 2, - TYPICAL MAJOR EMA SUBSYSTEMS.

4
TECHNOLOGY/'_TURITY

EMA ADP PART ]I --- GDSS "_ INTEGRATED APPROACIIFOR

NASA LEWIS TASK ORDER / TECHNOLOGY DEVELOPMENT 75 HP

hO HP

EMA SYSTEM TECHNOLOGY

FOR ALS APPLICATION

COMPLETE CLOSED LOOP DEMO

STS I'VCAPPLICATION

I 5 HP J -

20 KHZ, 10 Kw

INVERTOR, CONTROLLER

MOTOR TECHNOLOGY

- 2ND GENERATION MOTOR

CONTROLLER TECHNOLOGY

ADVANCED CONCEPTS

25 HP STS FLIGHT CONTROL APPLICATION

20 KHZ, 25 Kw

INVERTOR, CONTROLLER

TECHNOLOGY

STS FLIGHT CONTROL APPLICATION

J = COMPLETED

MARCH '90 APRIL "91 MARCH '92

SYSTEM DEMONSTRATION MILESTONES

FIGURE 3. - ALS TOTAL SYSTEM APPROACH FOR ELECTRIC ACTUATORS.

SUMMARY

• PRELIMINARY EMA TRADES ARE COMPLETE

• ALS REFERENCE VEHICLE

• SHUTTLE ORBITER CLASS VEHICLES

• HARDWARE DESIGNS ARE NOW IN WORK

• ORDERLY PROGRESSION TO FULL POWER

• ALL THE BASIC REQUIRED TECHNOLOGIES ARE AVAILABLE

• POWER PROCESSING TECHNOLOGY AND COMPONENTS

• AC MOTORS

• COMPUTER CONTROLS AND MOTOR CONTROL ALGORITHMS

• MECHANICAL COMPONENTS

FIGURE 4. - GENERAL DYNAMICS ASSESSMENT OF TECHNOLOGY READINESS FOR

ELECTRIC ACTUATORS.
National Aeronautics and

Space Administration

1. Report No.

NASA TM-102547

4. Title and Subtitle

Advanced Launch System (ALS): Electrical Actuation and

Power Systems Improve Operability and Cost Picture

7. Author(s)

Gale R. Sundberg

9. Performing Organization Name and Address

National Aeronautics and Space Administration

Lewis Research Center

Cleveland, Ohio 44135-3191

12. Sponsoring Agency Name and Address

National Aeronautics and Space Administration

Washington, D.C. 20546-0001

Report Documentation Page

2. Government Accession No. 3. Recipient's Catalog No.

• 5. Report Date

6. Performing Organization Code

8. Performing Organization Report No.

E-5358

10. Work Unit No.

549-03-1A

11. Contract or Grant No.

13. Type of Report and Period Covered

Technical Memorandum

14. Sponsoring Agency Code

15. Supplementary Notes

Prepared for the National Aerospace and Electronics Conference (NAECON) sponsored by the Institute of

Electrical and Electronics Engineers, Dayton, Ohio, May 21-25, 1990.

16. Abstract

To obtain the Advanced Launch System (ALS) primary goals of reduced costs ($300/1b earth to LEO) and

improved operability, there must be significant reductions in the launch operations and servicing requirements

relative to current vehicle designs and practices. One of the primary methods for achieving these goals is by

using electrical actuation integrated with a single vehicle electrical power system and controls for all actuation

and avionics requirements. This paper will give a brief status review of the ALS and its associated Advanced

Development Program to demonstrate maturation of those technologies that will help meet the overall operability

and cost goals. The electric power and actuation systems will be highlighted as a specific technology ready not

only to meet the stringent ALS goals (cryogenic fuel valves and thrust vector controls with peak power demands

to 75 hp), but also those of other launch vehicles, military and civilian aircraft, lunar/Martian vehicles and a

multitude of commercial applications.

18. Distribution Statement

Unclassified - Unlimited

Subject Category 33

17. Key Words (Suggested by Author(s))

Electrical actuators; Electrical power systems;

Electromechanical; Electrohydraulic; Conditioning;

Control; Distribution; Launch vehicles; Space

transportation

19. Security Classif. (of this report) 20. Security Classif. (of this page) 21. No. of pages

Unclassified Unclassified 6

NASAFORMle2eOCT86 *For sate by the National Technical Information Service. Springfield, Virginia 22161

22. Price*

A02