Saturn IB/Centaur and Atlas/Centaur launched electric propulsion vehicles ... It is true that Saturn V boosters with additional high-energy chemical upper.
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NASA TM X- 52201
TECHNICAL MEMORANDUM
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SOlARfLECTRIC PROPULSION SYSTEM PERFORMANCE FOR THE 0. I-AU SOLAR PROBE MISSION
GPO PRICE
$
CFSTI PRICE(S) $
by William C. Strack Lewis Research Center
Hard copy (HC)
Cleveland, Ohio
Microfiche (MF) July65
*
i
TECHNICAL PAPER proposed for presentation at ‘Vest Coast Aerospace Sciences Meeting sponsored by the American Institute of Aeronautics and Astronautics Los Angeles, California, June 27- 29, 1966
2. b-0 #&*
SOLAR-ELECTRIC PROPULSION SYSTEM PERFORMANCE FOR THE 0.1-AU SOLAR PROBE MISSION by William C. Strack
Lewis Research Center Cleveland, Ohio
TECHNICAL PAPER proposed for presentation at West Coast Aerospace Sciences Meeting sponsored by the American Institute of Aeronautics and Astronautics Los Angeles, California, June 27-29, 1966 NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
SOLAR-EIXTRIC PROPULSION SYSTEN PERFORMANCE
FGR TIlE 0 . l - A U S O U ? ,%GEE by William C.
.MISSION
Strack*
L e w i s Research Center National Aeronautics and Space Administration Cleveland, O h i o
ABSTRACT Saturn IB/Centaur and Atlas/Centaur launched e l e c t r i c propulsion vehicles employing present o r near-f'uture state-of-the-art power supplies (50 t o 100 lb/kWe) a r e shown t o be a t t r a c t i v e systems f o r performing t h e 0.1-AU s o l a r
probe mission.
This r e s u l t compares favorably with t h e a l t e r n a t i v e systems
composed of t h e same boosters b u t w i t h chemical o r nuclear f i n a l stages a r e inadequate f o r t h i s mission.
-
which
The performance calculations f o r t h e e l e c t r i c
propulsion systems include t h e optimization of t h e launch vehicle burnout velocity, t h e e l e c t r i c stage s p e c i f i c impulse and power l e v e l , and t h e t h r u s t o r i e n t a t i o n f o r constant s p e c i f i c impulse t h r u s t o r s . presented.
Two s e t s of r e s u l t s a r e
The f i r s t s e t i s associated with constant power operation of t h e
t h r u s t o r s as would be t h e case f o r nonsolar dependent power supplies such a s nuclear-electric systems.
The second s e t of d a t a represents solar- c e l l -
powered e l e c t r i c systems.
I n t h i s case t h e t h r u s t o r power i s a function of
t h e sun-vehicle distance.
flow rate.
The power i s varied by adjustment of t h e propellant
O f s p e c i a l i n t e r e s t i s the fact t h a t absolute optimal t r a j e c t o r i e s
f o r t h e s o l a r c e l l systems belong t o an e n t i r e l y d i f f e r e n t c l a s s than those optimals associated with constant power systems.
*Aerospace Research Engineer
2 4 X-52201
NOMENCLATURE 80
i n i t i a l acceleration of e l e c t r i c stage, ft/sec2
z( %)
pover p r o f i l e einctioo
go
32.174 f't/sec2
I C
s p e c i f i c impulse of chemical stage, sec
Ie
s p e c i f i c impulse of e l e c t r i c stage, sec
K
hardware f r a c t i o n of chemical stage
k
r a t i o of tankage t o propellant mass of e l e c t r i c stage hardware mass'(propel1ant tanks, engines, structure, etc. ) of chemical stage, l b
i n i t i a l mass of vehicle i n c i r c u l a r Earth o r b i t , lb propellant mass of chemical stage, 1% f i n a l mass, l b payload mass, lb i n i t i a l mass of e l e c t r i c stage, l b propellant mass of e l e c t r i c stage, lb powerplant mass of e l e c t r i c stage, lb s t r u c t u r e mass of e l e c t r i c stage, lb tankage mass of e l e c t r i c stage, lb t o t a l power delivered t o e l e c t r i c t h r u s t o r s , kW
r
h e l i o c e n t r i c radius, AU i n i t i a l c i r c u l a r Earth-orbit radius, f t radius of sphere of influence, f t chemical stage burnout velocity, f t / s e c c i r c u l a r Earth-orbit velocity, f t / s e c 2
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