Applied resistojet technology

Abstract

A b s t r a c t The s y s t e m used is d e s c r i b e d in R e f . 5. The f i r s t generation resistojets w e r e develope d eight years a g o to o p e r a t e at 1 to 20 kilowatts. Following recognition that power levels of kilowatts would .lot be available o n unmanned s p a c e c r a f t f o r s o m e t i m e , development commenced o n the lower power r e s i s t o j e t s which r e s u l t e d in flight applications. With acceptance of the r e s i s t o j e t as a n ope r a t i o n a l s u b s y s t e m , specific unmanned s p a c e c r a f t applications have g e n e r a t e d new r e s i s t o j e t design c r i t e r i a . performance modeling and definitions should be established f o r communication and c o m p a r i s o n of t h r u s t e r p e r f o r m a n c e d a t a . moclclcd t h r u s t e r s using ammonia propellant i s rep o r t e d . R t s i s t o j e t d e s i g n s m u s t be capable of P e r f o r m a n c e of two Studies of i m p u l s e r e q u i r e m e n t s and availability of biowaste propellants o n manned s p a c e stations -space b a s e s have given impetus to evaluation of r e s i s t o j e t p e r f o r m a n c e with typical biowaste p r op e l l a n t s . initial p e r f o r m a n c e data of m e t h a n e , c a rbon dioxide and w a t e r a r e p r e s e n t e d . The two general types of low power r e s i s t o j e t s Schematic diadeveloped f o r these flight applications a r e "thermal-s t o r a g e " andYast heat-up.g r a m s of t h e s e two b a s i c t h r u s t e r types a r e shown i n F i g u r e 1. has used a r e f r a c t o r y , high heat capacity heater e l e m e n t . Power is continuously applied to this e l e m e n t a n d the propellant flow is pulsed. The h e a t e r a n d t h r u s t e r insulations a r e desizned so that a given pulse of mass flow will have the d esired a v e r a g e specific impulse. this type of t h r u s t e r f o r pulsed flow requirements is lower p e a k powers f o r high specific impulses. The disadxantage is that the flow must be pulsed at a r a t e d e t e r m i n e d by the amount of power available, the desired t h r u s t l e v e l and specific impulse.The t h e r m a l -s t o r a g e engine in g e n e r a l

Performance characterizations of an engineering model multipropellant resistojet

“…One could envision two systems: the first of these employs a separate water vaporizer upstream of the thruster, with the thruster serving only to superheat the steam 5 ; the second would combine the vaporizing and superheating functions into a single unit. 8 Since the engineering model thruster originally was envisioned to operate on steam in combination with a separate steam generator, it was never optimized to perform as a water vaporizer. However, it was decided during the performance testing program to make minor modifications to the engineering model to facilitate operation as a liquid water-fed thruster.…”