SUMMARYlhis paper presents the results of a program to describe the operational characteristics of an engineering model multipropellant resistojet for application as an auxiliary propulsion system for space station. Performance was measured on hydrogen, helium, methane, water (steam), nitrogen, air, argon, and carbon dioxide. Thrust levels ranged from 109 to 355 mN, power levels ranged 2 from 167 to 506 W , and specific impulse values ranged from 93 to 385 sec, depending upon the propellant, chamber pressure, and heater current level cr: selected.obtained for operation with carbon dioxide. Detailed thermal maps of the heater and heat exchanger were alsoINTRODUCl ION lhis paper presents the results of a test program designed to describe the operating characteristics of an engineering model multipropellant resistojet. lhe multipropellant resistojet has been baselined as the low-thrust option for the space station propulsion system. The resistojet can provide low levels of thrust for drag make-up while disposing of a variety of fluids expected t o be present in excess quantities on board space station. The use of such fluids as propellants will result in significant reductions in Space Transportation System costs which would be associated with launching of the necessary propellants as well as the removal of waste fluids from space station. Recent studies have explored these and other potential benefits of a propulsion system incorporating low-thrust resistojets (refs. 1 and 2). goals emphasize thruster life, reliability, and multipropellant capability rather than optimum performance. The design life goal is a minimum of 10 000 hr for thrusters operating on hydrogen, helium, methane, water (steam), nitrogen, air, argon, and carbon dioxide at specific impulse and thrust levels of 100 to 500/sec and 130 to 450 mN, respectively.The main objective of this program was to evaluate the operating characteristics of an engineering model multipropellant resistojet which was designed and fabricated by the Rocketdyne Division of Rockwell International and Technion Incorporated as part of the Space Station Advanced Development Program. The engineering model thruster incorporates design features which enable it to operate on a wide variety o f fluids for extended periods of time. This thruster was characterized on the above mentioned fluids. Performance data were obtained for each propellant (except steam) at two thrust levels for each of two input electric power levels. Data were obtained for steam operation at a variety of power levels for each of two conditions: steam supplied to the thruster from a water vaporizer and liquid fed directly to the thruster. Detailed informatlon about the temperature distribution within the heater and heat exchanger was also obtained for operation with carbon dioxide. The thermal transient behavior of the engineering model was investigated for operation with carbon dioxide and argon. The information gained from these tests served as input to a design iteration intended to enhance the operational ...

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This paper presents the results of an effort by the NASA Lewis Research Center (LeRC) to demonstrate the technology readiness of a long-life multipropellant resistojet for Space Station auxiliary propulsion.

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SUMMARYThis paper presents some r e s u l t s o f an e f f o r t t o demonstrate t h e technol o g i c a l readiness o f a l o n g -l i f e m u l t i p r o p e l l a n t r e s i s t o j e t f o r Space S t a t i o n a u x i l i a r y propulsion. A l a b o r a t o r y model r e s i s t o j e t made from g r a i n -s t a b i l i z e d p l a t i n u m served as a t e s t bed t o evaluate t h e design c h a r a c t e r i s t i c s , f a b r i c at i o n methods, and operating s t r a t e g i e s f o r an engineering model m u l t i p r o p e l l a n t r e s i s t o j e t developed under c o n t r a c t by t h e Rocketdyne D i v i s i o n o f Rockwell I n t e r n a t i o n a l and Technion Incorporated. The l a b o r a t o r y model t h r u s t e r was subjected t o a 2000-hr, 2400-thermal-cycle endurance t e s t u s i n g carbon d i o x i d e w p r o p e l l a n t . Maximum t h r u s t e r temperatures were approximately 1400 O C . The p o s t -t e s t analyses o f t h e l a b o r a t o r y model t h r u s t e r included an i n v e s t i g a t i o n o f component m i c r o s t r u c t u r e s . S i g n i f i c a n t observations from t h e l a b o r a t o r y model t h r u s t e r a r e discussed as t h e y r e l a t e t o t h e design o f t h e engineering model t h r u s t e r .