2000-hour cyclic endurance test of a laboratory model multipropellant resistojet

Abstract

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 .

Preliminary performance characterizations of an engineering model multipropellant resistojet for space station application

“…The component parts of the heat exchanger were fabricated and assembled by Johnson-Matthey, and contained a small quantity (less than 1 percent) of zirconium oxide dispersant as a grain stabilizer to minimize grain growth which occurs when materials are held at high temperatures for extended periods of time (ref. 8). Excessive grain growth leads to distortion and weakening of components, which is of special concern for the pressure vessel/heat exchanger of a resistojet.…”