During the Electric Propulsion Space Experiment (ESEX) mission, eight firings of the 26 kW ammonia arcjet were performed. Data taken from on-board systems, GPS and ground tracking during these firings are used to determine thruster performance. The on-board Servo Accelerometer Assembly (SAA) measured spacecraft acceleration. The mean values of thrust, specific impulse and thrust efficiency are 1.93 +/- 0.06 Newtons, 786.2 +/- 43.0 seconds and 0.267 +/- 0. 021, respectively. This measured performance is lower than expected based on ground test. The most likely cause of this discrepancy is onboard measurement error in discharge power due to a 6% drift in the power processing unit current shunt. At the corrected power, performance falls within the expected envelope.
Refined Orbital Performance Measurements of the Air Force Electric Propulsion Space Experiment (ESEX) Ammonia Arcjet
2001
26 pages
Report
No indication
English
Electric & Ion Propulsion , Astronautics , Electric propulsion , Space propulsion , Test and evaluation , Orbits , Experimental data , Spacecraft , Accelerometers , Tracking , Ammonia , Global positioning system , Onboard , Thrusters , Servomechanisms , Specific impulse , Electrojets , Silver zinc batteries , Esex(Electric propulsion space experiment) , Ammonia arcjet , Saa(Servo accelerometer assembly) , Pfs(Propellant feed system) , Power subsystem , Power conditioning unit