Floating potential and ion current density measurements were taken on the laboratory model NASA-173Mv2 in order to improve understanding of the physical processes affecting Hall thruster performance at high specific impulse. Floating potential was measured on discharge chamber centerline over axial positions spanning 10 mm from the anode to 100 mm downstream of the exit plane. Ion current densi...

A Faraday probe with three concentric rings was designed and fabricated to assess the effects of gap width and probe geometry in a systematic study of the Hall thruster plume. The nested Faraday probe consisted of two concentric collector rings and an outer guard ring, which enabled simultaneous current density measurements on the inner and outer collector. Two versions of the outer collector w...

The flowfield of a magnetoplasmadynamic thruster was simulated numerically and the results compared to experimental measurements, in order to validate the code and obtain insight into underlying physical processes. The thruster chosen was the full-scale benchmark thruster, because it has been the subject of many experimental studies. The parallelized axi-symmetric code featured detailed physica...

Navigation in autonomous vehicles involves integrating measurements from on–board inertial sensors and external data collected by various sensors. In this paper, the computer–frame velocity error model is augmented with a random constant model of accelerometer bias and rategyro drift for use in a Kalman filter–based fusion of a lowcost rotating inertial navigation system (INS) with external pos...

We report the use of cavity ring-down spectroscopy (CRDS) as a diagnostic tool to study sputter erosion of the VHITAL (Very High Isp Thruster with Anode Layer) thruster. The lifetime of the VHITAL thruster is largely governed by sputter erosion of guard-rings and other critical components. The CRDS technique will be used to measure sputtered molybdenum in the plume of the thruster for various t...

Two objectives dominate consideration of control moment gyroscopes for spacecraft maneuvers: high torque (equivalentlymomentum) and singularity-free operations.This paper adds to the significant bodyof research toward these two goals using a minimal three-control-moment-gyroscope array to provide significant singularity-free momentum performance increase spherically (in all directions) by modif...

We have designed and realised a micromachined micro Coriolis flow sensor for the measurement of hydrazine (N2H4, High Purity Grade) propellant flow in micro chemical propulsion systems. The sensor should be able to measure mass flow up to 6 mg/s for a single thruster or up to 24 mg/s for four thrusters. The sensor will first be used for measurement and characterisation of the micro thruster sys...

A novel multi-mode spacecraft propulsion concept is presented. The concept combines chemical monopropellant and electric pulsed inductive thruster technology to include shared propellant and shared conical nozzle. Geometry calculations show that existing conical pulsed inductive thruster experiments are typical of large (1000-4000 N) chemical monopropellant thruster nozzles. Performance and pro...

The charge-exchange xenon (CEX) ion generated by ion thruster can backflow to the surface of spacecraft and threaten to the safety of spacecraft operation. In order to evaluate the effects of the induced plasma environment in backflow regions on the spacecraft, we designed a spherical single Langmuir probe of 5.8cm in diameter for measuring low-density plasma parameters in backflow region of io...

Presented are preliminary measurements of near-cathode ion velocity distributions using time-resolved laser induced fluorescence. Two experiments were performed. First, time-averaged velocity distributions were measured in a LaB6 hollow cathode plume under the influence of a Hall thruster magnetic field provided by the 6-kW H6 thruster. The discharge was sustained without a downstream anode but...