Engineering topics
Ziemer, J.
Publications and source records attributed to Ziemer, J..
Characterization of colloid thruster beams
In this article we use retarding potential, time of flight, and a Faraday cup, to measure the energy and specific charge distributions of the electrospray particles as a function of the position within the beam, as well as beam profiles. This information is then used, together with a model of the beam, to calculate its spreading.
Electric propulsion research and development at JPL
In this paper, we will describe the electronic propulsion technologies of interest and our role in developing and interjecting these technologies into JPL missions.
Performance characterization of the Vaporizing Liquid Micro Thruster (VLM)
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Performance characterization of the Vaporizing Liquid Micro Thruster (VLM)
A Vaporizing Liquid Micro-Thruster (VLM) microfabricated thruster was tested on water propellant on a thrust stand and performance data obtained.
JPL micro-thrust propulsion activities
Formation flying and microspacecraft constellation missions pose new propulsion requirements. Formationflying spacecraft, due to the tight positioning and pointing control requirements, may need thrust control within 1- 20 uN to an accuracy of 0.1 uN for LISA and ST-7, for example. Future missions may have extended thrust ranges into the sub - mN range. However, all do require high specific impulses (>500 sec) due to long required thruster firings.
Performance of gas fed pulsed plasma thrusters using water vapor propellant
The performance of two gas-fed pulsed plasma thrusters (GFPPTs) using both argon and water vapor for propellant has been measured using the JPL microthrust stand.