Regensburg 2016 – wissenschaftliches Programm

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VA: Fachverband Vakuumphysik und Vakuumtechnik

VA 1: Large Vacuum Systems

VA 1.2: Vortrag

Montag, 7. März 2016, 09:45–10:15, H25

Vacuum solutions for ion thruster testing — •Stefan Lausberg — Oerlikon Leybold Vacuum, Bonner Str. 498, 50968 Köln, Germany

Electrical propulsion is the keyword for nowadays movement of space vehicles. Here ionized particles, usually xenon, are accelerated by thrusters in an electric field. State-of-the-art xenon thrusters emit a gas flow of 0.1 to 10 mg/sec. In order to maintain a high vacuum pressure at this flow in thruster test chambers, a large pumping speed is required, often in the range of 10'000 to 100'000 l/s for xenon. The benefit of a large mass for propulsion on the one hand is a huge challenge for vacuum pumps on the other hand. One of the reasons is the poor thermal conductivity of xenon gas which leads to critical temperature rises in gas transfer vacuum pumps like turbomolecular pumps. Moreover, dozens of large turbomolecular pumps would be necessary to reach the required pumping speed. We will show that big standard cryopumps are no appropriate solution either - even though they can principly provide large pumping speeds.

Oerlikon Leybold Vacuum has developed an optimized and simple cryogenic solution for xenon pumping. Strong single-stage Gifford-McMahon type cold heads carry metal discs which condense the xenon gas with a pumping speed at the edge of the theoretical limit. In this talk, we will present the whole vacuum system for a thruster testing facility.