SEP for a lander mission to the jovian moon europa
- Paper number
IAC-06-C4.4.04
- Author
Dr. Horst W. Loeb, University of Giessen, Germany
- Coauthor
Dr. Karl-Heinz Schartner, Giessen University, Germany
- Coauthor
Dr. Wolfgang Seboldt, German Aerospace Center (DLR), Germany
- Coauthor
Mr. Joern Streppel, Deutsches Zentrum fur Luft und Raumfahrt e.V. (DLR), Germany
- Coauthor
Dr. Bernd Dachwald, German Aerospace Center (DLR), Germany
- Year
2006
- Abstract
Under DLR-contract, Giessen University and DLR Cologne are studying missions to the outer regions of the solar system with solar electric propulsion (SEP). One of the reference missions deals with the deposition of a surface module on Europa, which is of high scientific interest. The challenges of the Europa mission (high Δv-requirement, strongly decreasing solar constant, and very high radiation doses in Jupiter’s neighbourhood) may be met by introducing the stage principle into EP. Two model spacecrafts with BOM-masses of 2.65 tons and 4.45 tons, respectively, show the following scenario: Launched to escape velocity (with C 3 = 0), a 41 kW or 75 kW solar array equipped with concentrators (12 kg/kW in total) will feed the first EP stage which is equipped with a cluster of 5 or 7 ion thrusters, respectively. To save propellant mass, high specific impulse engines (with I sp = 5700 s to 6500 s) should be used. In about 3.75 AU of Sun distance, the burnt-out stage (355 kg or 575 kg, respectively) will be jettisoned, and the second EP – stage, integrated in the spacecraft, will be ignited. Now, to save power, this stage will be propelled by 2 or 4 low specific impulse thrusters (with e.g. I sp = 3300 s). Having reached Jupiter´s sphere of influence, the SEP–spacecraft will spiral down into e.g. an orbit of 35 Jupiter radii, release there a chemically propelled probe and act furtheron as telemetry relay station. By using Callisto, Ganymed and Europa gravity assists, the probe with a mass of 350 kg (or 700 kg for the augmented version) will continue its journey toward Europa and the landing scenario might be analogue to the Mercury lander studied by the Babakin Space Center for BepiColombo. The paper describes in detail the two EP-stages with their clustering strategy and the two proposed thruster types. Refering to the high reliability of electrodeless discharges and their relatively simple control loops (which simplify the cluster control), the rf-ion thruster is well suited. The actual RIT-22 engines might be used after modification of the grid system. For beam voltages between 1 and 5 kV, the calculated geometrical dimensions of the grid systems, the thruster performance data and the estimated lifetime will be given. During the Europa-mission, all RIT-22 engines will be operated up to less than 67% of their lifetime limits, provided they are equally loaded by thrusters switching within the cluster .
- Abstract document
- Manuscript document
IAC-06-C4.4.04.pdf (🔒 authorized access only).
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