Wolfgang Seboldt, Bernd Dachwald, Jörn Streppel, Andreas Ohndorf, Horst Loeb, Karl-Heinz Schartner
Lander Mission to Europa with Solar Electric Propulsion
7th International Symposium on Launcher Technologies, 2007, Barcelona,


A robotic mission to Jupiter with the goal to place a lander on the moon Europa has been studied on behalf of DLR, using solar electric propulsion and advanced triple-junction solar arrays. The mission analysis addresses the transfer from Earth escape to Jupiter rendezvous, Jupiter capture and ‘spiral down’ to a ‘relay orbit’ - where the main spacecraft is stationed and the lander released - and finally the lander transfer to the surface of Europa. The lander is equipped with chemical propulsion and applies gravity assists at the Galilean moons, so that only a moderate ΔV is taken into account. The spacecraft design and corresponding trajectory calculations are performed parametrically. Ion engine clusters (with RIT-22) are considered and the thrusters are switched off one after the other - due to the decreasing solar power - until at Jupiter only one or a few are used. The derived most promising scenario applies a staging principle with thrusters of different specific impuls Isp, where the high Isp engine cluster is jettisoned after about half way to Jupiter and the low Isp engines enable the Jupiter rendezvous, capture and spiraling down to the final relay orbit at 80 Jupiter radii. There the chemical landing vehicle is released. The paper demonstrates that a total mission time around 5 to 6 years is achievable with a launch mass of about 5 tons (perhaps even scaled down to 2.5 tons – pending on a more detailed analysis).