The NASA Jet Propulsion Laboratory is preparing missions to Jupiter’s icy moon Europa, which is believed to harbor an ocean of liquid water underneath its icy crust. One mission scenario involves placing a lander onto Europas surface to sample its composition. The approach involves a breaking and hovering maneuver that makes use of small hydrazine thrusters, during which the thruster plumes inevitably impinge onto the future sampling site. The aim of the EPIC project is to characterize the extent to which plume induced contamination and erosion affect representative surface materials. Two NASA-supplied hydrazine thrusters are fired in a high-vacuum environment in order to correctly reproduce the plume expansion in space. A number of material samples are exposed to the plume in the test section, and the plume’s chemical composition is analyzed with a fast in-situ mass spectrometer. Engineering models for plume induced contamination and erosion may be obtained from the experimental data obtained in the project. These can then be used to assess design concepts for orientation and operating parameters of the thrusters used during the approach to Europa, with respect to their impact on surface alteration.
The DLR-Institute of Aerodynamics and Flow Technology has been contracted by the Jet Propulsion Laboratory, as its High-Vacuum Plume Test Facility for Chemical Thrusters is the only suitable large vacuum facility capable of maintaining high vacuum even during thruster operation.