The Opportunities and Challenges of Gnc on a Europa Cubesat Mission Concept

Jupiter’s moon Europa is the target of NASA’s planned Europa Mission. The mission hopes to provide the most detailed view yet of the surface and subsurface of Europa and answer some fundamental questions, including whether Europa has a liquid-water ocean beneath a thick ice shelf, and if these conditions may harbor life. It is envisioned the multiple flyby mission would be only the first in a series of missions that could culminate into a surface landing mission. NASA JPL has sought proposals for CubeSats that could be carried by the main spacecraft and which would be released during the flybys. A CubeSat could significantly complement the capabilities of the multiple-flyby spacecraft. It could perform high-risk, high-payoff science missions at low altitudes. A CubeSat could provide unique science data that could not be obtained by the mothership by doing a low-altitude flyby and impact mission. A CubeSat could also perform landing site reconnaissance in preparation for a future surface lander mission. All of these capabilities depend on advances in guidance, navigation and control for use in the Jovian system. Three factors make a CubeSat concept challenging, including the high radiation in the vicinity of Europa, the low solar insolation of 50 W/m 2 and extremely low temperatures of -230 o C. Coupled with these challenges, Europa lacks an atmosphere sufficient for aero-braking. Our concept is focused on having the CubeSat separate from the mothership, 10 hours before a close flyby of Europa lasting 20 minutes. The CubeSat would use its onboard propulsion to attain altitudes of 3 to 12 km above the moon’s surface travelling at 4-5 km/s. Using the onboard optical navigation techniques, the CubeSat would navigate along Europa’s shadowed surface fractures to obtain detailed images of nearby features at 0.3 to 2 m/pixel. The notional spacecraft has the capacity to sample for and analyze potential plume samples, and this option could be utilized to get first answers about potential plume content. The mission concept culminates with the CubeSat impacting the Europa surface. The artificial impact plume created would be analyzed by the array of instruments onboard the Europa Mission spacecraft for material composition. Advances in GNC are required to handle the unique lighting, low temperature and high velocity conditions of the mission concept. Our early feasibility work shows a development pathway towards advancing the requisite technology towards technical feasibility.