Onboard Scheduling and Execution to Address Uncertainty for a Planetary Lander

The Europa Lander Mission Concept presents a number of challenges. The current mission concept would land with a fixed amount of energy, an expected mission lifetime of approximately 30 days, and would be able to communicate with the Earth in less than 42 out of every 84 hours due to the Europa-Jupiter orbit. Additionally, planned activities such as trenching and sampling, will interact significantly with a largely unknown environment and therefore may encounter failure or highly variable duration or energy consumption when executing. All of these factors present challenges for a conventional ground operations paradigm. We describe advanced prototyping of onboard autonomy software to address such challenges. Onboard event driven execution and rescheduling offer promise to enable the lander to adjust to execution feedback without incurring costly ground interaction. We describe prototyping with the TRACE execution system and the Mexec scheduling and execution system. We show how these autonomy systems can address: uncertainty in domain modeling, stochasticity at execution time, and the presence of exogenous events.