GNC FOR MARCO POLO-R AND MOONS OF MARS SAMPLE RETURN MISSIONS: SYSTEM DESIGN, CRITICAL TECHNOLOGIES AND SYNERGY

The European Space Agency (ESA) roadmap towards exploration of small solar system bodies includes the Rosetta mission, currently on its way to a comet and two asteroid sample return mission studies: Marco Polo-R (MP-R) and Moons of Mars Sample Return (MMSR), also known as Phootprint. This paper focuses on MP-R and MMSR. MP-R is being studied in the frame of the Cosmic Vision ESA Science Programme whereas MMSR is studied in the frame of the Mars Robotic Exploration Programme. Several critical technologies are similar between these two mission concepts and in particular the Guidance, Navigation and Control (GNC) aspects including the guidance strategy, the use of relative vision-based navigation, and the proximity and landing operations. This paper discusses the overall design constraints; architecture and performances assessment achieved by the GNC subsystem for both of these sample return mission concepts. ESA initiated both study activities in the Concurrent Design Facility (CDF) followed by parallel system assessment studies, led by two industrial teams as well as set of technology-focused activities bringing about the various critical elements to the appropriate maturity level. Sample return missions are demanding from a GNC perspective. The most critical phase deals with the proximity operations around the small body and more particularly, with the descent and landing (D&L) phase during which the samples to be returned to the Earth are collected. The actual landing accuracy requirement for these two ESA missions is aimed to be in the order of tens or hundreds of meters, depending on the small body size, using visual based techniques as main D&L navigation aid.