Sub-ice Autonomous Underwater Vehicle Architectures for Ocean World Exploration and Life Search

Ice-covered oceans are found across the Solar System. On Earth, such environments are known to harbor life. On some Ocean Worlds such as Europa, the unique combination of an actively recycled ice shell and rocky, possibly magmatic interior may give rise to a geochemical system suitable to life and not so terribly different from the terrestrial cryosphere, where the ice may act as a suitable interface along which melt and freeze provide chemical gradients of which life can take advantage. The entry into sub-ice oceans of Ocean Worlds calls for the development of autonomous underwater vehicle (AUV) rovers to explore these water bodies. The most fruitful places to search for life will be at energy sources provided by physical and chemical gradients, which may not necessarily occur at the break-through location of a cryobot. This implies exploration using a mobile platform, and this in turn–due to extremely limited bandwidth and hours-long round-trip transmission delay–must be an autonomous platform. This forms the final step of an Ocean Worlds life search program. An intelligent underwater robotic explorer which can travel in an icecovered ocean; identify signs of biological activity; home in on, acquire, and analyze samples; and return to a docking station (the cryobot “mothership”) to upload data and recharge is a powerful tool in the search for life off Earth.