HOLEY SOLAR SYSTEM! CAVE AND KARST FEATURES ON OTHER PLANETARY BODIES AND PROSPECTS FOR DETECTION AND CHARACTERIZATION (Invited Presentation)

Interest in possible caves or karst terrain on other bodies in the Solar System has grown over the past decade or two spurred on by detection of apparent volcanic caves on the Moon, Mars, Io, Venus, and Mercury seemingly produced by processes resembling those on Earth. Additionally, extremely cold icy bodies like Titan, Europa, or Enceladus may exhibit cavity-forming processes that we see in Earth’s polar regions. There may also be other unique speleogenetic mechanisms that truly stretch our imagination e.g. cavities produced by sublimation of comets upon perihelion passage or karst-like processes on minor planets or large asteroids which recent space missions appear to show are more geologically evolved than previously thought. Can a body like Pluto produce karst-like terrain? Before the recent New Horizons mission that explored that body, no one would have ever asked such a question!

The desire to access caves stems from a variety of reasons: 1) the enhanced view of the geological processes at work provided by a perspective that goes beyond surficial outcrops, 2) materials that cavities contain may be in a different state of preservation than materials on the surface, particularly where high energy radiation impinges on surfaces altering them or active weathering are occurring on bodies with atmospheres, 3) and on planetary targets deemed to have astrobiological potential (e.g. Mars, Europa, and Enceladus), subsurface cavities could provide habitat with significantly different properties than surfaces, or provide circumstances where past life traces are protected from surficial challenges. Discovery of dissolutional karst-like processes under radically non-Earthlike conditions (e.g. Titan) provide a challenging way to test our understanding of Earthly karst processes.

Detection, exploration, and study of such cave and karst features will rely on orbital and landed missions to visit those bodies in the future. Emerging techniques including muon imaging, improved resolution ground-penetrating radar, high-resolution multispectral imaging, and other techniques will be necessary to detect and characterize such features. Novel robotic mobility, refined entry-descent-&-landing (EDL) schemes, and developments in autonomy and communications are required to provide access to planetary subsurface terrain.