DOWN-SELECTING PUTATIVE MARTIAN CAVES AS VIABLE TARGETS FOR FUTURE IN-SITU EXPLORATION (Invited Presentation)

Since the first discovery of Martian caves using Mars Odyssey’s THEMIS-VIS camera [1], more than 1000 possible void spaces have been identified and compiled into the Mars Global Cave Candidate Catalog (MGC³; [2]). Subsurface voids provide ample protection from surface environments that pose a harsh climate for potential biosignatures and/or extant organisms and may also provide conditions adequate for sustaining them [3]. For similar reasons, future crewed missions could capitalize on these naturally-occurring habitats ([4],[5]) and may find they also contain valuable in-situ resources. Here, we evaluated candidate caves in the MGC³ to generate the most likely viable sites for future Martian cave exploration missions.

Limiting elevations for touchdown on the Martian surface to current entry, descent, and landing technology limits, we identified 214 candidate Martian caves located within 100 km of areas at or below +1000m MOLA as putative targets of interest. Geospatial analysis was conducted using QGIS, an open-source geographic information system. We evaluated only those candidate caves that had been imaged using the highest resolution available from orbit – namely, those with High Resolution Imaging Science Experiment (HiRISE) coverage. As of May 2022, 139 of the 214 low-elevation candidate caves had corresponding HiRISE images.

To date, we have identified 9 viable candidate caves on Mars. For candidate caves with overlapping stereo coverage, digital terrain models (DTMs) were created to measure approximate pit depth and volume. Suggestions to complete additional stereo pairs and cover unimaged caves have been entered in the HiRISE database (https://www.uahirise.org/hiwish/). Confirmed low-elevation cave sites are being compiled into an atlas similar in scope to Wagner and Robinson’s [6] for the Moon and cataloged in the LROC Atlas of Lunar Pits (http://lroc.sese.asu.edu/pits/list).

References: [1] Cushing et al. (2007) Geophys. Res. Lett. 34:L17201; [2] Cushing et al. (2015) JGR Planets 120:1023–1043; [3] Boston et al. (2003) Grav. Space Bio. Bull. 16:121-131; [4] Coombs & Hawke (1992) 2nd Conf. Lunar Bases Space Activities 21st C., 219; [5] Golombek et al. (2012) Space Sci. Rev. 170:641–737; Oberbeck et al. (1969) Modern Geol. 1:75-80; [6] Wagner & Robinson (2021) LPSC No. 2530.