T246 The InSight Mission to Mars: Geology of the Landing Site

Wednesday, 25 September 2019
8:00 AM - 12:00 PM
Room 232BC, North Building

GEOLOGY OF THE INSIGHT LANDING SITE, MARS

Paper number: T246-5
Program: Technical Sessions
Time: 9:05 AM – 9:20 AM

Authors

Abstract

The Interior Exploration using Seismic Investigations, Geodesy and Heat Transport (InSight) spacecraft landed successfully on Mars in western Elysium Planitia at 4.502°N, 135.623°E at an elevation of -2613.43 m on Nov. 26, 2018. Color panoramas from the lander show it is located within a quasi-circular depression, interpreted to be a degraded ~20 m diameter impact crater, informally named Homestead hollow, with a smooth pebble rich surface adjacent to a slightly rockier and rougher terrain. Ten 1-10 m diameter impact craters can be seen within 20 m of the lander. Some of these craters have very little relief and are filled with fine grained material. Farther afield, bright circular patches suggest soil filled, degraded craters (hollows) are common. Rock abundance is very low in the hollow (1-2% for rocks >10 cm diameter) and ~2 times higher in the rockier terrain. Pulsed retrorockets removed surficial fine-grained dust to create a dark spot (40 m diameter) and scoured loose sand and granules up to 5 m from the lander. Three pits ~10 cm deep beneath the lander have steep slopes (greater than the angle of repose) whose walls are composed of small rocks and pebbles weakly cemented in a finer-grained matrix (duricrust). Smaller clods and pieces of this material are scattered within the pits and adjacent areas and appear to bury one of the footpads. These observations suggest a near surface stratigraphy of surficial dust over thin cohesionless sand, underlain by duricrust, with poorly sorted, cohesionless sand and rocks beneath. Orbital and lander radiometer measurements of thermal inertia are consistent with a surface dominated by fine sand size particles, which is consistent with the very low rock abundance. The surface appears modified by impact, eolian and mass wasting processes with craters in various stages of degradation and dusty eolian bedforms (suggesting relative inactivity). These observations are consistent with expectations made from remote sensing data prior to landing indicating a surface composed of >3 m thick impact-fragmented regolith overlying Hesperian basalt flows that would be similar to the Spirit landing site.

Geological Society of America Abstracts with Programs. Vol. 51, No. 5

doi: 10.1130/abs/2019AM-336461

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