Rock heights and three-dimensional shapes around the InSight lander in Homestead hollow, Mars, provide new constraints on modification of the degraded 27 m in diameter impact crater and are a tool for characterizing degradation on regolith-covered lava plains on Mars. Decreasing average rock height and increasing percentage of fragments where height comprises the short axis from outside to within the hollow supports significant ejecta deflation accompanied by infilling of the interior. Rock relief outside the hollow is compared with expectations of pristine ejecta thickness and indicates up to ~40 cm of near-rim early deflation (decreasing to a few cm out to one diameter) can account for the predicted eolian component of infilling and that other eolian infilling sources are not required. Scattered rocks in the hollow are ejecta from subsequent nearby impacts and their mostly buried expression is consistent with subsequent long-term degradation estimated to be 10-4 m/Myr. Basalt rock shapes at InSight are likely similar to basalt rock shapes on Earth, but appear more platy, bladed, and elongate in a triangular form factor plot and more discoidal and bladed in an axes ratio plot. Nevertheless, addition of 10 cm to near rim rock heights to account for continued partial embedding in ejecta would result in rock shapes quite similar to terrestrial rocks. Consistency between degradation estimates based on current rock relief and rock shape after accounting for partial embedding in ejecta indicates up to ~30-40 cm early (~0.1 Ga) near-rim deflation was followed by much lesser long-term degradation.

The Bagnold linear dune field investigated by Curiosity at Mount Desert Island (MDI) is in Gale crater, north of the ~5.5 km high Aeolis Mons mound. False-color images (RGB, 2.496, 1.802, and 1.235 μm, respectively) generated from Mars Reconnaissance Orbiter (MRO) Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) data show the dune field has a reddish-brown color. A sand sheet located south of the Bagnold dunes, the Sands of Forvie (SoF), is darker and lacks the reddish-brown color. Single scattering albedo (SSA) spectra retrieved at 12 m/pixel using along‑track oversampled CRISM observation FRT00021C92 show a long wavelength (1.7 to 2.5 μm) rise for the MDI dunes. Over the same wavelength interval, SoF is characterized by a broad ~2.2 μm absorption feature, consistent with color differences between the two deposits. Checkerboard unmixing of the SSA image cube isolated spectral endmembers within the MDI and SoF. Nonlinear modeling using Hapke (2012) theory implies finer grain sizes for MDI compared to SoF, with inferred abundances of basaltic glass > feldspar > olivine > pigeonite > augite for MDI, and basaltic glass > feldspar > augite > olivine for SoF. These results are similar for the mean spectra of each region and coincide with Curiosity‑based observations that MDI contains smaller ripples with overall finer grains, while SoF has large megaripples and concentrated coarser grains on the crests. Although these deposits are only located ~2.5 kilometers away from one another, wind and local topographic controls influence their grain size and mineralogy.

Orbital and surface observations demonstrate that aeolian activity is occurring on Mars. Here we report the aeolian changes observed in situ by NASA's InSight lander during the first 400 sols of operations. Aeolian changes include creep of grains with diameters of up to 3 mm, dust removal, dark trails left by passing vortices and possible saltation. InSight has observed such changes by using, for the first time, simultaneous imaging and continuous, high-frequency meteorological, seismological, and magnetic measurements. We show that this multi-instrument combination constrains both the timing, and specific atmospheric conditions during which, aeolian changes occur. The observed changes are infrequent and episodic, consistently occur between noon and 3 pm, and are systematically associated with the passage of convective vortices. The sudden onset of peak vortex wind speeds promotes particle motion during sequences of enhanced vortex activity and stronger ambient winds. Aeolian changes are correlated with excursions in ground acceleration and magnetic field strength, suggesting vortex-induced ground deformation and charged-particle motion.