Abstract
Rocks around the InSight lander were measured in lander orthoimages of
the near field (<10 m), in panoramas of the far field
(<40 m), and in a high-resolution orbital image around the
lander (1 km2). The cumulative fractional area versus
diameter size-frequency distributions for four areas in the near field
fall on exponential model curves used for estimating hazards for landing
spacecraft. The rock abundance varies in the near field from 0.6% for
the sand and pebble rich area to the east within Homestead
hollow, to ~3-5% for the progressively rockier areas
to the south, north and west. The rock abundance of the entire near
field is just over 3%, which falls between that at the Phoenix (2%)
and Spirit (5%) landing sites. Rocks in the far field (<40 m)
that could be identified in both the surface panorama and a
high-resolution orbital image fall on the same exponential model curve
as the average near field rocks. Rocks measured in a high-resolution
orbital image (27.5 cm/pixel) within ~500 m of the
lander that includes several rocky ejecta craters fall on 4-5%
exponential model curves, similar to the northern and western near field
areas. As a result, the rock abundances observed from orbit falls on the
same exponential model rock abundance curves as those viewed from the
surface. These rock abundance measurements around the lander are
consistent with thermal imaging estimates over larger pixel areas as
well as expectations from fragmentation theory of an impacted
Amazonian/Hesperian lava flow.