InSight Engineers Have Made a Martian Rock Garden
Reconstructing Mars here on Earth lets them practice setting down the lander's science instruments.
NASA's InSight lander is due to set its first science instrument on Mars in the coming days. But engineers here on Earth already saw it happen - last week.Like NASA's Curiosity rover, InSight has a full-scale
working model at the agency's Jet Propulsion Laboratory in Pasadena,
California. This sister lander, aptly named ForeSight, lets the team test all
operations before they happen on Mars.To practice how InSight will place its instruments, JPL
engineers built a Martian rock garden modeled on images from the spacecraft's cameras.
The team raked, shoveled and patted down a bed of crushed garnet intended to
simulate Martian sand. They call the shaping of this gravel-like material "Marsforming."A four-inch (10-centimeter) layer of garnet was added to
the lab space in order to match the height and slope of the surface in front of
InSight. Donning augmented-reality headsets allowed the team to project digital
terrain models of the landing site onto the test bed, checking whether they
needed to scoop more gravel into the space or smooth it out. Wood blocks marked
the perimeter of the areas where the lander's seismometer and heat flow probe
could be placed; precision cameras in the lab were used to measure each feature
they intended to replicate. It took about four hours to mimic every detail,
down to any pebbles or rocks larger than an inch (2 centimeters).Larger rocks present various challenges, both to the
lander and the instruments it will place on the planet's surface. The team has
to make sure the electrical-wire-laden tethers that connect the instruments to
the spacecraft won't catch on or abrade against a sharp rock. Thankfully,a
composite image of the workspacereleased last week revealed the
area was smooth and largely rock-free, making the job easier than expected."It's great for the science we want to do," said
JPL's Marleen Sundgaard, who is guiding the test-bed work. "It's the flat
parking lot the landing team promised us. You calculate the probability of
rocks in the area and hope the odds are in your favor."The odds have been very much in favor for InSight. "All
around us, there are rocks that were ejected from nearby craters. These can be
launched miles across the landscape, depending on the impact size," said
Nate Williams, a JPL post-doctoral researcher working with the mission.
"Thankfully, there just aren't a lot of rocks right in front of us."About 70 feet (21 meters) from the lander lies a field of
small boulders that would have made Marsforming harder, Williams said. He lent his
geologist's eye to the work, selecting rock samples for the test bed that matched
the size, shape and locations of those near InSight.By slipping on Microsoft HoloLens headsets, the team could
see a glowing red Martian surface with blue contour lines modeled on the actual
terrain in front of InSight on Mars. This was a new use of the HoloLens for JPL,
said Parker Abercrombie ofOps Lab, the JPL group that
provides this digital modeling. For the last several years, scientists with
NASA's Curiosity rover have used the HoloLens in conjunction with custom software
called OnSight. It lets them "walk" on Mars and make decisions about
what to study next.Every bit of additional realism in the lab creates a more reliable
test. The team spent this past weekend commanding each movement of ForeSight's
robotic arm, ensuring that the instrument tethers stayed clear of rocks. By
Monday morning, they had confirmed the science team's preferred placements:
about 5.4 feet (1.6 meters) directly in front of the lander for the seismometer.
The heat flow probe will be placed
roughly the same distance from the lander, but about 4 feet (1.2 meters) to the
left of the seismometer.The commands to set down InSight's seismometer are being
sent to Mars today. In a few days, Sundgaard and her team will be waiting to see
the first pictures of their work recreated robotically on the Red Planet.About InSightJPL manages InSight for NASA's
Science Mission Directorate. InSight is part of NASA's Discovery Program,
managed by the agency's Marshall Space Flight Center in Huntsville, Alabama.
Lockheed Martin Space in Denver built the InSight spacecraft, including its
cruise stage and lander, and supports spacecraft operations for the mission.A number of European partners,
including France's Centre National d'Études Spatiales (CNES) and the German
Aerospace Center (DLR), are supporting the InSight mission. CNES and the Institut
de Physique du Globe de Paris (IPGP) provided the Seismic Experiment for
Interior Structure (SEIS)
instrument, with significant contributions from the Max Planck Institute for
Solar System Research (MPS) in Germany, the Swiss Institute of Technology (ETH)
in Switzerland, Imperial College and Oxford University in the United Kingdom,
and JPL. DLR provided the Heat Flow and Physical Properties Package (HP3)
instrument, with significant contributions from the Space Research Center (CBK)
of the Polish Academy of Sciences and Astronika in Poland. Spain's Centro de
Astrobiología (CAB) supplied the wind sensors.