Published : Wednesday, December 19, 2018 | 5:58 PM
Engineers at the Jet Propulsion Laboratory in Pasadena last week saw how NASA’s InSight lander will set its first science instrument on Mars by working on a full-scale model of a Martian rock garden they built based on images the spacecraft took of its surroundings.
The team raked, shoveled and patted down a bed of crushed garnet simulating Martian sand to build the model Martian garden, calling the process “Marsforming.”
They started by adding a four-inch layer of garnet to the lab space at JPL to match the height and slope of the surface in front of InSight. Using augmented-reality headsets, the team projected 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, and precision cameras in the lab to measure each feature they intended to replicate.
JPL says it took about four hours to mimic every detail, down to any pebbles or rocks larger than an inch.
Right in the middle of the Martian rock garden sits a working full-scale model of the lander – InSight’s sister, which they called ForeSight – that could mimick InSight’s work on the surface of Mars, or do things in advance before the actual lander does, so JPL engineers could see and measure the possible outcome.
“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.”
And thankfully, the odds have been very much in favor of InSight. Last week, other staff at JPL released a composite image of the workspace around the lander, which revealed the area was smooth and largely rock-free, making the lander’s job of moving its instruments around much easier than expected.
“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 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 of Ops Lab, the JPL group that provides this digital modeling.
Scientists with NASA’s Curiosity rover have also used the HoloLens for several years in conjunction with custom software called OnSight. It lets them “walk” on Mars and make decisions about what to study next.
This past weekend, the JPL team commanded 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 for the instruments.
The seismometer will be placed about 5.4 feet 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 to the left of the seismometer.
On Tuesday, the team sent the commands to InSight on where to set down the seismometer. In a few days, the team should be seeing the first pictures of their work recreated robotically on the Red Planet.
For more information about InSight, visit www.mars.nasa.gov/insight.