“It was very physical work,” said Louise Jandura, JPL’s chief sampling and caching engineer, who led the testing campaign. “We were shaking with rock hammers and crowbars. A few rocks were big enough that the five of us had to hold a canvas taut to put it in the bed of our truck.
Next step: testing at JPL. One of the places where this happens is the Alien Materials Simulation Lab, a sort of service center that prepares materials for testing elsewhere in JPL.
A rock supermarket
The low building sits on a hill above the Mars Yard. The barrels at the front contain reddish dust called Mojave Mars Simulant, a special recipe for recreating the messy conditions in which rovers travel. In the back stands a concrete bunker with rock bins labeled with names that sound like Mad Libs to geologists: Old Dutch Pumice, China Ranch Gypsum, Bishop Tuff.
“I like to say that we do handcrafted material selection and preparation,” said Sarah Yearicks, a mechanical engineer who runs the lab. “Testing them is both fabrication and mad science.”
Yearicks is one of the people who chose the rocks during the excursion to the Santa Margarita Ecological Reserve. For testing on Roubion-type rocks, the Yearicks team worked with a construction-grade drill – not a core drill – and other tools, while the Jandura team used an “en flight” of Perseverance’s drill. The teams passed the rock samples back and forth, testing them in different ways.
Put to a test
Jandura’s team performed their in-flight exercise a few millimeters at a time, stopping to check that a core was still forming; if it had collapsed, they would look at the variables that might be causing it. For example, engineers changed the drill’s impact rate and the weight placed on its bit. They also tried to drill into the rock horizontally rather than vertically, in case debris buildup was a factor.
For every adjustment they made, it seemed, a new wrinkle appeared. The first was that fragile samples can still withstand the hammer drill. When the Jandura team reduced the impact force to avoid powdering the sample, the drill could not penetrate the surface. But choosing a location that withstands stronger percussion means choosing one that has probably interacted with water less.
So far, Perseverance has captured six samples of heavily weathered and water-weathered rock, and the team knows it is capable of many more. But their experience with Roubion has prepared them for some of the extremes that Mars will throw at Perseverance in the future. If they find more rocks like Roubion, the Alien Materials Simulation Lab will be ready with its menagerie of Mars-worthy materials.
Learn more about the mission
A key focus of Perseverance’s mission to Mars is astrobiology, including searching for signs of ancient microbial life. The rover will characterize the planet’s past geology and climate, pave the way for human exploration of the Red Planet, and be the first mission to collect and cache Martian rock and regolith (broken rock and dust).
Subsequent NASA missions, in cooperation with the ESA (European Space Agency), would send spacecraft to Mars to collect these sealed samples from the surface and return them to Earth for further analysis.
The Mars 2020 Perseverance mission is part of NASA’s Moon to Mars exploration approach, which includes Artemis missions to the Moon that will help prepare for human exploration of the Red Planet.
JPL, which is managed for NASA by Caltech in Pasadena, Calif., built and manages operations of the Perseverance rover.
To learn more about perseverance: