Over the past two decades, we’ve all gotten used to rovers exploring Mars. At least one rover has been active on the planet every day since January 4, 2004, when NASA’s Spirit rover landed in Gusev Crater. Opportunity (2004) and Curiosity (2012) followed, each on their own unique journeys of discovery. The newest and largest of these robotic explorers, Perseverance (2021) features a state-of-the-art in-situ resource-use experiment to extract oxygen from the atmosphere, an escort helicopter to explore the path ahead, and an array of unparalleled geological instruments . But what really sets Perseverance’s mission apart is that, for the first time, it is collecting samples of Martian rocks to bring them back to Earth.
As advanced as Perseverance’s scientific instruments are, nothing beats the ability to examine samples up close in a laboratory here on Earth. So Perseverance makes a rock collection. It takes samples on its travels through the Jezero crater and leaves caches of the samples for a future mission to collect and return to Earth (sometime in the mid-2020s).
At least that’s the plan. But space exploration is never easy. As common as rover activities on Mars have become in recent years, the Red Planet continues to surprise mission planners. Earlier this month, Perseverance made its first attempt to collect a sample in one of its 43 titanium collection tubes. After drilling the sample core, the team was shocked to find that the sample tube remained empty and was nowhere to be found on the ground around the rover or in the borehole.
The empty core hole after a sampling attempt on August 6, 2021. Credits: NASA / JPL-Caltech / MSSS
The rock Perseverance was drilling turned out to be much softer than previously thought, and the rock only crumbled to powder under the drill. Thomas Zurbuchen, Assistant Administrator of NASA’s Science Mission Directorate, told reporters, “While this is not the hole-in-one we were hoping for, there is always risk in breaking new ground … I am confident we have the right team working on it. and we will persistently work towards a solution that will ensure future success. “
This week this team is ready for a second try. Perseverance has positioned itself next to a new ledge nicknamed “Rochette”. Rochette is about 455 meters from the first sampling point on a ridge called the Citadelle. This outcrop has withstood millennia of wind erosion, suggesting it should withstand the Perseverance drill bit more easily.
Nicknamed Rochette, the rock in the center of this image is Perseverance’s next sampling target. Photo credit: NASA / JPL-Caltech.
“There are potentially older rocks ahead of us in the South Séítah region, so this younger sample can help us reconstruct the entire Jezero timeline,” said Vivian Sun, a mission scientist at NASA’s Jet Propulsion Laboratory.
The team is also making some changes to their sampling process this time around. Before attempting to take a sample from Rochette, Perseverance will use its robotic arm to “grind” the surface of the rock and study how it reacts. Then, during the sampling process, the rover’s Mastcam-Z camera looks inside the canister to make sure it’s full before sealing it.
As for the “empty” canister from the first trial – Perseverance will also hold it for the return to Earth – it doesn’t contain any stones, but it does contain a sample of the Martian atmosphere that might be just as interesting to learn.
This is not the first time that the rocks and soil of Mars have caused problems for NASA’s robotic missions. Curiosity had to operate for a long time with a broken drill. As early as 2008, the Phoenix lander found the Martian soil “sticky” and difficult to work with, and recently the “mole” of the InSight lander, which was supposed to drill two meters underground to examine the interior of the planet, could not do more than dig a few tens of centimeters because the soil did not offer the expected friction.
A close up of Rochette. Photo credit: NASA / JPL-Caltech.
These challenges keep reminding us that Mars really is a completely different planet and that geology doesn’t always react the way we Earthlings would expect. But with luck and careful planning, Perseverance has a good chance of sampling this week. This brings the dream of a Mars sample return mission one step closer to reality.
Learn more: https://www.jpl.nasa.gov/news/nasas-perseverance-plans-next-sample-attempt