JAKARTA – NASA’s Mars rover, Perseverance, is gearing up to make another attempt, in the coming weeks. The effort is a move to retrieve Martian rock after its first attempt earlier this month didn’t go as engineers had hoped. The rover’s sampling arm worked, engineers said, but the sampling tube was empty.
Now the rover, the science lab on wheels that landed on Mars in February, will head to a new location called the Citadelle for a second chance to take its first rock samples. This time, to make sure the sample was actually collected, the engineers would wait for the sample tube images to return before being processed and stored in the belly of the rover.
“We are very pleased that the hardware worked from start to finish without any errors. And then there’s that surprise – ‘No samples? What do you mean no samples?’” said Louise Jandura, Chief Engineer for Sampling & Caching on NASA’s Perseverance team, explaining about the first attempt on Aug. 5. “So quickly, after it sank, we started investigating.”
The rock excavated by the Perseverance sample drill bit turned out to be not as strong as scientists thought. What should have been a fairly dense rock core turned out to be a brittle powder that came out of the rover’s sample tube. After finding an empty sample tube, mission staff used the rover’s camera to analyze the remains of the hole Perseverance drilled. They thought it was the mound of dust around the hole and some material at the bottom of the hole.
“That rock is not our kind of rock,” Jennifer Trosper, Project Manager at NASA’s Jet Propulsion Laboratory, wrote in a blog post on Thursday. “While we have managed to obtain more than 100 cores in a variety of different test rocks on Earth, we have not found any rock in our test suite that behaves in this way.”
The Perseverance’s seven-foot, five-joint sampling arm spans from the front of the rover towards an attractive rock with a head or tower the size of a large shoebox, at the end that weighs 100 pounds. The head contains a hollow drill bit, officially called a Rotary Percussive Corer Drill, which drills into rock and traps material in a tube, which is deposited back into the rover and processed in another tube until it is ready to be left somewhere on the Martian surface. .
The drill bit used for Perseverance’s first sampling attempt was to collect rock core. Some of the rover’s 9 drill bits are better suited for collecting regolite — a more brittle dirt-like material that engineers accidentally discovered during the first sampling attempt.
The Perseverance mission to collect up to 35 Martian rock samples is the first step in a three-pronged effort to return the samples back to Earth sometime in the 2030s. The rocks, stored in tiny chalk-sized sample tubes, will represent the first pure Martian samples ever captured and returned to Earth by humans.
Perseverance will leave the tube somewhere on the Martian surface for future NASA robots to collect and launch into Martian orbit, where another spacecraft built by the European Space Agency will capture it and carry it all the way home.
NASA engineers spent nearly a decade designing and building the rover’s sampling system, which Perseverance chief engineer Adam Steltzner describes as “the most complex and sophisticated thing we know how to build.”
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