A rock core is visible inside the Perseverance rover's sample tube, September 1, 2021.

NASA's Perseverance rover has drilled into a rock in Mars' Jezero Crater and emerged with a finger-sized core of alien stone.

To confirm its catch, the rover beamed photos back to mission controllers on Thursday showing its sample-collection tube filled.

"Now that is one beautifully perfect cored sample, if I do say so myself," Adam Steltzner, the rover's chief engineer, said on Twitter.

NASA hopes this core will be the first of many - the rover is carrying 43 such tubes. In about a decade, the agency plans to send another spacecraft to gather those samples and launch them back to Earth. Scientists suspect that, if they can get their hands on Jezero Crater's rocks, they may find the first strong evidence of ancient alien life.

The Perseverance rover photographed this Mars rock after drilling a sample core from it, September 1, 2021.

That's because, more than 3.5 billion of years ago, a river spilled over the edge of this crater and filled it with water. So if Mars ever hosted microbial life, Lake Jezero would be the place to find evidence of it. The river would have carried clay and minerals into the lake, where those materials would have fallen to the bottom - possibly trapping microbes and enshrining them as fossils in sedimentary stone.

To get its first taste of that kind of stone, Perseverance drilled into a different rock last month. But its sample tube came up empty. There was a hole in the rock, but no core to be found.

After some head-scratching, NASA scientists and engineers determined that the rock had simply crumbled into a fine powder. It was too porous and weak to withstand the rover's drill.

Perseverance used its sample-collection arm to try coring a Mars rock on August 6, 2021.

So Perseverance drove south, to a field of rocks that appeared hardier. The NASA team chose a rock, nicknamed it "Rochette," and instructed the rover to dust off the spot where it would drill. On Wednesday, the robot made its second attempt to collect a sample. This time, the tube came up full.

Now Perseverance is set to spend the next year and a half roaming the floor of Jezero Crater, climbing the ancient river delta, and drilling new samples as it roams.

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