It’s another first for NASA.

In early September, the Perseverance rover successfully used its robotic arm and drill to drill into a rock and extract a sample. It extracted a rock core about 6 cm (2 in) long and placed it inside a sealed tube. This is the first time a robotic spacecraft has collected a sample from another planet destined for a return to Earth on a separate spacecraft.

Now we wait for the eventual return of the sample to Earth.

Missions to Mars keep getting more and more complex. It’s been about 45 years since Viking 1, the first lander on Mars, made it to the surface of the planet. It sat there at Chryse Planitia for over six years, taking soil samples and searching for signs of life. Almost all scientists agree that it didn’t find any signs of life (some still think that Viking 1’s labelled release experiment showed signs of life.) But it did characterize the Martian soil and atmosphere. It also found striking evidence of liquid water flowing over the planet’s surface in the ancient past.

Look at how far Mars exploration has come since then.

This infographic shows the location of every successful mission that has landed on Mars. Image Credit: The Planetary Society
This infographic shows the location of every successful mission that has landed on Mars. Image Credit: The Planetary Society

The Perseverance mission is a triumph of complex engineering, technology, and mission design. It was built on the shoulders of previous successful NASA rover missions to Mars, especially MSL Curiosity. But it’s more ambitious than even its most recent predecessors because it’s collecting samples and caching them on the surface for eventual return to Earth.

Altogether, Perseverance is carrying 43 sample tubes. 38 of them are designated for samples, and the other five are witness tubes. The witness tubes were filled with materials prior to launch and are used to capture molecular and particulate contaminants at sampling sites. They’re designed to “… catalogue any impurities that may have travelled with the tube from Earth or contaminants from the spacecraft that may be present during sample collection,” according to NASA. Each of the rest of the 38 sample tubes can carry a sample of a solid or a sample of a gas.

Martian rock is ancient rock. The planet isn’t geologically active, so it doesn’t make any new rock. Its volcanoes are all inactive, and there is no plate tectonics. Jezero Crater, where Perseverance is working, is in the Isidis Planitia impact basin. The rocks there date back to Mars’ Noachian period, which spans from about 4.1 billion to 3.7 billion years ago. Rocks from that time period are prime targets in the search for life because Mars was much different then.

The atmosphere was thicker, and the climate was warmer. There may even have been rainfall. The rover’s first sample is from the “South Séítah” region of Mars’ Jezero Crater, and according to NASA it may contain some of the deepest, and potentially oldest, rocks in the giant crater. If there is fossilized evidence of ancient microbial life on Mars, it could very well be in the rocks that Perseverance is sampling at South Séítah.

NASA’s Mars Perseverance rover acquired this image using its onboard Right Navigation Camera (Navcam). The camera is located high on the rover’s mast and aids in driving. This image was acquired on Aug. 27, 2021 (Sol 185). Credits: NASA/JPL-Caltech.

Getting samples from Mars back to Earth
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