Nasa’s Perseverance rover will look for alien fossils by beaming x-rays at Mars

The rover will scan for bacteria that can cause strange rock formations similar to those on Earth

Adam Smith
Wednesday 23 September 2020 15:32 BST

Nasa’s Perserverance rover will use x-rays to look for Martian fossils, powered by artificial intelligence.

The space agency said that the rover will be equipped with ‘PIXL’ (Planetary Instrument for X-ray Lithochemistry), which is an instrument attached to the end of Perserverence’s two-meter long arm.

When it detects an important sample the tool - about the size of a lunchbox – drill into the ground to collect them and place them on the surface of Mars for collection by a future mission.

While nearly every other Mars mission has included an x-ray machine, PIXL differs from those by its ability to scan rock using a focused beam of radiation.

This can be used to find what chemicals are distributed across its surface and how many there are.

"PIXL's X-ray beam is so narrow that it can pinpoint features as small as a grain of salt. That allows us to very accurately tie chemicals we detect to specific textures in a rock," said Abigail Allwood, PIXL's principal investigator at Nasa’s Jet Propulsion Laboratory in Southern California.

On Earth, warped rocks called stromatolites were made from layers of ancient bacteria; these are examples of fossilised life that the rover will look for.

As well as its x-ray, PIXL uses a hexapox – a six-legged device – which connects to its robotic arm and uses artificial intelligence to help aim.

The rover’s arm targets a rock, and then its legs make tiny movements to it can be better scanned. Some of these movements can be as small as 100 microns, or one ten thousandth of a centimetre.

"The hexapod figures out on its own how to point and extend its legs even closer to a rock target," Allwood said. "It's kind of like a little robot who has made itself at home on the end of the rover's arm."

PIXL measures the x-rays in ten-second bursts from a single point on a rock, before tilting and scanning again.

To produce a map the size of a stamp, it needs to repeat this process thousands of times over eight or nine hours.

Moreover, because the tempratures on Mars can change by over 38 degrees Celcius over the day, the metal on Perserverence’s arm can expand and contract by up to 13 millimeters.

As such, the rover will only take measurements once the sun has set.

"PIXL is a night owl," Allwood said. "The temperature is more stable at night, and that also lets us work at a time when there's less activity on the rover."

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