ISLAMABAD   -   PIXL, an instrument on the end of the Perseverance rover’s arm, will search for chemical fingerprints left by ancient microbes. NASA’s Mars 2020 Perseverance rover has a challenging road ahead: After having to make it through the harrowing entry, descent, and landing phase of the mission on February 18, 2021, it will begin searching for traces of microscopic life from billions of years back. That’s why it’s packing PIXL, a precision X-ray device powered by artificial intelligence (AI). Short for Planetary Instrument for X-ray Lithochemistry, PIXL is a lunchbox-size instrument located on the end of Perseverance’s 7-foot-long (2-meter-long) robotic arm. The rover’s most important samples will be collected by a coring drill on the end of the arm, then stashed in metal tubes that Perseverance will deposit on the surface for return to Earth by a future mission. Nearly every mission that has successfully landed on Mars, from the Viking landers to the Curiosity rover, has included an X-ray fluorescence spectrometer of some kind.