Why Mars matters Mar 03,2021 - Last updated at Mar 03,2021 NEW YORK — The Perseverance rover, which landed on Mars this month, marks a new leap toward answering fundamental questions about our solar system, including where else we might find DNA. The rover will roam the surface of Mars looking for signs of life, make its own oxygen, launch a helicopter, and collect soil and rocks for a follow-up mission in 2028. If all goes as planned, NASA, with the help of European Space Agency (ESA) spacecraft, will return soil samples in the spring of 2032, the first Martian material to visit Earth. Finding DNA on Mars would not be a complete surprise. Though Perseverance was constructed in the Spacecraft Assembly Facility (SAF) clean room at NASA’s Jet Propulsion Laboratory (JPL), even that setting cannot be made 100 per cent free of background microbial or human DNA. We have known about “microbial hitchhikers” since the very first interplanetary missions in the 1960s, when scientists such as Carl Sagan highlighted the problem. It is a persistent, unavoidable risk of space science. Because scientists must build the spacecraft one layer at a time, shedding skin and droplets of saliva over years of construction, it is almost certain that a little bit of California DNA just landed on Mars.