Humans have sent about 30 landers and spacecraft to the Red Planet since the space age started. Now, we know which microorganisms might have survived the trip, says scientist Christopher Mason.
Sailing across the surface of Mars as you read this is a notable machine. Perseverance- the compact rover that safely landed on the Martian surface on 18 February this year- might only have a speed of less than 0.2 miles per hour. Still, it carries a vast range of tools, experiments, and instruments that have already made some revolutionary achievements.
Included onboard is a machine that has turned the carbon dioxide-rich Martian air into oxygen, and the helicopter, called Ingenuity, made the first-ever controlled, powered flight on another planet. The aircraft, which is the size of a tissue box, has now made three successful flights, each higher and longer than the last.
But could a spore or bacterium from Earth have accidentally been taken into space and survived the trip to flourish on Mars?
NASA and its scientists in the Jet Propulsion Laboratory (JPL) have thorough and precise protocols to minimise the number of microbes that might accidentally hitchhike on a space mission. Internationally accepted standards guide how meticulous these protocols should be, and NASA meets and exceeds them.
However, recent studies show how some organisms might survive the rigorous cleaning process and the journey to Mars and how fast microorganisms can evolve while in space.
Although, it is impossible to get to zero biomass on a rocket or spacecraft.
Microorganisms are everywhere on Earth and have been here for billions of years. They are on our bodies, inside us, and all around us.
Microorganisms carried into space can also be of more instant concern to astronauts- presenting a risk to their health if they become gummed up with colonies of microbes.