Mars Lander
© NASA/UPI/Newscom/File
The robotic arm on NASA's Phoenix Mars Lander scooping Martian soil samples
Amid the latest exploration and search for life on Mars, a Cornell scientist wonders what kind of microbe humans could have accidentally "carried into space and survived the trip to make its new home on Mars."

Cornell University geneticist Christopher Mason wrote in an May 10 piece for the BBC that life discovered on the red planet might have actually originated on earth in NASA labs, despite thorough on-site cleaning procedures and spacecraft assembly in specialized rooms.

Spacecraft, like the Perseverance Rover, are built in meticulously sterilized rooms piece by piece with each component cleaned before being added. This should theoretically ensure that no bacteria or organism survives the assembly process, according to Mason.
"Filtration systems in the spartan rooms offer an extra layer of protection so only a few hundred particles can contaminate each square foot. But, it is almost impossible to get to zero biomass. Microbes have been on Earth for billions of years, and they are everywhere. They are inside us, on our bodies, and all around us. Some can sneak through even the cleanest of clean rooms."
Mason says his own theoretical research has shown evidence of microbes that have the potential to be problematic during space missions, as the microbes contain increased genes that make them better able to resist radiation and cold environments.
"It turns out that clean rooms might serve as an evolutionary selection process for the hardiest bugs that then may have a greater chance of surviving a journey to Mars."
Researchers' findings, according to Mason, might cause what is called "forward contamination." Forward contamination is where travelers take something intentionally or unintentionally from one planet to another. Mason adds that new organisms "can wreak havoc" on a new ecosystem.

Mason noted that forward contamination is also "undesirable from a scientific perspective." A microbe, originally from earth, could look quite different once exposed to the environment of another planet.
"Microbes could potentially hitchhike their way to Mars, even after pre-launch cleaning and exposure to radiation in space, and their genomes may change so much that they look truly otherworldly, as we have recently seen with microbes that evolved on the International Space Station. If these types of species were found in the Martian soil, it could potentially spark misguided research into the universal features of life or Martian life."
There is a possibility that signs of life found on Mars could have actually originated on earth, Mason says. But scientists will be able to distinguish between life originating on another planet and something born on earth and adapted elsewhere.
"Eventually, humans will set foot on Mars, carrying the cocktail of microbes that live on and inside our bodies with them. These microbes too will likely adapt, mutate, and change. And we can learn from them too.

"They may even make life on Mars more tolerable for those who go there, since the unique genomes adapting to the Martian environment could be sequenced, transmitted back to Earth for further characterisation, and then utilised for therapeutics and research on both planets."