The Current

Space travel could contaminate Mars with human germs, warns professor

Astronauts have always had rules that stop them bringing contamination back to Earth from outer space, but now some experts are arguing we need to protect other planets from the human germs we bring with us.

Martian life could be mistaken for 'something that a dirty human being brought with them' says Todd Huffman

NASA's Curiosity rover on the surface of Mars. Robotic missions to other planets pose a smaller risk of contaminating those new environments. (NASA/JPL via Reuters)

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An Oxford professor is calling for a "temporary moratorium" on human missions to Mars, until we can find a way to travel there without contaminating the red planet's environment.

"We're covered with bacteria and various organisms that live with us," said Todd Huffman, a professor of particle physics at Oxford University.

"If we send a human being to the planet Mars you're basically bringing a massive bag of various living organisms from our planet and depositing them on the Martian surface," he told The Current's guest host Laura Lynch.

That could potentially contaminate native organisms on Mars, he said, or any other planet capable of supporting life.

"And then there'd always be the question: did you actually find life on Mars, or did you find something that a dirty human being brought with them?"

In the early days of space travel, returning astronauts spent weeks in quarantine to ensure they weren't bringing harmful bacteria back with them. Those guidelines were out in the Outer Space Treaty, a 1967 agreement that established rules for space-faring nations.

A new report, commissioned by NASA, argues that current planetary protection policies need to be revised, not just to protect Earth, but to protect other planets from us.​

Astronaut Michael Barratt. (NASA)

NASA's planetary protection officer Lisa Pratt, however, is less certain that human detritus could be mistaken as Martian.

"If there were to be a Martian lifeform, and it's had four billion years to evolve and adapt to the harsh present-day surface conditions on Mars. I don't think it will look like a terrestrial form of life," she told Lynch.

"I think it will have a distinctive extraterrestrial signature."

Pratt's job is to make sure the obligations of Outer Space Treaty are me. Contamination is controlled both coming back from space, and when humans leave the atmosphere.

Any extraterrestrial expedition, she says, will leave "a human signature, of all the associated microbes," explained Pratt. The contamination could come from the people themselves, or equipment and supplies they bring with them.

The Acidalia Planitia plain on Mars. The 'Hollywood-esque scenario' of humans becoming infected by bacteria on other planets would raise ethical questions, said Lisa Pratt. (Reuters)

Any potential life on Mars could be so sparse that the arrival of human — their bodies teeming with bacteria — could overwhelm it or make it harder to find.

"Perhaps, in the Hollywood-esque scenario, we would inadvertently contaminate the humans with an extraterrestrial, Martian form of life, before we even knew it was there," she said.

That scenario raises the ethical dilemma of how to quarantine those human explorers.

Every space-faring nation is having those hypothetical conversations, she said, but that won't stop exploration.

"I think it is a bit naive to think that we could simply say: thou shalt not go because there is extraordinary science to be done," she said.

"There is also clearly a human passion for exploration and discovery, and somehow we have to balance those those needs."

Listen to the full discussion near the top of this page.

Written by Padraig Moran. This segment was produced by The Current's Danielle Carr.


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