Nasa is hiring someone who can defend Earth from alien contamination.

The full-time role of “planetary protection officer” will involve ensuring that humans in space do not contaminate planets and moons, as well as ensuring that alien matter does not infect Earth.

The pay is a six-figure salary: as much as $187,000 (£141,000) a year plus benefits.

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The job post reads: “Planetary protection is concerned with the avoidance of organic-constituent and biological contamination in human and robotic space exploration.”

“Nasa maintains policies for planetary protection, applicable to all space flight missions that may intentionally or unintentionally carry Earth organisms and organic constituents to the planets or other solar system bodies, and any mission employing spacecraft, which are intended to return to Earth and its biosphere with samples from extraterrestrial targets of exploration.”

The three-year position – with a chance to extend it to five years – was created after the US signed the Outer Space Treaty of 1967, vowing to “pursue studies of outer space ... and conduct exploration of them so as to avoid their harmful contamination and also adverse changes in the environment of the Earth resulting from the introduction of extraterrestrial matter”.

There is only one other full-time role like it in the world at the European Space Agency, says Catharine Conley, Nasa’s only planetary protection officer since 2014 (according to Business Insider). She is relocating to the agency’s Office of Safety and Mission Assurance.

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Under the international 1967 treaty, she explained that any space mission must have less than a one in 10,000 chance of contaminating an alien world, including making sure a robot or probe that is travelling past or photographing a planet does not cause harm.

“It’s a moderate level,” Ms Conley said. “It’s not extremely careful, but it’s not extremely lax.”

Similarly, the new employee would work to protect Earth from potential contamination by planets like Mars, which scientists say may have once been covered in water and supported life – and there may be chance of life there now.

The new hire will likely be part of the upcoming Nasa expedition to Europa, a moon of Jupiter. The $2.7bn (just over £2bn) Europa Clipper mission, approved by Congress, plans to map the moon’s surface and analyse whether it could be habitable. The probe could crash land, however, which is a circumstance the planetary protection officer should prepare for.

Candidates will be required to travel frequently – but like any job, there will be a significant amount of emails, proposals and other reading.

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Candidates must have at least one year’s experience as a top-level civilian government employee, and an advanced degree in physical science, engineering or mathematics. They must also have “advanced knowledge” of planetary protection.

The position also requires “demonstrated skills in diplomacy that resulted in win-win solutions during extremely difficult and complex multilateral discussions”. The new hire will also receive “secret” security clearance.