The space agency posted the listing for a planetary protection officer to its website as it acknowledged the threat we face from extraterrestrial life.
NASA wants its PPO to make sure alien matter is not accidentally brought back to Earth on spacecraft returning from space missions.
The successful applicant will also be responsible for stopping humans contaminating other planets and moons with our bacteria.
“There’s the possibility that you’re bringing something alive from another planet”
Michael Mayer, former NASA PPO
NASA and other space agencies frequently send spacecraft to Mars and Europa, one of Jupiter’s moons, as well as other worlds, which may harbour life forms we do not yet know about.
The job description says the three-year position has a top level security clearance, which means it involves handling highly sensitive information.
The successful candidate, who must be an American citizen, will be paid top dollar by NASA, earning up to £145,000 a year plus benefits.
More than 40,000 Americans have taken out insurance against being abducted by aliens.
Earlier this month a former NASA PPO, Michael Mayer, warned of the danger of bringing back “hazardous” living creatures from outer space.
Mr Mayer told NPR: “When you bring samples back there’s the possibility that you’re bringing something alive from another planet.
“In which case, you ought to be cautious and keep those samples contained until you can determine whether or not there’s anything perhaps hazardous in those samples.”
The role was first created in 1967, so that the USA complied with the International Outer Space Treaty, which lays down the basis for space law.
But it is a role unique to NASA – other countries do not have equivalent jobs.