It seems like an odd posting, but on closer inspection, it's really about protecting other planets from Earth-bound bacteria contamination.
NASA certainly got the world’s attention when they made an odd job posting for a “Planetary Protection Officer” to protect alien life and humankind as well, but it’s actually a fairly unsurprising move on closer inspection. The job would pay $187,000 per year, and although many headlines out there suggest that NASA is hiring someone to protect the Earth from alien invaders, what they’re really doing is trying to keep ourselves from contaminating planets with Earth-bound bacteria when we visit and endanger potential alien microbial life.
Humans have been exploring at a rapid pace in recent years, sending probes far and wide, and that pace is only likely to accelerate and will eventually include humans setting foot on Mars. That creates some potential problems as we search for life, as there’s a chance we could accidentally bring bacteria from Earth to alien planets, which would create two problems: it would contaminate any potential findings of life, as we wouldn’t know if it was actually alien life or just something we brought from Earth, and it could create a threat to alien microbial life by introducing a possible competitor.
NASA is trying to get ahead of this concern by hiring someone who would be focused specifically on these issues, hence the need for “Planetary Protection Officer.” So we’re not expecting to be invaded by little green men just yet.
“This position is assigned to Office of Safety and Mission Assurance for Planetary Protection,” the job posting states. “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. This policy is based on federal requirements and international treaties and agreements.”