When aliens invade in movies, there's always a handsome, ordinary man available to save humanity from the extraterrestrial threat. Unfortunately, in real-life we can't rely on Will Smith finding his way to the last remaining air force base to save us all. Luckily, NASA is making sure we're prepared just as well as Earth in the movies.
NASA recently listed a job posting for a position called "Planetary Protection Officer." One of the main responsibilities would be making sure "organic-constituent and biological contamination" doesn't come back to earth on a space ship, which is one of the most popular set-ups for most alien invasion movies. The person would also be "responsible for the leadership of NASA's planetary protection capability, maintenance of planetary protection policies, and oversight of their implementation by NASAs space flight missions."
Unfortunately, NASA isn't going to just hire anyone to protect the planet. Candidates need "advanced knowledge of Planetary Protection" as well as experience overseeing nationally significant space programs and "skills in diplomacy that resulted in win-win solutions during extremely difficult and complex multilateral discussion." Although, you'd think that anyone with that experience would already work at NASA, but apparently not.
If you somehow fit those qualifications, you'll be happy to know that the position is well-compensated. The job pays $124,406 to $187,000 per year, which seems like a bargain for protecting the world from alien threats.