A nine-year-old boy has received an encouraging response from NASA after he applied for the role of planetary protection officer.

The job was listed this week as the space agency seeks help to protect Earth from aliens.

In technical terms, the officer would assist with the "avoidance of organic-constituent and biological contamination in human and robotic space exploration."

The job advert notes that "space flight missions may intentionally or unintentionally carry Earth organisms and organic constituents to the planets or other solar system bodies."

Among the first applicants for the role was nine-year-old Jack Davis. He wrote to the space agency to explain:

Letters exchanged between NASA and space enthusiast Jack Davis, a fourth-grade student in New Jersey. Image: NASA

Dear NASA,

My name is Jack Davis and I would like to apply for the planetary protection officer job.

I may be nine but think I would be fit for the job.

One of the reasons is my sister says I am an alien also.

I have seen almost all the space and alien movies I can see.

I have also seen the show Marvel Agents of Shield and hope to see the movie Men in Black.

I am great at video games.

I am young, so I can learn to think like an Alien.

Sincerely,

Jack Davis

Guardian of the Galaxy

Fourth Grade"

Jack in turn received a letter from the eminent Dr James L Green, the director of NASA's planetary science division:

Dear Jack,

I hear you are a 'Guardian of the Galaxy' and that you're interested in being a NASA Planetary Protection Officer. That's great!

Our Planetary Protection Officer position is really cool and is very important work. It's about protecting Earth from tiny microbes when we bring back samples from the Moon, asteroids and Mars. It's also about protecting other planets and moons from our germs as we responsibly explore the Solar System.

We are always looking for bright future scientists and engineers to help us, so I hope you will study hard and do well in school. We hope to see you here at NASA one of these days!

Sincerely,

Dr. James L. Green

Director, Planetary Science Division

The nine-year-old also received a phone call from NASA's planetary research director, Jonathan Rall, at NASA Headquarters in Washington, to congratulate him on his interest in the position.

NASA stated that although the planetary protection officer position "may not be in real-life what the title conjures up," it plays an important role in "promoting the responsible exploration of our solar system by preventing microbial contamination of other planets and our own."

The successful candidate will be paid between $124,406 and $187,000 and applications for the position will remain open until 14th August.