ASTRONAUTS are lining up to be candidates for an extreme trip of a lifetime.

NASA announced this morning that it plans to land astronauts on an asteroid by 2025.

And while "planetary defence" is the most exciting of several reasons why NASA could be undertaking the mission, the agency says it isn't planning a Bruce Willis kamikaze mission.

That kind of drama and intrigue is reserved for Hollywood, said Dr Paul Abell, NASA’s lead scientist for planetary small bodies.

“The Armageddon film with Bruce Willis was a very fun movie but not exactly the most scientifically accurate”, Dr Abell told news.com.au.

“This is going to be an exciting endeavour but not quite that dramatic. It’s going to happen a little bit more slowly.”

The mission is designed to garner new information about the potential to harvest resources from asteroids, as well as the origin of life as we know it.

“This exploration incorporates both the science, exploration, resource utilisation and planetary defence all in one go,” Dr Abell said.

“We can do things that will further humanity’s forays into space — going to Mars and expanding the human presence in the solar system.

“We also expand our scientific horizons in learning about what’s out there in the solar system.

“And also being able to live off the land – resource utilisation is going to be key."

Oh, and did we mention planetary defence?

“Very important to the general public is the aspect of planetary defence and making sure we don’t have an impact and making sure our grand-children or great grand-children don’t have to worry about an asteroid coming in and hitting the planet," Dr Abell said.

NASA won’t be able to land a spacecraft on the asteroid directly however, as most asteroids have a very weak gravitational field.

That makes things a little tricky, because asteroids travel at speeds ranging from 54,000 to 90,000km/h.

The spacecraft is going to have to travel at the exact same speed as the asteroid while the astronauts deploy to and from it to collect samples and conduct experiments.

"One of the things we are looking at in earnest is seeing if we can anchor or attach or tether equipment and astronauts to the surface," Dr Abell said.

Though they’ve had plenty of volunteers, NASA is yet to pick a team of astronauts and do not plan on doing so for at least another five years.

But if you're thinking of applying for the job, know this — you have to be an experienced spacewalker.

"It takes a tremendous amount of strength upper body strength and endurance. It's very, very tiring," Dr Abell said.

"You’re probably going to have to be doing EVAs (extra vehicle activities) on the order of maybe 8 to 12 hours at a time on these missions, so the astronauts really have to be fit both physically and mentally for what they are going to be doing."

NASA hasn't yet chosen an asteroid on which to land yet either, but they have it narrowed down to a group of 1200 “potentially hazardous” asteroids that present a potential risk to Earth and its inhabitants.

"If an object is potentially hazardous, it's because it makes close approaches to the Earth," Dr Abell said.

"So the objects that are potentially hazardous, even though they’re present a hazard, they also present the best opportunity for us to go out and get them and learn about them."

Originally published as Hands up who wants to ride an asteroid?