Killing many birds with one stone, that we’re borrowing from an asteroid
One of NASA’s latest announcements detailed a multifaceted plan to retrieve up to a 4 meter rock from an asteroid, and haul it back to Earth’s orbit for some hands-on time with a second, manned spacecraft. The boulder itself hasn’t been selected, as the real goal is to test the feasibility of more ambitious plans for both asteroid control and manned missions to Mars.
Phase one: Send a robot for the rock
The first phase of this mission will be launched in 2020. A probe will travel out to one of three known asteroids, testing it’s solar-powered ion engines along the way. These engines are of interest due to their efficiency, and would likely be key to future deep-space travel as a way to avoid needing to carry tons of fuel for longer trips.
Once on the asteroid, the probe will retrieve a boulder, measuring any disruptions in the asteroids trajectory. This is where the asteroid management component comes in— changing the path of any large, dangerous asteroids would be difficult if we needed to give them a big shove close to Earth. Instead, we’re looking to see how easy it is to give them a small nudge further out in space in hopes that tweaked path would build to larger shifts in trajectory when the object approaches Earth. Removing a chunk of mass, like a 4 meter boulder, would hopefully help kick off such an adjustment.
The probe will then take it’s bounty to cis-lunar orbit, meaning between the Earth and the Moon. Assuming it arrives on schedule, the boulder should be in place by 2025 and ready for the next phase of the mission.
Phase two: Astronauts at the asteroid artifact
The rock can obviously be analysed to some degree by the probe itself, but NASA will be sending a manned mission to visit it in person. The goal here is really to test the new Orion spacecraft, which theoretically is our prototype for an eventual mission to Mars. The manned ship will then rendezvous with the boulder, if only to test its maneuverability and functionality as a deeper-space vehicle.
By the end of this complicated mission, we’ll hopefully gain a lot of useful data and feedback about ion engines, moving asteroids and the Orion spacecraft. It’s kind of a big beta test that way. Oh, and we still get to keep the boulder as a souvenir (albeit in orbit).
Source: NASA announces details of its asteroid redirection mission by John Timmer, Ars Technica