Rather than sending astronauts out to an asteroid -- the next step in the U.S. human spaceflight program -- a group of scientists wants to instead bring an asteroid back to Earth.
Ideally, they'd like something similar but much smaller than asteroid 2012 DA14, which will soar closer to Earth at 2:24 p.m. EST Friday than any other known object of its size.
"We're interested in learning how to bring back a 350- to 1,000-ton asteroid. This one is 140,000 to 150,000 tons," Paul Dimotakis, a professor of aeronautics and applied physics at the California Institute of Technology in Pasadena, Calif., told Discovery News.
The idea is not to actually land an asteroid on the planet's surface, but to put one into orbit around the Earth or the moon and then send astronauts or robots to retrieve samples.
For now, the show-stopper isn't technology, it's finding a suitable target.
"Things that are that tiny are very hard to see. Their orbits are very close to that of the Earth," Dimotakis said.
DA14 is expected to pass about 17,200 miles above Earth's surface, said NASA astronomer Donald Yeomans, with the Jet Propulsion Laboratory in Pasadena.
That's the closest approach of any known object of its size, but it likely won't be the last.
Only about 10 percent of the estimated 100,000 objects that fly near Earth have been found, a situation Dimotakis likens to walking across a busy highway where only one in 10 cars have their headlights on.
Asteroid DA14, for example, was only discovered last year, and it was found serendipitously by a group of amateur astronomers.
"This is a shot across the bow," Dimotakis said. "It illustrates the challenge of the observation campaign which is now in progress."
"It's a good thing it's not hitting us, because truth be told there's nothing we could do about it except possibly evacuate, which is not going to be easy given the uncertainty about where the impact would take place. We would essentially take the hit," Dimotakis said.
Whether for security, science or potential commercial mining operations, the first step is to find the asteroids that swarm around Earth. That could begin by re-searching archived digital images from telescopes, such as Caltech's Palomar Observatory.
"We can scan what is already on the record, then if we discover anything, we can set up software controls so if something is detected it can be tracked in real time," Dimotakis said.
Though DA14 is about 45 meters in diameter, it is too dim to be seen without a telescope or binoculars. NASA plans a half-hour broadcast on NASA Television and on its website, beginning at 2 p.m. EST, which will include near real-time views of the asteroid from observatories in Australia, weather permitting.
The Slooh space camera plans a webcast on Slooh.com beginning at 9 p.m. EST that incorporates views from observatories on the Canary Islands and in Arizona.