A dozen asteroids 'easily retrievable' with current spacecraft A dozen asteroids can be moved closer to Earth using current rocket technology, astronomers say. A 1984 artist's conception of tethering an asteroid created for NASA. Astronomers have pinpointed a dozen near-Earth asteroids that can be moved into more accessible orbit using current rocket technology. Daniel Garcia Yarnoz and fellow researchers at the University of Strathclyde in the UK narrowed down around 9,000 near-Earth objects to those that can be moved by changing their velocity by less than 500 meters per second. By "accessible orbit," astronomers mean either the L1 or L2 Lagrange points -- about a million kilometers from Earth -- where the gravitational pull of the Sun and Earth are in balance. A total of 12 asteroids meet this criteria. One of them, known as 2006 RH120, is between 2 and 7 meters across and could be sent into orbit around L2 by changing its velocity just 58 meters per second. Researchers calculate that a single burn on February 1, 2021 would achieve the desired result, and the asteroid would then take five years to move into its new position. The team also says that a low thrust engine would be able to move up to 1500 tons into orbit. But it's not as easy as it sounds. Compared to other Lagrange points, L1 and L2 are rather unstable, and require periodic thrust to remain in orbit. And any miscalculation could send an asteroid too close to Earth for comfort, though we would only be able to move relatively small objects at first. Although private companies including Planetary Resources, funded in part with investments from Google's Eric Schmidt and Virgin's Richard Branson, are planning to mine in space, Republicans in Congress are aiming to shut down NASA's proposed asteroid retrieval mission. One NASA official has said there is widespread doubt whether a NASA Authorization Act will pass this year. The House Science, Space and Technology Committee's bill would not only cut spending and ban an asteroid capture, it would mandate that NASA begin a public-private "Advanced Composites Project," designed to "accelerate the development and certification of advanced composite materials and structures for use in commercial and military aircraft."