NASA's study of NEOs provides important clues to understanding the origin of our solar system.

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The exploration of NEOs would be useful for NASA in the development of its Orion spacecraft that is being developed for its lunar missions.

CNN: Space's threat to civilization

It may be good to go back to the moon, but if you're going there for resources there are potentially far richer reserves on NEOs and they're easier to get to.

CNN: Space's threat to civilization

Leading the campaign for a global response to NEOs and a closer exploration of their physical make up is former astronaut Russell Schweickart, who piloted the lunar module of Apollo 9 in 1969.

CNN: Space's threat to civilization

NEOs than all other telescopes on Earth combined.

ECONOMIST: A large asteroid sweeps by Earth. Where are the others?

In 2005 Schweickart successfully campaigned for NASA to take the issue of NEOs seriously, the result has been a number of NASA centers developing prospective plans to land a spacecraft and even astronauts on an asteroid.

CNN: Space's threat to civilization

The NASA Near Earth Objects (NEO) Program at the agency's headquarters in Washington, manages and funds the search, study, and monitoring of NEOs, or asteroids and comets, whose orbits periodically bring them close to the Earth.

ENGADGET: PSA: Asteroid 2012 DA14 will pass the Earth at 2:00pm ET Alt

NEOs which are bigger than 140 metres.

ECONOMIST: A large asteroid sweeps by Earth. Where are the others?