What are Near Earth Objects?

Comets, asteroids and other leftover matter from the formation of the Solar System that floats into the vicinity of Earth is an NEO.

Bonestell painted NEOs in the form of comets, here passing by the dark side of the Moon. Many NEOs are known to orbit near us on a consistant basis.

Spaceguard and NASA's JPL have been tracking them since 1994's cometary impact with Jupiter put the possibility of catastrophe in the public (and congressional) imagination.

But, did anyone imagine visiting one?