Scientists will use a radar to study the 2012 DA14 asteroid, as it flies past the Earth tonight, to learn about its structure and composition.
They hope to use the information to help them plan in the event of another incoming space rock.
Video source: NASA
Scientists are looking at ways to 'nudge' an asteroid if it was a threat to Earth, as blowing it up would only result in debris falling to Earth, they said.
Tonight an asteroid will approach Earth, passing closer than ever before.
More top news
Andy Murray has beaten Belgian David Goffin to win the Davis Cup for Great Britain for the first time since 1936
Mercedes' Nico Rosberg has won the season-ending Abu Dhabi Grand Prix, with team-mate Lewis Hamilton coming second
Celebrities and campaigners have joined a huge rally urging world leaders to agree tough measures to curb global warming