An asteroid the size of a house will shave past Earth at a distance of some 44,000 kilometres (27,300 miles) in October, inside the Moon's orbit, astronomers said Thursday.
The space rock will zoom by at an eighth of the distance from the Earth to the Moon -- far enough to just miss our geostationary satellites orbiting at about 36,000 kilometres, according to the European Space Agency (ESA).
"It will not hit the Earth," said Detlef Koschny of ESA's "Near Earth Objects" research team. "That's the most important thing to say."
The asteroid, dubbed TC4, first flitted past our planet in October 2012 -- then at about double the distance before disappearing. It is about 15-30 metres (49-98 feet) long.
Scientists expected the asteroid to return for a near-Earth rendezvous this year, but did not know how far.
Now, the European Southern Observatory's Very Large Telescope in Chile has managed to track down the rock and determine its distance.
"It's damn close," said Rolf Densing, who heads the European Space Operations Centre in Darmstadt, Germany.
"The farthest satellites are 36,000 kilometres out, so this is indeed a close miss," he told AFP, adding it was nothing to lose sleep over.
"As close as it is right now, I think this prediction is pretty safe... meaning that it will miss."