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American Spacecraft Landed on Asteroid Eros
Spacecraft Makes First Landing on Asteroid
The unmanned Nasa spacecraft landed on an asteroid called Eros, nearly 200 million miles from Earth, on Monday.
The Near (Near Earth Asteroid Rendezvous) Shoemaker was only designed to orbit Eros, rather than land.
But mission controller Dr Robert Farquhar decided to take the risk of trying to land the craft after it had orbited Eros for a year - and it touched down so smoothly that its radio beacon is still sending out a signal.
Nasa's chief scientist was stunned by the achievement.
"They made a spacecraft that was only designed to orbit and then they put it down on an asteroid and it's still working," said Ed Weiler of Nasa.
"That's amazing," he said.
The probe sent close-range pictures showing detail on the surface of the asteroid for a year before it landed on the surface.
Scientists at the Johns Hopkins University Applied Physics Laboratory, who developed the craft, were delighted by the quality of the images, describing them as "unbelievable".
Monday's "controlled crash" ended a five-year journey by the craft, one of the first of Nasa's "faster, better, cheaper" missions.
The vehicle was designed, built and launched in just over two years, a remarkably fast operation by Nasa standards.
The Near mission has been seen as a great success and the data sent back from the landing are seen by Nasa scientists as "bonus science".
Images from the spacecraft were broadcast live on the internet.
During its year-long orbit of the asteroid, Near transmitted some 160,000 images of the rocky surface.
Asteroids, material left over from the formation of the Solar System, are rocky and metallic objects that orbit the Sun but are too small to be considered planets.
Because asteroids are material from the very early solar system, scientists are interested in their composition.
Data on the object could also be useful well into the future, as there is a chance that Eros could collide with the earth in roughly 1.5m years.
The probe that landed on Monday will not be able to provide detailed information from the surface.
Its solar panels are still generating enough electricity to enable the probe to send out a signal, but the signal itself contains no data.
It is just a hum to let mission control know the orbiter is still "alive".
It should continue transmitting for another three months or so, until the natural motion of the asteroid takes Near Shoemaker's solar panels out of the sunlight and its battery dies.
But, because the mission officially ends on Wednesday, even if the probe continues to transmit for months to come, no one will be listening to Eros after Valentine's Day.
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