Slowly, the Eros probe attempts asteroid touchdown

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The Independent Online

Astronomers were studying the results of the first attempt to land a spacecraft on a 21-mile-long sausage-shaped asteroid called Eros last night. The attempt could herald a leap in space exploration.

Astronomers were studying the results of the first attempt to land a spacecraft on a 21-mile-long sausage-shaped asteroid called Eros last night. The attempt could herald a leap in space exploration.

The landing was scheduled for 8pm after a five-hour sequence of carefully controlled "burns" of the spacecraft's motors intended to bring it gently down at a speed of 1 metre per second (2.2mph) on to the gravel surface of the asteroid. Failure to slow the craft to a speed of 3 to 5 miles per hour could send it crashing into the surface of Eros, 196 million miles from Earth, or bouncing off into space.

"We're anticipating a really good day but we're ready for anything," Robert Farquhar, the director for the Near (Near-Earth Asteroid Rendezvous) mission, said at the beginning of yesterday's operation. "We have completed our primary mission and it's been very successful, and now we're trying to get a little bonus science. And yes, it's a little risky."

Dr David Hughes of the astronomy department at the University of Sheffield said: "The beautiful thing about this plan is that they never intended to do this in the original mission. But they realised once the spacecraft had done its scheduled mission... that they could take it out of orbit very slowly, rather than crashing it."

Astronomers around the world are waiting for the results of the mission, which are being posted daily via the internet. Anyone wanting information from last night's landing could find it at http://near.jhuapl.edu/ or at http://www.nasa.gov/.

However, controllers at the US space agency, Nasa, were cautious about the possibilities of success before the event. The 495kg (1,100lb) spacecraft was never designed to land on its target, although gravity on Eros is minuscule compared with that on Earth.

Eros is roughly the size of central London. Launched in February 1996, Near spent almost a year within 9 miles of the surface, taking photographs and mapping it.

Dr Hughes said: "It's rather like having lots of pictures of someone's skin - you want to know what lies beneath. What will be really interesting will be to see what sort of tracks the spacecraft leaves behind." That will yield information about the precise composition of the asteroid.

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