Washington

Next Monday, 12 February, NASA scientists will be celebrating the success of the Near Earth Asteroid Rendezvous (NEAR) mission — even if the spacecraft crashes and disintegrates on the surface of the asteroid on which it will attempt to land.

This is because NEAR has already surpassed its original goals. The attempted landing, according to NASA spokesman Don Savage, is merely a chance to collect “bonus science” in the form of extremely high-resolution photographs that the spacecraft will take as it descends towards 433 Eros.

Attractive forces: will NEAR survive the gravitational pull of Eros? Credit: NASA / JHUAPL

“Even if we just get one photograph,” Savage says, “it will be more than we expected.” There is an outside possibility that NEAR's instruments will survive a landing, because 433 Eros has only a weak gravitational pull. But NEAR was not designed for landing, and no one has tried landing a spacecraft on an asteroid before.

NEAR Shoemaker, as the mission is formally known, was launched five years ago. After a two-billion-mile journey, it entered the orbit of 433 Eros, one of the largest near-Earth asteroids. The spacecraft then began collecting data for the first long-term, close-up study of an asteroid. It focused on mass, structure, composition, geology and magnetic field, in a search for clues to the origins of the Earth, the other planets, and possibly the entire Universe.

According to NASA, NEAR has collected 10 times more data than originally planned during its one-year orbit of 433 Eros, including indications that the asteroid is older than Earth. But some of the data have been mystifying, such as the disintegration of boulders on the asteroid's surface. Such questions prompted scientists at NASA and Johns Hopkins University's Applied Physics Laboratory, which built the craft and has managed the mission, to try for a closer look.

The success of the $240 million mission marks a welcome contrast with the failures and cutbacks in NASA's outer-planet programme during recent years.

Mark Sykes, chair of the American Astronomical Society's division of planetary sciences, supports the NASA plan: “Why just turn the thing off at the end when you can do something that's higher risk and you can gain from it?”

→http://near.jhuapl.edu