Ground controllers lost contact yesterday with the Near Earth Asteroid Rendezvous (NEAR) spacecraft, which was preparing to orbit an asteroid next month. The craft apparently shut down after its thrusters began to accelerate for a final approach.
NEAR has spent almost 3 years traveling to Eros, a large asteroid that circles the sun in an orbit between Mars and Jupiter. By pinning down the composition of Eros, planetary scientists had hoped to gain insights into the processes by which our solar system formed. "We think asteroids are the building blocks of planets, the 'hoi polloi' of the solar system," says Andrew Cheng, an astrophysicist at the Applied Physics Laboratory (APL) in Laurel, Maryland.
To get safely into orbit, NEAR needed to fire its rockets three times. The first firing, or "burn," was to help NEAR catch up with Eros on Sunday. The next burn would have slowed NEAR down, reducing the difference in speeds of the two objects to 30 kilometers per hour. The final burn was supposed to put NEAR on a path that would swing it into orbit around the asteroid on 10 January, 1999.
But something went wrong. Two minutes into the initial burn, NEAR mysteriously aborted the firing and seemed to shut itself off. It appears that the spacecraft is still intact, because ground control received a signal some 40 minutes later. But aside from that lone peep, says APL spokesperson Helen Worth, communications have been down. "We keep sending things up and nothing comes back," she says.
If NEAR does respond in the next few days, ground control may still be able to nudge the craft into orbit around Eros. Otherwise, they will have to try for a rendezvous several months later.