Contact with the Maryland-built NEAR spacecraft was lost late yesterday. The problem began shortly after the start of what was to have been a 20-minute rocket burn intended to speed NEAR toward a Jan. 10 rendezvous with the asteroid Eros.
"We're concerned, but not panicking," said mission manager Robert W. Farquhar of the Johns Hopkins University's Applied Physics Laboratory in Laurel. Hopkins scientists were working overnight to restore communications.
The 5 p.m. rocket firing appeared to have started on time, but shut down almost immediately, Farquhar said. "It will take quite a while to contact it again."
The maneuver was designed to increase NEAR's speed by 1,500 mph so that it could catch up to the faster-moving asteroid. If controllers can't restore contact and solve the problem in one to two days, NEAR would fly past Eros. It would take some pictures, but without going into orbit, Farquhar said. The mission might even be saved after that, but the solution could cost precious fuel or delay the arrival at Eros.
Additional burns were planned for Dec. 28 and Jan. 3. They were designed to bring NEAR (Near Earth Asteroid Rendezvous) to within 630 miles of Eros by Jan. 10. By then, its speed relative to the asteroid should be 19 mph.
NEAR's engine had not been fired since its last maneuver, in July 1997. Farquhar said radio contact can be temporarily disrupted by an engine firing if the motion pushes its antennas out of alignment with the Earth.
If the problems are solved, NEAR will slip into orbit around Eros on Jan. 10 for the first extended, close-up study of an asteroid. It will spend a year sending back photographs of the 25-mile-long asteroid, and data on its structure and chemical composition.
At the end of its mission, NEAR's orbit may be lowered to within a few miles of Eros' surface. Controllers might decide to land it.
Asteroids are small, rocky objects orbiting the sun.
NEAR was designed and built at APL, and its $211 million mission is being controlled from APL's Laurel campus. It was launched in February 1996, the first mission in NASA's "faster, better, cheaper" Discovery series.
Follow NEAR's progress on the Internet at http: //near.jhuapl.edu
Pub Date: 12/21/98