NASA Ends Contact With Spacecraft on Asteroid

After a mission that exceeded expectations, the hardy spacecraft that became the first man-made object to land on an asteroid was shut down this week by NASA scientists at JPL and Johns Hopkins University.

On Feb. 12, the 1,100-pound NEAR spacecraft gently landed on the asteroid Eros and continued to send signals to surprised and delighted scientists.

NASA extended communications with the NEAR mission by two weeks beyond its scheduled Feb. 14 conclusion to allow the spacecraft to take close-up readings of the asteroid’s surface.

That reprieve ended Wednesday night when, in effect, NASA’s Deep Space Network hung up on the spacecraft.

Eros is about 196 million miles from Earth, and the spacecraft signal is too faint for conventional antennae.

Helen Worth, a spokeswoman at the Applied Physics Laboratory, said signals from NEAR were getting weaker and weaker because sunlight was dimming at its landing site. The craft operates on electricity made by its solar panels. She said the site would be in darkness in a month, cutting off all power. Scientists at that lab and at JPL were in charge of the mission.

She said scientists may try to contact NEAR again in two years, but engineers doubt the effort can succeed because the spacecraft will have spent months in temperatures as low as minus 231 degrees.

NEAR, the Near Earth Asteroid Rendezvous, was designed to operate only while flying in space, but lab officials decided to end its yearlong orbit of Eros with a touchdown on the asteroid’s barren surface.

They had expected the landing to smash the craft and silence its signal. Instead, NEAR gently came to rest, propped like a tripod, with its solar panels pointed at the sun. It continued to send and receive signals, though at a reduced data rate.

The gentle landing was a bonus for scientists. It left a NEAR instrument, the gamma ray spectrometer, just 4 inches from the asteroid surface. NASA extended the mission to enable APL researchers to gather new data from the instrument.

Worth said scientists got seven full days of readings and should be able to determine, in great detail, the chemistry of the asteroid.