Probe at Last Goes Silent on Asteroid Eros Updated 4:57 PM ET March 1, 2001 By Deborah Zabarenko WASHINGTON (Reuters) - The U.S. spacecraft, NEAR, which beat long odds to land on asteroid Eros, was resting in silence on Thursday after a two-week mission extension to gather bonus scientific data from the space rock's surface. The bus-sized space probe sent its last pieces of information via NASA's Deep Space Network late Wednesday, ending a five-year voyage that exceeded all expectations. "This mission has been successful far beyond what was in the original mission plan," mission director Robert Farquhar said in a statement. Besides orbiting the asteroid for a year, NEAR also got pictures of another asteroid Mathilde and was the first spacecraft ever to land on an asteroid on Feb. 12. "All this at no extra cost," said Farquhar, who is based at Johns Hopkins University's Applied Physics Laboratory in Laurel, Maryland. "When you talk about 'faster, cheaper, better,' this is what 'better' means." The $223 million mission, launched in 1996, was expected to end after its year-long scrutiny of Eros. But after accomplishing its central objective scientists decided to try to set it down on the 21-mile- (33.8-km-)long asteroid, some 196 million miles (315.4 million km) from Earth. Not only did the craft land gently enough that its solar panels continued to operate, but it continued to send back data to Earth. That allowed officials at the National Aeronautics and Space Administration to extend the mission by two weeks to receive more data from the craft's Gamma Ray Spectrometer. NASA ended NEAR's access to the Deep Space Network antenna on Wednesday but the craft's solar panels could continue to operate until April. After that, NEAR will move away from the sun's light. "FANTASTIC MISSION" Jacob Trombka, whose scientific team assesses information from this instrument, was ecstatic. "It's been quite a fantastic mission, we've been getting good data," Trombka said in a telephone interview from NASA's Goddard Space Flight Center outside Washington. The spectrometer was built to examine the gamma rays and X-rays on Eros to determine the space rock's composition. X-rays can only "look" at a fine layer of dust on the surface, while gamma ray observation can "see" perhaps 5 inches (12.70 cm) down. Most of the time, it did this from NEAR's orbit of Eros, Trombka said, despite a certain amount of distracting background noise. But after the landing of NEAR Shoemaker -- which officially stands for Near Earth Asteroid Rendezvous and also honors the late astronomer Gene Shoemaker -- scientists had a better vantage point. The chemical composition of Eros is important to astronomers seeking clues to the origins of planets like Earth. Eros may in fact be a planetesimal, one of the most primitive bodies in the solar system. "It's going to take us a couple of years to really get it down," Trombka said of the bonus scientific data collected from Eros's surface. "We're milking the things that are really easy right away ... but it's in the very small details, the things that are excruciating to pull out, where some of the most important scientific discoveries come." One benefit was instantly apparent to Trombka, though. For years, he said, there had been a push by scientists to put a gamma ray spectrometer on a planetary rover, but officials worried that the delicate instrument might not withstand the jostling over rocky terrain, such as that on Mars. By landing NEAR -- which was never meant to land -- and beaming back information from the gamma ray spectrometer, Trombka said, "We've gotten basic data to prove that this rover concept can work on planetary surfaces." More information on the NEAR mission can be viewed online at http://near.jhuapl.edu.