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| Official diagram shows the spacecraft's array of sensors and instruments.
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| Asteroid 433 Eros is currently almost directly Starry Night software.
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Spacecraft Lands on Asteroid
By Leonard David
Senior Space Writer
posted: 10:30 pm ET
12 February 2001
ET
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near_lands_010212 LAUREL, Md. -- Scientists are delighted with the high-quality, close-up images of Asteroid 433 Eros that NEAR Shoemaker spacecraft transmitted as it floated to a historic landing on the rocky surface nearly 200 million miles (322 million kilometers) from Earth on Monday, February 12."We're seeing things really well," said Joseph Veverka, NEAR's imaging team leader from Cornell University in Ithaca, New York. "The pictures are absolutely fantastic. This is a great experience to just sit here and accompany a spacecraft down to the surface." | Pictures of the Landing! | | Browse through these stunning images of the NEAR spacecraft"s descent to Asteroid Eros. | NEAR Shoemaker was not equipped with landing gear for the first-ever, odds-against spacecraft rendezvous with an asteroid. The daring dive was called for as the spacecraft's mission drew toward a successful close on February 14. The successful touchdown has emboldened scientists to consider re-launching NEAR from the asteroid's surface.Landing on an asteroid is no cakewalk, according to Robert Farquhar, NEAR mission director at The Johns Hopkins University Applied Physics Laboratory (APL) in Laurel, Maryland. Any number of things could have gone wrong. Engines could misfire; the camera could be pointed the wrong way; or the landing site terrain could have proved impossible for NEAR to navigate successfully. Touchdown took place shortly after 3:05 p.m. EST (20:05 GMT). The spacecraft fell onto the dust-laden, cratered, and rock-piled surface of Eros. "I'm happy to report the NEAR spacecraft has touched down on the surface of Eros. We're still getting some signals, so evidently it's still transmitting from the surface itself. This is the first time that any spacecraft has landed on a small body," said Farquhar. Images relayed on the way down showed what appear to be ancient craters buried below the thick, dusty face of Eros. 
| The final picture released on approach to Eros, taken at 131 yards (120 meters) from the surface. Note the data breakdown at the bottom of the image. |
In one image, a giant boulder could be clearly seen fractured in at least six pieces. As one image after another reached Earth, the spacecraft appeared to be headed towards a smooth landing surface. For over four-and-a-half hours, as engineers and scientists here at The Johns Hopkins University Applied Physics Laboratory (APL) cheered each new close-up image, the probe drifted down toward the rock of ages through a series of braking maneuvers. NEAR's mission control at The Johns Hopkins University's Applied Physics Laboratory reported the craft blasted its hydrazine-fueled motors for 20 seconds starting at 10:31 a.m. EST (15:31 GMT). The burst of rocket thrust moved the NASA probe out of its former orbit, 22 miles (35 kilometers) above Eros. "We're right on the money," cried out mission controllers as the craft drifted closer and closer to Eros. Then the probe made space history by successfully landing atop the space rock, more than 196 million miles (316 million kilometers) from Earth. NASA Administrator Dan Goldin was among the first to congratulate the team. "I'm just overwhelmed with the courage and talent it took to get to this point," Goldin said shortly after the landing. Since the car-sized NEAR Shoemaker probe began orbiting Eros on February 14, 2000 -- at a range of high- and low-altitudes over Eros -- The craft has relayed a bounty of scientific data about the asteroid, including some 160,000 images that covered all of the 21-mile- (34-kilometer-) long asteroid's surface. NEAR Shoemaker touched down in an area bordering Himeros -- a distinctive saddle-shaped depression. On the way down to the landing zone, the highest-resolution images ever taken of Eros' boulder-strewn, cratered terrain were transmitted to Earth. The telescopic camera, built for remote distance viewing, stayed in focus down to an altitude of about 0.3 mile (0.5 kilometer) above the surface. "The camera should reveal things on the surface, down to as small as a tea cup," said Clark Chapman, member of the NEAR Shoemaker science team from Southwest Research Institute in Boulder, Colorado. "The close-up images are what we're after," said Lucy McFadden, NEAR science team member from the University of Maryland in College Park. "We're going to microscopic views relative to where we started. It's just tremendous." ~ Louise Prockter, a member of the NEAR imaging team at the Applied Physics Laboratory (APL) told SPACE.com the spacecraft's last in-focus snapshots might help quell considerable debate between scientists working on the project. The nature of the regolith -- broken bits of rock and dirt that cover the asteroid -- as well as how deep and how much is there, and the origin of that material, are all questions being argued. "Looking close up might help us answer some of those questions," Prockter said. Chapman said a head-scratcher for him is to understand why so many giant boulders populate Eros. "We've been arguing between ourselves about what it means geologically," he said. "Why is it so different than the Moon? I've just got to believe that the higher resolution images are going to give us a whole bunch of additional clues as to what's really going on. There's lots of speculation." APL built and managed the NEAR mission for NASA, one of the Discovery-class of probes that initiates a cheaper, better, faster approach to space exploration. Price tag for this long-term survey of an asteroid by the econo-class spacecraft: $223 million. 
"It's a very nice way to end this mission," Prockter said. "At least we'll know exactly where the spacecraft is and what happened to it. So if there's a future mission out that way, we'll be able to look for it." When the spacecraft was launched February 17, 1996, its fuel tanks were filled with 715 pounds (325 kilograms) of fuel. After five years, exactly how much propellant remains is unknown. Precious bursts of fuel were needed to prod NEAR Shoemaker lower and lower to the surface of Eros and mission director Farquhar was not sure the probe would have enough gas to the end. Over the next two days, ground stations on Earth will keep an active ear to transmissions from NEAR Shoemaker. Roundtrip communication time between NEAR and Earth is 35 minutes. At Goldstone, California, a Jet Propulsion Laboratory (JPL) Deep Space Network antenna is to keep a lock on NEAR, with another big dish in Madrid, Spain also at the ready.Survivor for science? Now that the craft has touched down on the surface of Eros, hopes run high that NEARs onboard magnetometer can relay measurements directly from the asteroid. To date, the magnetometer has not seen anything that can be attributed to Eros. Why thats the case is a little puzzling, said Andrew Cheng, NEAR project scientist, because most of the meteorites that are thought to be related to Eros are magnetized. But whether or not the magnetometer ever picks up data from Eros, researchers are still constrained by finances. Money for mission operations runs out on February 14, 2001. Click here for more stories on asteroids and the solar system.Click here for an archive of stories on NEAR.
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