near_instrument_000608 Controllers of the first robotic mission to orbit an asteroid have turned off one of the spacecrafts six instruments after it unexpectedly overheated and ceased returning data to Earth about Asteroid 433 Eros surface minerals.
The Near-Earth Asteroid Rendezvous (NEAR) team switched off the instrument this week after it continued to draw excessive amounts of power. The problem on the near-infrared spectrometer (NIS) first cropped up on May 13, when it stopped transmitting data culled from the potato-shaped rock.
Controllers switched off NEAR's near-infrared spectrometer after it overheated.
Helen Worth, a spokeswoman for The Johns Hopkins University Applied Physics Laboratory, which manages the mission on NASAs behalf, said on Wednesday that scientists doubt the instrument will resume working.
NEAR has been in a slow dance of an orbit around Eros, which is about twice the size of Manhattan, since February 14. During that time, the NIS has mapped about 60 percent of the asteroids surface mineral makeup, using infrared readings of reflected sunlight.
"We have a fantastic data set because, to this point, the instrument has operated beautifully," said Cornell Universitys Joseph Veverka, who leads the multi-spectral imager/NIS team, in a statement.
Scientists hoped to continue using the instrument to map Eros southern hemisphere this fall, when it emerges from the gloom of space into the suns rays.
Now to do so, the science team will have to first correlate data collected from the northern hemisphere by the broken instrument with that gathered by two others, the multi-spectral imager and X-ray/gamma-ray spectrometers.
The team hopes to extrapolate from those results to figure out the mineral composition of the remainder of the asteroid. Eros surface is thought to be fairly uniform in its reflections of infrared light, Veverka said.
NEAR's data bounty includes this June 6 image of an 0.9-mile (1.4-kilometer) wide patch of the asteroid Eros.
NEAR Shoemaker -- recently renamed in honor of the late comet and asteroid expert Eugene Shoemaker -- is currently 85 million miles (136 million kilometers) from Earth. It orbits Eros at a scant 31 miles (50 kilometers), moving at a pokey 7 m.p.h. (11 kilometers per hour).
Next month, it will saddle up ever closer to Eros, coming within 22 miles (35 kilometers) of its grooved, boulder-strewn surface.
Robert Gold, the spacecrafts payload manager at Johns Hopkins, said the probes other instruments are operating extremely well. The $224 million mission concludes in February 2001.
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