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Eros Light Curve This graph shows variations in brightness of the asteroid Eros over one rotation period, that is, one asteroid "day." The measurements were taken over a period of 5.9 hours on January 12-13, 2000 by the multispectral imager on the Near Earth Asteroid Rendezvous (NEAR) spacecraft. At that time NEAR was 27,000 miles (45,250 km) from Eros, and was approaching the asteroid at a velocity of 43 miles per hour (19 meters per second). NEAR was 170 million miles (274 million kilometers) from Earth. Eros is a very elongated object about 21 by 8 by 8 miles (33 by 13 by 13 kilometers) in size. On the graph, the longitude corresponds to the sub-spacecraft point on the asteroid. The variations in brightness are caused by differences in the fraction of Eros viewed from the spacecraft as the asteroid rotates.
During the next month NEAR will continue to approach Eros at a low velocity, and the asteroid will appear progressively larger in images returned from the spacecraft. On February 14 NEAR will fire its thrusters and begin to orbit Eros, becoming the first artificial satellite of any asteroid.
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Built and managed by The Johns Hopkins University Applied Physics Laboratory, Laurel, Maryland, NEAR was the first spacecraft launched in NASA's Discovery Program of low-cost, small-scale planetary missions. See the NEAR web page at http://near.jhuapl.edu for more details. Feedback to Scott Murchie. Scott.Murchie@jhuapl.edu.