Asteroid Eros. Photo: JHU/APL

A short engine burn on April 22 started NEAR Shoemaker on a gradual journey toward its ideal scientific orbit around asteroid Eros. At 1:50 p.m. Eastern Daylight Time, the spacecraft fired its breaking thrusters and moved down from the 62-mile (100-kilometer) orbit it occupied for the previous 11 days.

The burn -- which occurred with the spacecraft about 119 million miles (190 million kilometers) from Earth -- was the fifth "orbit correction maneuver" for NEAR Shoemaker since it encountered Eros on Feb. 14. On April 30, NEAR Shoemaker will begin a circular orbit 31 miles (50 kilometers) from Eros' center. Though all six of the spacecraft's scientific instruments have been turned on for several weeks, this is the distance from which two of those devices -- the Laser Rangefinder and X-Ray Gamma Ray Spectrometer -- are designed to work best. The performance of the other instruments also improves as NEAR Shoemaker moves in for closer looks at the 21-mile-long rotating space rock.

Built and managed by The Johns Hopkins University Applied Physics Laboratory, Laurel, Maryland, NEAR-Shoemaker was the first spacecraft launched in NASA's Discovery Program of low-cost, small-scale planetary missions.