NEAR Shoemaker trained its camera on Eros' large, 5.3-kilometer (3.3-mile) diameter crater for a series of color pictures intended to measure the properties of regolith inside the asteroid's craters. In this false color view -- taken from an altitude of 50 kilometers (31 miles) -- redder hues represent rock and regolith that have been altered chemically by exposure to the solar wind and small impacts. Bluer hues represent fresher, less-altered rock and regolith, such as the bright patches that have been less affected by "space weathering." In that process, during micrometeorite impacts, rock reacts with miniscule amounts of trapped solar wind and is chemically changed. Interestingly, most of the large boulders have been just as affected as the regolith. This suggests either that the rocks are relatively old, or that they are "dirty" from an adhering film of regolith particles. Photo: JHU/APL

A burst from its thrusters on Friday sent NEAR Shoemaker on a weeklong descent toward its closest look yet at asteroid Eros.

At 2 p.m. EDT (1800 GMT), the spacecraft flawlessly performed a 20-second engine burn on commands from the NEAR Mission Operations Center at the Applied Physics Laboratory.

The first orbit correction maneuver since April 30 nudged NEAR Shoemaker from 31 miles (50 kilometers) above Eros toward lower vantage points 22 miles (35 kilometers) from the asteroid's center and -- at times -- less than 12 miles (19 kilometers) from its ends.

Flying around a peanut-shaped space rock is still a tricky business, but the risks lessen as NEAR Shoemaker's navigators learn more about Eros' size, shape and rotation. "Now that we have a better read on the asteroid, our ability to predict where we're going is much better than it was earlier in the mission," says Bobby Williams, who heads the NEAR navigation team at NASA's Jet Propulsion Laboratory.

Once NEAR Shoemaker reaches the 22-mile orbit on July 14, the NEAR team will spend four days reassessing the asteroid's gravity field. The 10-day orbit also includes plans to take high-resolution images of the surface, refine estimates of the asteroid's mass and density, gather additional data on the asteroid's elements and continue searching for a magnetic field.