The XSS-10 is the service’s first work in space involving microsatellites that can autonomously approach other objects in space, said Thom Davis, program manager for the experiment at the Air Force Research Laboratory’s Space Vehicles Directorate, Albuquerque, N.M. The laboratory built the satellite, which weighed 28 kilograms, for $100 million.

The experiment was also the first in which the service activated satellites hours after launch, Davis said. Satellites generally require an on-orbit checkout that spans weeks or months.

Pentagon officials have expressed interest for years in small satellites that could maneuver in space to refuel and repair U.S. spacecraft or assess possible threats in orbit. Senior Defense Department officials told reporters during a recent budget briefing that the Air Force plans to begin work in 2004 to develop other satellites that can be activated quickly once they reach orbit.

XSS-10 rode to orbit Jan. 29 as a secondary payload to a Global Positioning System navigation satellite aboard a Delta 2 rocket. Shortly after reaching space, the XSS-10 spacecraft maneuvered about 200 meters away from the rocket, and then approached it, taking video imagery that was transmitted live to officials on the ground, Davis said.

Data from the XSS-10 experiment will feed into future work that the military does in this area, including the XSS-11, which is expected to conduct a similar mission over a longer duration in 2004, and Orbital Express, which is slated to demonstrate the refueling of a satellite in space in 2006, Davis said. Davis said he looks forward to more complex demonstrations that will involve spacecraft maneuvering over longer distances to approach other satellites.