WASHINGTON - The Pentagon has postponed decommissioning its experimental Orbital Express satellites until at least July 14 to give the U.S. military's senior leadership more time to consider extending the mission.

The two spacecraft that make up Orbital Express - the Boeing-built Autonomous Space Transport Robotic Operations (ASTRO) servicing spacecraft and the Ball Aerospace & Technologies-built NextSat - were launched together in early March on an Atlas 5 rocket. The in-orbit satellite servicing experiment was sponsored by the U.S. Defense Advanced Research Projects Agency, or DARPA.

Over the last four months, ASTRO twice has demonstrated its ability to approach NexSat with limited interaction from the ground, grapple the spacecraft with its robot arm and transfer fuel and hardware.

With no sponsors for an extended mission, the Pentagon had planned to begin decommissioning the satellites July 5 in a procedure that entailed separating the mated spacecraft, dumping their fuel, and turning them off. But that irreversible procedure is now on hold.

"We postponed our decommission again so it looks like we will kick off our de-mate this Thursday [July 12] which means we will likely not decommission it and turn off the vehicles until Monday or Tuesday," U.S. Air Force Lt. Col. Fred Kennedy, DARPA's Orbital Express program manager, told Space News in a July 10 interview. "This will give senior leadership one more opportunity to go back and determine do they really want us to turn them off or is there something else they want us to try."

Kennedy said DARPA Director Tony Tether asked the Orbital Express team to try one more maneuver that, if successful, would yield valuable additional data about the feasibility of on-orbit satellite servicing.

"What we would like to do is take the ASTRO vehicle all the way out to 300 kilometers and come back in for a rendezvous, but no capture, with NextSat," Kennedy said. "What that allows us to do is go out beyond our advertised sensor range," he said, referring to the ability of ASTRO's sensors to see and track NextSat.

Beginning July 12, ASTRO will separate from NextSat, drop back 300 kilometers over the next 12 hours and then, using location data from the U.S. ground-based Space Surveillance Network or some other source, try to find NextSat. Kennedy said the maneuver would be a more realistic demonstration of how an operational servicing satellite would have to function.

Tether had e-mailed more than 20 U.S. government officials June 29 - including Air Force Secretary Michael Wynne and Air Force Gen. Kevin Chilton, commander of Air Force Space Command - telling them Orbital Express would be turned off within a matter of days. Tether said in his e-mail that while it had been hoped that Orbital Express could be kept alive longer to support NASA test objectives, the Air Force rejected extending operations.

"It was hoped that OE would continue for NASA missions," Tether wrote. "However the Air Force is unable to support any further Orbital Express missions; rationale unknown at least to me but offers of paying the ground station cost for the next three weeks were rejected."

NASA spokesman Dwayne Brown said June 29 that the U.S. space agency opted not to pay for an Orbital Express extension, which would have been focused on demonstrating techniques useful to future Mars sample return missions.

Doug McCuistion, director of NASA's Mars Exploration Program, said July 9 that the agency was willing to pay the ground-operations cost of an extension, but was told that the Air Force needed the Orbital Express team to vacate its operations center at Kirtland Air Force Base, N.M., to make way for a "strategic activity."

McCuistion said July 9 NASA had wanted use of Orbital Express from mid July to September. During that time, he said, NASA intended to use ASTRO to capture the U.S. Naval Academy's MidStar-1 spacecraft. The tiny experimental satellite, located in a higher orbit, was more representative of a Mars soil-laden sample canister than NextSat, he said. NASA also wanted to try out some sample return-related algorithms that had been planned for the now-canceled 2009 Mars Telecommunications Orbiter.

Kennedy declined to comment on discussions between the Air Force and NASA but said he was not aware of any pressure on the Orbital Express team to clear out.

Kennedy also said that while NASA is not involved in current discussions about potential continued Orbital Express operations, the maneuver on tap for July 12 could yield data useful to the agency and its Mars sample return ambitions.

"It should still give NASA quite a bit of data to play with," he said.

As for the odds that Orbital Express will be kept in service beyond mid July, Kennedy would only say that "there's been some last-minute discussion among [Defense Department] decision makers on whether to keep this alive and if so why."

"If they decide there is something else they want us to do I'm sure they will communicate it to us," he said.