— NASA’s Lunar Reconnaissance Orbiter (LRO) will not launch before April 24 “due to circumstances beyond NASA’s control,” according to a spokeswoman for the NASA field center building the spacecraft.

NASA officials say the $600 million spacecraft could be ready to launch before the end of 2008 – the goal U.S. President George W. Bush set for the mission more than four-and-a-half years ago when he announced the Vision for Space Exploration – but competing demand for launch services from Cape Canaveral, Fla., in the months ahead initially prompted LRO to shift to a February launch opportunity. Launch manifests at the
and Vandenberg Air Force Base in
have been further scrambled by an industry-wide components-alert that is slowing the launch rate of Atlas and Delta rockets.

Craig Tooley, the LRO program manager at NASA’s
, said in an Oct. 21 e-mail that LRO officially has been remanifested for a launch window that opens April 24. Tooley said the delay was “based on launch vehicle manifest considerations and not LRO readiness.”

Goddard spokeswoman Nancy Jones said in a follow-up to Tooley’s e-mail that NASA signed a contract modification with United Launch Alliance Oct. 14 formalizing the changed launch date. Jones said postponing the launch until April would not negatively impact NASA’s plans for returning humans to the Moon by 2020.

NASA awarded the LRO launch contract prior to the establishment of United Launch Alliance. The original contract awarded in July 2006 to Lockheed Martin was worth $136.2 million. United Launch Alliance spokeswoman Julie Andrews did not have an updated contract value when contacted Oct. 22.

The LRO spacecraft, which is designed to make a detailed map of the Moon’s surface during its nominal one-year mission, successfully completed electromagnetic interference testing at Goddard in September. On Oct.16, according to a NASA mission update, the spacecraft was moved into a thermal vacuum chamber to undergo the last of its environmental tests.

Tagging along to the Moon with LRO is a roughly $80 million companion spacecraft called the Lunar Crater Observation and Sensing Satellite, or LCROSS. Its mission is to send back pictures of the Atlas 5 rocket’s spent Centaur upper stage crashing into the lunar surface. LCROSS is being built by NASA’s
Moffett Field
, and Northrop Grumman Space Technology of Redondo Beach, Calif.

Northrop Grumman spokeswoman Sally Koris said Oct. 22 that LCROSS has completed all environmental testing and is in storage awaiting orders from NASA to ship it to
Cape Canaveral