Chandra X-ray Observatory

Tuesday, April 27, 1999

Dave Drachlis
Media Relations Office
NASA Marshall Space Flight Center
(256) 544-6538

NASA decided yesterday to postpone mating the Chandra X-ray Observatory with its Inertial Upper Stage (IUS), pending additional progress in the U.S. Air Force investigation into problems with the April 9 launch of a Department of Defense satellite.

NASA had planned to move the IUS from its processing facility at Cape Canaveral Air Force Station, Fla., to the Vertical Processing Facility at the Kennedy Space Center, Fla., this week and attach the upper stage to the Chandra observatory at the end of the month. The upper stage instead will temporarily remain in its processing facility.

While the decision will delay Chandra's launch beyond July 9, the specific impact on Chandra's launch date is not yet known. NASA is participating with the Air Force in the investigation and will not launch Chandra on Space Shuttle mission STS-93 until the situation is fully understood.

"Chandra is the world's most powerful x-ray telescope and a vital international scientific resource," said Fred Wojtalik, Chandra program manager at NASA's Marshall Space Flight Center in Huntsville, Ala. "While we will do all we can to launch Chandra as soon as appropriate, we are going to take all the time that is necessary to ensure that when we do launch Chandra it will successfully perform its important mission."

"The observatory itself is in great shape, is checking out well, and processing for launch has been going very smoothly," said Wojtalik.

Chandra had been undergoing preparation for a July 9 launch aboard the Space Shuttle Columbia in the Vertical Processing Facility since its arrival at the Kennedy Space Center on Feb 4.

Loading of nitrogen tetroxide and hydrazine propellants for Chandra's own integral propulsion system was completed on April 15. Hydrazine used by one of the subsystems that will point the telescope in space is scheduled to be loaded Wednesday or Thursday. To make best use of the time, NASA plans to proceed with some pre-launch testing of the observatory in parallel with the investigation.

The IUS is a two-stage solid rocket that will be used to help propel the Chandra observatory from low earth orbit to its operating altitude nearly a third of the way to the moon.