January 26, 1999

Chandra X-ray Observatory Status Report

Dave Drachlis, Marshall Space Flight Center, Huntsville, AL (Phone: 205/544-0034)

The NASA/contractor team developing the Chandra X-ray Observatory continues to make progress this week in evaluating and correcting the recently discovered potential problem with several printed circuit boards in the observatory's command and data management system.

TRW Space and Electronics Group, Redondo Beach, CA, removed the observatory's command and telemetry unit from the spacecraft last week and shipped it to BF Goodrich Aerospace, Davis Systems Division in Albuquerque, NM, on Friday. The unit is in the process of being disassembled to remove and replace two suspect circuit boards.

Meanwhile testing to determine if other circuit boards in the observatory's five remote command and telemetry units will require replacement is ongoing at TRW. Managers have decided to extend that testing by one week to add more confidence in the results.

The extension will subject the printed circuit board test articles to the rigors of on-orbit operations equal to three times (instead of twice) the observatory's planned lifetime. "This will provide added confidence in our results and still allow us to meet our adjusted shipping date if the results indicate we do not have to replace additional boards," explained Fred Wojtalik, Chandra Program Manager at NASA's Marshall Space Flight Center in Huntsville, AL. "We now anticipate wrapping up the test next weekend (Jan. 30/31) and having initial results by early the following week," said Wojtalik.

Meanwhile, technicians at TRW this week began preparing the observatory for shipment to the Kennedy Space Center in Florida, pending the outcome of the testing. Double bagging of the spacecraft to protect it from contamination during shipment got underway last night.

TRW, NASA's prime contractor for the observatory, discovered the potential problem with the printed circuit boards during recent testing of another spacecraft. The problem was traced to poor conductivity between different layers of the boards. Similar boards are used in Chandra's main command and telemetry unit and five remote units. These units provide command and data communications links between the observatory's computer and subsystems.

Dave Drachlis, MSFC Media Relations Office