For Release: Jan. 20, 1999

NASA today announced that it will delay this month's planned shipment of its Chandra X-ray Observatory from prime contractor TRW Space and Electronics Group, Redondo Beach, CA, to NASA's Kennedy Space Center , Fla. The postponement will allow TRW to evaluate and correct a potential problem with several printed circuit boards in the observatory's command and data management system.

TRW notified NASA of the potential problem last week after another spacecraft being built by the company experienced a failure during testing that was attributed to similar printed circuit boards. The failed boards and those in Chandra were all made by BF Goodrich Aerospace, Davis Systems Div., Albuquerque, NM, in the same time frame in 1996. The problem has been traced to poor conductivity between different layers of the boards.

The boards are used in Chandra's main command and telemetry unit and four remote units. These units provide command and data communications links between the observatory's computer and subsystems.

NASA has directed TRW to remove and replace the boards in the main unit, and to conduct further tests and evaluation to determine if it is also necessary to replace the boards in the remote units. The repair, if limited to boards in the main command and telemetry unit, is expected to delay shipment to Kennedy by approximately one week. This will result in approximately a five-week slip in the observatory's launch readiness date, which will allow for integration and testing of the units at Kennedy. If boards in the remote units must also be replaced, a more extensive slip is anticipated.

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