is unsuccessful in '89, it will be back in '90, and that will get in the way of CRAF/Cassini.
The thermal vacuum test was run with the 39-foot tall AXAF placed in a large sealed chamber that was pumped down to simulate the vacuum of space.
Since the AXAF instruments are designed to operate in a vacuum, this thermal vacuum test is the last time prior to launch when its key functions can be tested in a realistic environment.
The AXAF thermal vacuum testing process also provided opportunities for the operators of the AXAF Operations Control Center (OCC) in Cambridge, Mass.
According to Craig Staresinich, TRW's AXAF program manager, the testing process proved invaluable because the AXAF team uncovered a mechanical problem with one of the observatory's science instruments, the AXAF CCD Imaging Spectrometer (ACIS).
The AXAF High Resolution Mirror Assembly (HRMA), the optical heart of NASA's third Great Observatory, was delivered on May 6 to TRW's Space Park satellite integration facilities in Redondo Beach.
AXAF is scheduled to be launched from the Space Shuttle in August 1998.
We are delighted with the timely completion of the HRMA's X-ray testing and its delivery to TRW," said Ed Wheeler, TRW's AXAF program manager.
At that time, it will be mated with the AXAF spacecraft bus, which TRW is currently integrating and testing.
TRW Space & Electronics Group is building AXAF for NASA's Marshall Space Flight Center, Huntsville, Ala.
TRW expects to begin assembling and testing the AXAF spacecraft during spring 1997, with integration of the spacecraft with its X-ray telescope and science instruments slated to begin in the fall of 1997.
The mirrors must be precisely aligned to focus X-rays from celestial sources onto science instruments located at the other end of the AXAF telescope.