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Gravity Probe B

Testing Einstein's Universe

WEEKLY HIGHLIGHTS FOR WEEK ENDING 31 OCTOBER 2003:



GRAVITY PROBE B LAUNCH STATUS

The GP-B spacecraft is scheduled to launch from Vandenberg Air Force Base in California on Saturday, December 6, 2003 at approximately 5:52 PM PST.



VANDENBERG AIR FORCE BASE OPERATIONS

The following activities were completed at VAFB this past week:
  • The first of four solar arrays was successfully installed on the Gravity Probe B space vehicle this week, and installation of the second solar array in in progress. Installing each solar array is a 3-day process. First the guard tank is filled with liquid helium. Then, the space vehicle is rotated and prepared for the installation. The solar ray is installed and a functional deployment test is performed. This process is repeated for each solar array.
  • Operations were completed on the Forward Equipment Enclosure (FEE). Metallic skins were attached, and then the FEE was enclosed with a multi-layer thermal insulation blanket, in preparation for launch.
  • The dewar was sealed two weeks ago at a temperature of 1.648 K. The temperature of the dewar is rising very slowly, but is expected to remain less than 1.88 K at launch time. The current temperature of the dewar is 1.695 K, which is well within the expected rate of rise.
  • All other space vehicle preparation activities at Vandenberg are proceeding on schedule, as planned.

Photos: The top image shows the first solar array in place on the Gravity Probe B space vehicle. The lower photo is a doctored close-up of the array installation. Click on the thumbnail of either photo to view view it full size.

MISSION CONFIRMATION TESTING REVIEW AT STANFORD

Regarding concerns about gyroscope readout performance, the Gravity Probe B team completed testing and review of the on-orbit electronics configurations to minimize measurement noise. An orbiting configuration which meets all of the Gravity Probe B objectives has been baselined. Test results were reviewed by NASA Headquarters and by an independent review team on Thursday this week, and Gravity Probe B was approved for the December 6, 2003 launch, pending a final closeout next week.


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