| Gravity
Probe B is at NASA spacecraft processing hangar 1610 on
North Vandenberg Air Force Base. In processing activities
this week, the electromagnetic interference (EMI) test
has been successfully completed. The Gas Management Assembly
(GMA) "rate of rise" testing is under way and
is successful to date with three days of the test remaining.
Certification testing of the pump module in preparation
for conditioning the dewar was successfully completed.
The dewar conditioning, a process of pumping down the
tank to near vacuum conditions, is currently under way.
Initial servicing to load the dewar 95 percent full of
cryogenic liquid helium is scheduled to begin next week.
The spacecraft is currently on internal power and a trickle
charge of the battery is occurring. Loading of an updated
version of the mission software is pending.
The
erection of the Boeing Delta II launch vehicle at Space
Launch Complex 2 remains scheduled to begin on Sept. 15
with the erection of the first stage. Attachment of the
nine strap-on solid rocket boosters in sets of three is
scheduled for Sept. 17-19. The second stage is planned
for mating atop the first stage on Sept. 22. Gravity Probe
B will be transported from the spacecraft hangar to Space
Launch Complex 2 on Oct. 29 and hoisted atop the second
stage. The Delta II fairing will be installed around the
spacecraft on Nov. 5 as part of final preparations for
launch.
Gravity
Probe B arrived at Vandenberg Air Force Base on July 11
from the Lockheed Martin plant in Sunnyvale, Calif.
Gravity
Probe B is a relativity experiment developed by NASA's
Marshall Space Flight Center, Stanford University and
Lockheed Martin. The spacecraft will test two extraordinary
predictions of Albert Einstein's general theory of relativity
that he advanced in 1916. Gravity Probe B consists of
four sophisticated gyroscopes to be launched into a 400-mile-high
orbit for a mission lasting 18 months. |
