| Gravity
Probe B is at NASA spacecraft processing hangar 1610 on
North Vandenberg Air Force Base. In processing activities
this week, the initial filling of the dewar with cryogenic
helium has been performed. This prepared the dewar for
the upcoming series of about 6 -7 cycles of pumping down
the tank to a near vacuum, then refilling as necessary,
to achieve the superfluid conditions. The first pump-down
began on Wednesday, Sept. 3.
The
electromagnetic interference (EMI) test and the Gas Management
Assembly (GMA) “rate of rise” test were successfully
finished as scheduled.
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. |
