NASA Spacecraft and Expendable Vehicles Status RPeort 10 Sep 2003
MISSION:Gravity Probe B (GP-B)
LAUNCH VEHICLE:Delta II
LAUNCH PAD: SLC-2, Vandenberg Air Force Base
LAUNCH DATE: December 6, 2003
LAUNCH TIME:5:52:02 p.m. PST
Gravity Probe B is at NASA spacecraft processing hangar 1610 on North Vandenberg Air Force Base. The pumping down of the dewar which is filled with cryogenic helium is continuing this week. This brings the environment within the dewar to a near vacuum. It will then be refilled to the level necessary to achieve and maintain superfluid conditions.
Preparations are beginning for the planned erection next week of the Delta II launch vehicle at Space Launch Complex 2. Due to some observed delaminations within the layers of material that comprise the solid rocket booster nozzle exit-cone liners, some additional time is necessary to perform a precautionary change out of three of the nine boosters assigned for this mission. The additional time required means that the launch is being rescheduled for Saturday, Dec. 6.
The start of erection activities of the Boeing Delta II remains scheduled to begin on Sept. 15 with the erection of the first stage. The second stage is now planned for mating atop the first stage on Sept. 18. Attachment of the nine strap-on solid rocket boosters in sets of three is scheduled for Oct. 6-8.
Gravity Probe B will be transported from the spacecraft hangar to Space Launch Complex 2 on Nov. 18 and hoisted atop the second stage. The Delta II fairing will be installed around the spacecraft on Nov. 24 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.
