Gravity Probe-B Launch Status Report 1 Oct 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 in NASA spacecraft processing hangar 1610 on North Vandenberg Air Force Base. The spacecraft and mission team have successfully completed a four-day mission simulation.

  Conditioning of the dewar to a superfluid state has been completed.  Conditioning is the process of taking liquid helium at a temperature of about 4 Kelvin (-452 degrees F) to a colder state, known as superfluid, which will allow the helium to last throughout the duration of the mission.  Filling the dewar with superfluid helium is a slow and repetitive process.   The dewar is now 95% full of superfluid helium at a temperature of 1.65 Kelvin (-456 degrees F), and it will be maintained in this state from now until launch.

In upcoming spacecraft activities, electrical testing is scheduled for Oct. 8, ordnance installation is scheduled for Oct. 20-24, and solar array installation is scheduled to begin Oct. 27.

The first stage of the Boeing Delta II was erected on Space Launch Complex 2 on Monday, Sept. 15, as scheduled.  Mating of the second stage atop the first stage also occurred as planned on Sept. 18.

The attachment of the nine strap-on solid rocket boosters in sets of three is scheduled for Oct. 6-8.  Integrated testing of the vehicle will begin on Oct. 14.  This will be followed on Oct. 29 by guidance and control system checks.  An exercise that involves loading of liquid oxygen aboard the first stage and a limited “minus count” will be conducted on Nov. 4.  A Simulated Flight test, a “plus count” that tests the launch vehicle systems as if it were in powered flight, will be performed on the following day, Nov. 5.