GP-B Post-Flight Analysis—Final Report - Gravity Probe B - Stanford ...

16 April 2004—Vehicle is Prepared for April 19LaunchInstallation of the payload fairing—the “nose cone” at the top of thelaunch vehicle that surrounds and protects the spacecraft duringlaunch has been completed. Four minutes and 41 seconds after launch,the fairing will split apart and be jettisoned into space, in preparationfor the second stage rocket to position the spacecraft in its circularpolar orbit and proper orientation towards the guide star, IM Pegasi.The launch vehicle, with its payload and fairing at the top, are stillsurrounded by the Mobile Service Tower (MST). Very early Mondaymorning, the MST will be rolled away, leaving the launch vehiclestanding in readiness as the launch countdown begins.Yesterday, the temperature of the dewar's main tank was 1.797K, andthe dewar was 95.5% full. The Guard Tank level was 76.6%.A Flight Readiness Review (FRR) was successfully conductedyesterday, and Gravity Probe B is “Go” for launch.Today, Gravity Probe B Co-Principal Investigator, John Turneaure,was interviewed by Ira Flatow on NPR Talk of the Nation—ScienceFriday. This Sunday evening, April 18th, a feature story about GravityProbe B and principal investigator, Francis Everitt, is scheduled to airon ABC World News Tonight.C.2 GP-B Launch: 4/19/04 – 4/20/0419 APRIL 2004—GRAVITY PROBE B LAUNCHPOSTPONED FOR 24 HOURSA launch hold was called three minutes before the scheduled liftoff ofthe Gravity Probe B spacecraft. Marginal upper level wind conditionshad been observed throughout the countdown, and there wasinsufficient time to confirm that the Delta II rocket had the correctwind profile loaded for the data from the final weather balloon. Thelaunch of Gravity Probe B has been re-scheduled for tomorrow(Tuesday), April 20, 2004 at 9:57 AM Pacific Daylight Time, fromVandenberg Air Force Base in South-central California. The GP-Bsatellite has only a one-second launch window. Why a one-secondlaunch window? Find out on our FAQ Page.Following the launch on the Internet: The launch was Webcast onNASA Direct, as well as on NASA TV on the Web. To view NASADirect, see http://www.ksc.nasa.gov/nasadirect/index.htm. Forinformation about viewing NASA TV on the Web, using either theReal Player or Windows Media Player, seehttp://www.nasa.gov/multimedia/nasatv/index.html. You'll find a listof alternate sources of NASA TV on the Web athttp://www.nasa.gov/multimedia/nasatv/MM_NTV_Web.html.Another very comprehensive source of information is the SpaceflightNow Web site:http://www.spaceflightnow.com/delta/d304/status.html.We will send out more updates as new information becomes available.20 APRIL 2004—GRAVITY PROBE B LAUNCHEDSUCCESSFULLY TODAY AT 9:57:24 AM PDT!At 9:57:24 AM PDT today, the Gravity Probe B spacecraft wassuccessfully launched from Vandenberg Air Force Base in SouthcentralCalifornia. The countdown went smoothly, and at the momentof launch, a packed auditorium here at Stanford University broke intocheers and applause.The launch is proceeding perfectly, exceeding all of our expectations.The initial visual images from the various tracking stations were heartwarmingand beautiful to behold—surpassed perhaps only by theextraordinary images from the two cameras on-board the secondstage, which showed the separation of the spacecraft from the launchvehicle more than 300 miles above the Earth.472 March 2007 Appendix C — Weekly Chronicle of the GP-B Mission