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Gravity Probe B

Testing Einstein's Universe

WEEKLY HIGHLIGHTS FOR WEEK ENDING 9 JANUARY 2004:


GRAVITY PROBE B LAUNCH DATE

We currently anticipate that the Gravity Probe B space vehicle will launch from Vandenberg Air Force Base in Southern California sometime in the 2nd Quarter of 2004. Although not yet confirmed, April 20, 2004 appears to be the earliest launch date. The exact time of launch depends on the date. On April 20th, the launch would be around10:00 AM Pacific Daylight Time and about 4 minutes earlier each day thereafter.

We update these highlights every Friday, and we will post any new information about the launch as soon as it becomes available. Please bookmark this Web site and check back often for the latest GP-B launch infromation.

VANDENBERG AIR FORCE BASE OPERATIONS THIS WEEK

Following is the current status of the GP-B spacecraft and launch vehicle at VAFB:
  • The Gravity Probe B spacecraft is being maintained in a stand-down state, awaiting the return of the reworked Experiment Control Unit (ECU).
  • The temperature of the dewar's main tank is 1.8580 K. The guard tank was re-filled to a level of 85.4%. The heat rate is 23.2 mW.
  • The battery charge is being monitored continuously during the stand-down period.
  • The Delta II launch vehicle, with the solid motors attached, will remain on the launch pad, surrounded by the mobile service tower (MST), for the duration of the repair period.
  • After thorough inspections, it has been determined that the 6.5 magnitude earthquake, centered 70 miles North of VAFB on December 22, 2003, caused no damage to the GP-B spacecraft. Analex/NASA reported that Boeing reported some minor damage to the Delta II booster, due to it rubbing against some bumpers during the quake. Also, some seals were broken on rack doors inside the Electronics Equipment Bldg. All damaged areas have been fixed or replaced on the Launch Vehicle, Mobile Service Tower, and Electronic Equipment Building. The bumpers (which are placed on the Mobile Service Tower for earthquake protection) performed as designed and allowed only minor damage to occur.

 

LOCKHEED MARTIN, PALO ALTO OPERATIONS THIS WEEK

  • The re-designed ECU power bracket and filter board successfully passed synchronization signal checks. Synchronization signal quality at the converters was excellent, and ECU input voltage sweeps showed no oscillations on either the A or B sides of the ECU.
  • Ambient testing was completed on the ECU, and preliminary data analysis showed line regulation to be within specification on all converters, with low output noise spectrum levels.
  • The ECU is currently undergoing thermal vacuum testing, and an ECU Readiness Review is scheduled early next week.

Photos: In the upper photo, Lockheed Martin photographer Russ Underwood captured the Gravity Probe B spacecraft on November 10, 2003 (Press Day) from a high perch in the vehicle processing room. Assuming that the reworking and testing of the ECU continues on schedule, the spacecraft will be returned to this launch-ready state by March, 2004. The lower photo shows the ECU (black box), which was removed from the spacecraft, on a test bench at Lockheed Martin in Palo Alto, CA. Click on the thumbnails to view enlargements of the photos.

GRAVITY PROBE B ON THE NATIONAL CBS EVENING NEWS, SUNDAY, DECEMBER 28, 2003

On Sunday evening, December 28, 2003, the Cover story on the CBS Evening News was on the subject of time—examined from both human and cosmic perspectives. The story featured interviews with a manager from Torneau Time Machines (the largest watch store in New York City), physicist Brian Greene (a proponent of String Theory), and our own Gravity Probe B Principal Investigator, Francis Everitt. Typical of television news, the entire story lasted a little over three minutes, but it was heart warming to see Francis and our spacecraft on the national news. Perhaps the best sound byte from Francis was a quote from St. Augustine that CBS chose not to use: "What was God doing before he made heaven and earth? ... He was preparing hell for those that would pry into such profound mysteries."

Click here to view a video clip of the CBS News story about time.

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