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

Figure 14-9. In the Anomaly Room, team members discuss a series of recovery commands thatwill be uploaded to the spacecraft. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 407Figure 14-10. British Astronomer Royal, James Bradley . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 409Figure 14-11. Due to the motion of the Earth, the apparent position of a distant star viewed through a telescopediffers from its actual position—Bradley called this difference the aberration angle. . . . . . . . . . . . 411Figure 14-12. GP-B's Orbital aberration of light from the Guide Star, IM Pegasi . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 412Figure 14-13. GP-B's annual aberration of light from the Guide Star, IM Pegasi . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 413Figure 14-14. Schematic diagram of the GP-B telescope optics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 414Figure 14-15. Normalized pointing values for the GP-B telescope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 415Figure 14-16. Centering the telescope's light distribution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 415Figure 14-17. The telescope dither pattern around Guide Star, IM Pegasi . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 416Figure 14-18. Components of the GP-B Data Analysis Standard Model (equations shown are significantlysimplified and are of iconic value only) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 421Figure 15-1. A photo montage of the GP-B spacecraft in orbit and a photo of the GP-B Mission Operations Centerin action during the spin-up of gyro #4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 425Figure 15-2. A diagram of the GP-B experiment showing the predicted geodetic and frame-dragging effects. . .426Figure 15-3. A slide from the GP-B plenary talk that Francis Everitt will deliver at the APS meeting on April 14,2007. The plots on the left side of this slide clearly show the predicted geodetic effect in theunprocessed gyro data to an accuracy level of ~1%. A copy of this talk will be available on the APSpage of the GP-B Web site:http://einstein.stanford.edu/content/aps_posters#talks. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 426Figure 15-4. A slide from the GP-B plenary talk that Francis Everitt will deliver at the APS meeting on April 14,2007. This slide shows the changing polhode paths of gyros #1 and #4 and summarizes the issues ofpolhode rate variations in the gyros. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 428Figure 15-5. A slide from the GP-B plenary talk that Francis Everitt will deliver at the APS meeting on April 14,2007. This slide shows the misalignment torques discovered during a series of instrumentcalibration tests performed during the last six weeks of the mission, prior to depletion of helium inthe dewar. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 429Figure 15-6. Plots from different viewing angles showing the changing polhode path of gyor #1 over the life ofthe experiment. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 430Figure 15-7. A poster on gyro polhode motion to be presented at the APS meeting in April 2007.You can view/download a larger and more readable PDF version of this posteron our GP-B APS Web page: http://einstein.stanford.edu/content/aps_posters#posters. . . . . . . . 431Figure 15-8. A slide from the GP-B plenary talk that Francis Everitt will deliver at the APS meeting on April 14,2007. This slide shows how dither and aberration of starlight are used as calibrating signals indetermining the gyro-telescope scale factor, C g . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 432Figure 15-9. A poster on the effects of classical torques on the gyros to be presented at the APS meeting in April2007. You can view/download a larger and more readable PDF version of this posteron our GP-B APS Web page: http://einstein.stanford.edu/content/aps_posters#posters. . . . . . . . 434Figure 15-10. A poster on the evidence for patch effects to be presented at the APS meeting in April 2007.You can view/download a larger and more readable PDF version of this poster on our GP-B APS Webpage:http://einstein.stanford.edu/content/aps_posters#posters. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 435Figure 15-11. A slide from the GP-B plenary talk that Francis Everitt will deliver at the APS meeting on April 14,2007. This slide shows the succession of investigative steps and observations that led to thedetermination that patch effects are the root cause of both the polhode variation and misalignmenttorques on the gyros. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 436Figure 15-12. A slide from the GP-B plenary talk that Francis Everitt will deliver at the APS meeting on April 14,2007. This slide shows the GP-B data analysis team, except for Principal Investigator, Francis Everitt.A copy of this talk will be available on our APS Web site:http://einstein.stanford.edu/content/aps_posters#talks. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 437xxii March 2007