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

NASA Headquarters. Roman was quite influential in creating astronomical research satellites such as theOrbiting Space Observatory (OSO), the Cosmic Background Explorer (COBE) and the Hubble Space Telescope(HST). In July 1961, under Roman’s direction, NASA sponsored a conference at Stanford on the topic ofexperimental tests of general relativity. This conference, which was attended by many of the leading relativisticphysicists and aerospace engineers of the day, helped crystallize various issues that needed to be addressed inorder to carry out the relativity gyroscope experiment.One important result of that conference was the idea of developing a “drag-free” satellite—a satellite that couldorbit the Earth exactly as if acted upon by gravity alone—not by solar pressure or atmospheric drag. This featurewas critical to the relativity gyroscope experiment because the effects of orbital drag on the gyroscopes wouldobscure the minuscule relativistic effects being measured. At the conference, Benjamin Lange, a Stanford Aero-Astro graduate student (and later a professor in the Stanford Aero-Astro Department) had an “aha moment,” inwhich he figured out how to create a “drag-free” satellite. This became the topic of his doctoral dissertation andseveral other dissertations to follow in the Stanford Aero-Astro department, under the supervision of ProfessorRobert Cannon.Meanwhile, William Fairbank and his graduate students had begun investigating various cryogenic topicsrelated to gyroscope composition, as well as gyro suspension, readout, and spin-up systems. In 1962, Fairbankinvited Francis Everitt to come to Stanford as the experiment's first full-time academic staff member. Workingwith Fairbank, Everitt proposed using the London Moment property of spinning superconductors as the basisof a gyroscope readout system, and he helped redefine several other aspects of the experiment, such as theelectrostatic gyro suspension system.During the years 1963-1967, GP-B grew slowly as a university research program, with William Fairbank andRobert Cannon each managing research teams in their respective departments. Late in 1963, Stanford submitteda proposal to NASA entitled: Proposal To Develop a Zero-G Drag Free Satellite and Perform a Gyro Test of General Relativity ina Satellite. In March 1964, NASA's Office of Space Science funded this proposal in the amount of $180,000, withRoman serving as NASA Program Manager. The proposal named William Fairbank and Robert Cannon as Co-Principal Investigators, with Leonard Schiff as Project Advisor. Once funded, the research program began toexpand rapidly. Pictured in Figure 6-1below are GP-B co-founders Leonard Schiff, William Fairbank, RobertCannon, and Nancy Roman, former Chief of Astronomy and Relativity Programs in the NASA Office of SpaceSciences.Gravity Probe B — Post Flight Analysis • Final Report March 2007 143