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

Figure 13-30. Correlation between Vertical PM Detector and Science Telescope (PYA).A more detailed analysis of the correlation will be done, taking into account the orientation of the telescopedetectors and the magnetic field, and possibly other factors that affect the proton flux through the spacecraft.13.2.6 Possible Post-Science Missions and AnalysisGP-B’s useful life does not end with the completion of the science mission. During the post-science phase of themission, we can carry out experiments utilizing the numerous onboard instruments and sensors.There are several possible experiments that would involve the proton monitor. For example, by changing theattitude and roll rate of the spacecraft, as well as the integration period of the proton monitor, we can effectivelycontrol the view angle and direction of both detectors, pointing them wherever the experiment commands.Using the data from the magnetometers, we can measure the proton flux at specific angles relative to themagnetic field lines. We can also combine the proton monitor data with the gyroscope charge measurements tostudy the contribution of high energy protons to gyroscope charge build-up. An ongoing effort that can andmost likely will be continued in the post-science phase is understanding how energetic protons contribute tomulti-bit errors (MBEs) that disrupt the onboard electronics.13.3 Payload MagnetometersAs described in 13.2.2 (“Proton Monitor Features and Specifications” ) of this report, a lead bag is used toattenuate the magnetic field around the Probe and gyroscopes within. In order to make an estimate on howstrong this field is after attenuation, it is helpful to have measurements of the original field around thespacecraft. This information is collected by four fluxgate magnetometers mounted around the cone of thedewar.Gravity Probe B — Post Flight Analysis • Final Report March 2007 375