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

Mitigating that risk during IOC became critical, and our solution to this problem was in several parts:• Implement software like TISI to do constraint checking among telemetry-critical tasks.• Direct sub-system engineer panel review on each and every load, every day• Flight Director and Mission Director oversight on each and every load, every day• Complete load presentation sessions at the end of the day, visually charting the timeline, contactschedule, and orbital geometry variables such as Guide Star visibility, South Atlantic Anomaly presence,Sun-Eclipse periods, and so forth• Rigorous version control of all load products, with hardcopy product sign-off of precisely the versionswhich would be sent to the spacecraftDuring the Science phase of the mission, daily workflow became much more streamlined, to the point where wewere able to have a baseline for each load during the week. This critical milestone allowed us to implement ourTCR (“Timeline Change Request”) process, which we’d specified prior to launch. Using this systemimmediately resulted in a number of benefits:• Web-based design: use anywhere, cut-and-paste from other electronic products eliminatestypographical errors• First-hand input: written directly by sub-system engineers• Approval from managers: all TCRs must be approved by a Mission Director• Peer review among all other sub-system engineers: eliminates unanticipated impacts in other subsystems• Post-implementation review during load sign-off to assure that each and every off-baseline change wasas-intendedThese safeguards proved to be very effective during both the IOC and Science phases of the mission. Timelinesgenerated by the Mission Planning team never created a spacecraft emergency and never put the spacecraft in adegraded state.In summary, the Mission Planning team was able to consistently deliver high quality products that:• Met engineering specifications,• Were thoroughly cross-checked for accuracy by software and a panel of engineers• Were generated with increasing rapidity as the mission progressed• Were available to our user community anywhere they might have been.Mission accomplished!4.3 Data Processing4.3.1 GeneralData processing greatly surpassed its nominal requirement of 95% data capture. The Data Processing teamsupported all vehicle operations and retrieved data in challenging situations, sleuthing out any additional dataconcerns. Data processing team members are currently addressing the task of archiving GP-B data for longtermaccess.Gravity Probe B — Post Flight Analysis • Final Report March 2007 107