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

The GP-B spacecraft was a total system, comprising both the space vehicle and its unique payload—anintegrated system dedicated as a single entity to making the measurements of unprecedented precision (eightorders of magnitude more accurate than the best navigational gyroscopes) required by the experiment. Toaccomplish this goal, it was necessary for the total, tightly-integrated system to be developed by a strong andcohesive team. This chapter provides an overview of some of the important issues, challenges, trade-offs andpractices that were involved in managing GP-B over a period of more than four decades to a successfulperformance of its mission.6.1 The Phases of GP-B Program ManagementNASA generally divides programs into six phases:• Phase A-Preliminary Analysis• Phase B-Definition• Phase C-Design• Phase D-Fabrication, Assembly and Testing• Phase E-Mission Operations• Phase F-Data Analysis & Results DeterminationTo some degree, all NASA programs progress through these phases. However, often-and especially in the caseof GP-B, NASA's oldest continuous research program, whose origins date back NASA's infancy—there is muchoverlap between phases, and it is difficult to assign these phase labels to distinct chronological periods. Instead,it is more useful to describe GP-B's development and program management in terms of the following five maintime periods:1. The Early Years (1959-1984). During this period, the relativity gyroscope experiment was conceived atStanford and became a NASA-funded, university research program. The relativity gyroscope experimentevolved into a NASA mission, and was given the name “Gravity Probe B.”2. Flight Hardware Development (1984-1997). For reasons described in this section, NASA madeStanford its prime contractor in 1984, with NASA Marshall Space Flight Center provided the program’snominal oversight. This decision was dubbed “the GP-B Management Experiment” by James Beggs, theNASA Administrator at that time. Following a rigorous selection process, Stanford contracted withLockheed Missiles and Space Corporation (LMSC, now Lockheed Martin Space Systems Company orLMSSC 1 ) as principal subcontractor for constructing the integrated payload (dewar and probe). In alater, separate selection process, Stanford also selected LMMS for constructing the spacecraft. Towardsthe end of this period, GP-B made the challenging transition from maximizing research and technologydevelopment advances to minimizing risk as the payload and spacecraft were readied for launch.1.The aerospace division of Lockheed Martin Corporation has undergone a number of name changes over thelife of GP-B. In 1984, when Stanford first contracted with the company to build the GP-B dewar and probe,it was then called Lockheed Missiles and Space Company (LMSC). In 1995, the parent Lockheed Corporationmerged with the Martin Marietta Corporation to become the Lockheed Martin Corporation, and the aerospacedivision became Lockheed Martin Missiles and Space (LMMS). A few years later, the Lockheedaerospace division underwent yet another name change to the current Lockheed Martin Space Systems Company(LMSSC). Throughout the development of the dewar, probe and other payload systems, GP-B subcontractedwith the Lockheed Palo Alto Research Lab (LPARL), located next to Stanford. The spacecraftfabrication and assembly was carried out at the company’s nearby Sunnyvale, CA facility. For the sake ofsimplicity, we have chosen to use “Lockheed Martin,” or the acronym “LM” for all further references toLockheed Martin Space Systems Company in this chapter.Gravity Probe B — Post Flight Analysis • Final Report March 2007 141