Effective Use and Assessment of GSFC On-orbit Heritage
for Greater Mission Success
Hsu, Feng; Warren, Connley
ABSTRACT It has been a major challenge within NASA for project managers and mission system engineers to make adequate decisions regarding spacecraft design configurations and reliability margins based on trade-offs that merely considering the design-based mission success predictions. In order to address this technical challenges and help MMS project management to make better technical and programmatic decisions, a so-called Goddard mission success study has been initiated by GSFC CMC (Center Management Council) and conducted by S&MA directorate to investigate the uncertainties regarding the design reliability predictions as opposed to the actual spacecraft mission performances during the on-orbit flight operations. Some statistical techniques combined with Bayesian methodology is employed to analyzing the use of redundancy as opposed to use of single-string configuration in reliability design and mission risk trade-offs. In lieu of the uncertainties exist between the predicted mission success likelihood and the actual spacecraft performance during on-orbit phase of a space mission, this paper presents the outcomes of a focused study carried out by GSFC S&MA to review spacecraft component on-orbit failure rates over the last 10 years including factors such as parts requirements, redundancy and implementation mode to support risk-based decisions on mission assurance approach for multiple-spacecraft project constellations such as MMS. The evaluation was performed in attempting to draw conclusions for single string spacecraft, single string spacecraft with upgraded parts and single string spacecraft with selective redundancy. A broad range of data information has been collected for this integrated study through extensive collaborative effort of GSFC¡¦s engineering, mission operations and S&MA directorates. Some important risk insights and conclusions were drawn in support of the risk-informed design decisions not only beneficial to MMS but to future NASA space projects as well.