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Probabilistic Mass Growth Uncertainties

Risk I Track



Mass has been widely used as a variable input parameter for Cost Estimating Relationships (CER) for space systems. As these space systems progress from early concept studies and drawing boards to the launch pad, their masses tend to grow substantially hence adversely affecting a primary input to most modeling CERs. Modeling and predicting mass uncertainty, based on historical and analogous data, is therefore critical and is an integral part of modeling cost risk. This paper presents the results of an ongoing NASA effort to publish mass growth datasheet for adjusting single-point Technical Baseline Estimates (TBE) of masses of space instruments as well as spacecraft, for both earth orbiting and deep space missions at various stages of a project’s lifecycle This paper will also discusses the long term strategy of NASA Headquarters in publishing similar results, using a variety of cost driving metrics, on an annual bases. Paper will provide quantitative results that show decreasing mass growth uncertainties as mass estimate maturity increases. This paper’s analysis is based on historical data obtained from the NASA Cost Analysis Data Requirements (CADRe) database.


Eric Plumer
NASA HQs – Cost Analysis Division
As a cost analyst for 17 years, Eric Plumer directs and manages NASA’s Cost Analysis Data Requirements (CADRe) program within the Office of Cost Evaluation at NASA HQs. As the lead for CADRe, he is responsible for planning, prioritizing, funding, and directing, supporting data collection, and review and approval on dozens of CADRe events for both on-going and historical flight projects at NASA. He is also the lead for the ONCE Database that is now operational and performs full storage, search, and analysis tools for CADRe data. In addition Eric provides program analysis on various NASA project as an agency expert to ensure programmatic cost and schedule risks are analyzed to ensure success in meeting mission critical goals and objectives.
Eric’s cost career began in the Air Force where he worked in the Air Force Cost Analysis Agency for 7 years. While working in both the aircraft and space divisions he served as cost analyst on many ACAT I programs including, B-2, F-22, V-22, F-35, NPOESS, Advanced EHF and EELV. He also spent the two years at AFCAA serving as acting chief and manager for the AFCAA Cost Research program. Previous to working at NASA he worked 4 years at the Internal Revenue Service where he was the lead for developing, reviewing, and running labor forecasting models including the IRS Labor Cost Model (LCM). Eric has degrees in Finance, and Information Technology. He was SCEA certified in 2009 in Cost Estimating/Analysis and is Level III DoD Certificated in Financial Management and Cost Estimating.