Affordability assessments to support strategic planning and decisions at NASA

NASA's goal to provide a human presence in space while contributing to the knowledge of the science of Earth, other planets, the solar system, and the universe requires a diverse set of scientific and exploration missions. Successful development and execution of these portfolios depends upon a sustainable and affordable long-term strategy. To provide a basis for an adequate annual funding profile to fit within NASA's budget, an objective affordability assessment of a mission's technical baseline, associated risks, and cost and schedule is fundamental. For example, NASA's Science Mission Directorate lists close to 100 planned science missions for launch within a 20-year window in the Agency Mission Planning Manifest maintained by the NASA Office of Program Analysis and Evaluation. On the human space flight side, the NASA Exploration Systems Mission Directorate (ESMD) is in the process of trying to develop several multi-billion dollar systems (e.g. Orion capsule, Ares launch vehicle, etc.) in parallel to meet an initial operational capability within the next 10 years. While portfolios such as these might be defined such that the estimated life-cycle costs are covered by the expected budget, there are a variety of factors that might initiate a need to re-plan the portfolio, including budget cuts, new mission content, new Administration direction, different reserves strategies, and cost and schedule overruns. This can be seen in the 2009 Review of U.S. Human Space Flight (HSF) Plans Committee initiated by the White House, which examined the ongoing U.S. human space flight plans and programs, as well as alternatives to the current program of record. Using an affordability analysis process developed by The Aerospace Corporation, assessments were performed using the Sand Chart Tool (SCT) to support these portfolio analyses. SCT was developed to provide insight into the behavior of large portfolios and strategic issues associated with re-plans and execution of the specified content. It can run in two modes: Planning Mode, which applies a temporal stretch algorithm to fit portfolio costs to the budget (by stretching out schedule as necessary), and Evaluation Mode, which performs a probabilistic Monte Carlo analysis to determine the robustness of a given plan after considering cost-growth risks, schedule linkages, and other factors. This paper will 1) look at why affordability analysis is important in managing complex/high-value Agency portfolios, 2) provide a general overview of SCT and the affordability analysis process, and 3) examine recent examples of affordability assessments performed on the ESMD portfolio in support of the Review of HSF Committee.