SUMMARY

Linked technical, cost, and schedule estimates were developed for each of the priority mission concepts selected by the committee. The use of historical experience databases and evaluation of the technical risk, cost, and schedule histories of analogous space systems that had already flown plus the extensive interaction of technical, cost, and schedule experts with the proposing teams provide, in toto, a high degree of confidence that the resulting assessments are realistic and credible.

The CATE process estimated mission costs that are considerably higher than the cost estimates provided by the design center study teams. The reason is that project-derived cost estimates are typically done using a bottom-up or so-called grass roots approach, and beyond standard contingencies they do not include probabilities of risk incurred by necessary redesigns, schedule slips, or launch vehicle growth. In other words, project estimates typically do not account for the “unpleasant surprises” that historically happen in nearly all space mission developments.

CATEs include a probabilistic assessment of required reserves assuming that the concept achieves the mass and power as allocated or constrained by the respective stated project contingencies within the schedule as stated by the project. In addition to these reserves, additional cost threats are also included that quantify potential cost growth based on design maturity (mass and power growth) and schedule growth. Potential cost threats for larger required launch vehicle capability are also included. It is the combination of these reserves and cost threats that are often the main reason for the large differences between the CATE appraisal and the project estimate. Differences in the estimates for hardware costs (instruments and flight systems) can also be a contributing factor.

As noted in several places in this report, the planetary program has been plagued for many years by use of cost estimates that, in retrospect, turn out to have been too optimistic. The result has been cost overruns that can be highly disruptive to the program. The CATE process, which uses history as its guide, has been designed and is used in this decadal survey to prevent this problem.

NOTES AND REFERENCES

1. National Research Council. 2006. An Assessment of Balance in NASA’s Science Programs. The National Academies Press, Washington, D.C., p. 32.

2. National Research Council. 2006. An Assessment of Balance in NASA’s Science Programs. The National Academies Press, Washington, D.C., p. 33.

3. National Research Council. 2007. Decadal Science Strategy Surveys: Report of a Workshop. The National Academies Press, Washington, D.C., pp. 21-30.

4. National Research Council. 2007. NASA’s Beyond Einstein Program: An Architecture for Implementation. The National Academies Press, Washington, D.C., pp. 66-114.

5. Congress of the United States. 2008. National Aeronautics and Space Administration Authorization Act of 2008. Public Law 110-422, Section 1104b, October 15.

6. National Research Council. 2010. New Worlds, New Horizons in Astronomy and Astrophysics. The National Academies Press, Washington, D.C., Appendix C.

7. As described in Chapter 9, the Mars Sample Return Lander mission is expected to be carried out jointly with the European Space Agency (ESA). Because the details of this collaboration have not been negotiated yet, however, the cost calculated for this mission does not include any ESA contribution.

8. As described in Chapter 9, the Mars Sample Return Orbiter mission is expected to be carried out jointly with the European Space Agency (ESA). Because the details of this collaboration have not been negotiated yet, however, the cost calculated for this mission does not include any ESA contribution.



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