The long timescales of spacecraft missions make planning on a decadal timescale appropriate, and the effort required once every 10 years for the science community to produce a decadal survey is substantial. If a midterm assessment is carried out, it must be carefully constructed to reinforce the decadal survey process, while still taking into account any new discoveries or other changes that have taken place.

There are other things that NASA and the planetary science community can do to prepare for the next decadal survey. Two of the most important are as follows:

• Monitoring the implementation of the survey—Agency budgets wax and wane, new scientific discoveries are made, and new technologies come to the fore. Change, both good and bad, has an influence on the planetary science agenda and will affect the implementation of the recommendations in this report. A decadal survey should not be blindly followed if external circumstances dictate that a change in strategy is needed. But who decides if change warrants a deviation from a decadal plan? The potential candidates—internal agency advisory committees, community based “analysis groups,” and NRC committees—are not currently chartered to play such a role. A group specifically tasked to monitor and assess progress toward decadal goals is essential. Such a group should be able to provide the necessary strategic guidance needed to achieve the decadal science goals in a timely manner and consistent with the survey recommendations.

• Mission studies—This decadal survey commissioned numerous mission studies that were carried out over a relatively short period of time and then subjected to cost and technical evaluations. A more effective method would be for NASA to sponsor studies for potential flagship and New Frontiers missions that capture the broadest possible science questions as well as reduce the time pressure on the decadal survey itself. The committee therefore recommends that NASA sponsor community-driven, peer-reviewed mission studies in the years leading up to the next decadal survey, using a common template for the study reports.


1. In 2006 NASA also asked the National Research Council to conduct such an assessment for the agency’s Astrophysics Division. In 2007 NASA asked the NRC for an assessment of the agency’s Heliophysics Division. The NRC is currently undertaking an assessment of the Earth Sciences Division.

2. National Research Council. 2008. Grading NASA’s Solar System Exploration Program: A Midterm Report. The National Academies Press, Washington, D.C.

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