Finally, the panel is concerned about the process by which NASA’s decision to propose two TPF missions and to start one of them this decade was reached. The statement of task asked for input on the likely impacts on the 2000 decadal survey priorities, and these are large. The plan for TPF-C is clearly not consistent with the 2000 decadal survey’s recommendations regarding TPF.

Even though NASA has rearranged the order of missions occasionally in the past when funding or technology concerns warranted such changes, TPF-C is so expensive and challenging that the panel believes that, from the perspective of astronomy and astrophysics,6 it must be placed in the broader context of the other highly ranked space missions identified in the 2000 decadal survey. The panel is very concerned about breaking with a process for developing a strategy that has served astronomy and astrophysics very well—the broadly debated, carefully balanced, and widely endorsed portfolio that the 2000 decadal survey presented. If implementation of TPF-C were to delay, or even preclude, other highly ranked astronomy and astrophysics missions, such an outcome would represent a substantial tipping of the portfolio’s scientific balance. The panel urges NASA to consider the addition of TPF-C within the broader context of the entire astronomy and astrophysics program.

Signed by

Wendy L. Freedman

Chair, Panel to Review the Science Requirements for the Terrestrial Planet Finder


The panel acknowledges that the TPF mission is of interest to disciplines throughout the space sciences, and that the mission could conceivably be of higher priority to other disciplines.

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