Impact of Moon-Mars Initiative on Space Science Priorities

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Publication date: 
11 January 2005

"We believe that human exploration...has a role to play in NASA, but it must be within a balanced program in which allocated resources span the full spectrum of space science and take advantage of emerging scientific opportunities and synergies." - Report of the APS Task Force on NASA Funding for Astrophysics

The as-yet-unknown cost of President Bush's initiative to send humans to the Moon and to Mars may delay or damage many of the space science community's highest priority missions, according to a November 2004 report by the American Physical Society's Task Force on NASA Funding for Astrophysics. The task force also argues that sending human missions to the Moon and to Mars would add little to our understanding of the universe.

The task force points out that the normal process for prioritizing astronomy and astrophysics projects, with the involvement of the science community, was bypassed in the development of the Moon-Mars initiative. Additionally, it notes that "no budgetary mechanisms have been established to limit the potential deleterious impact of the program on other aspects of NASA's missions" or on other science agencies. Already, in a September 2004 analysis (see, the Congressional Budget Office estimated that the cost of the Moon-Mars initiative could exceed current estimates by $30-61 billion in the next 15-20 years. The APS report projects that, if the costs grow by $61 billion and funding constraints force NASA to reprogram internal funds to meet this cost growth, "46 percent of total Aeronautics and Other Science funding...would disappear."

The task force's report buttresses a statement released by the APS Executive Board in June 2004, which stated, in part, that "Launching such a massive program without broad consultation and a clear idea of its scope and budget may hurt rather than enhance...the scientific standing of the U.S. and the training of its scientists and engineers." The statement continues, "Before the United States commits to President Bush's proposal, an exhaustive external review of the plans should be carried out by the National Academy of Sciences and their likely budgetary impact estimated by the Government Accountability Office (GAO)."

The task force warns that policymakers face a "major challenge" in reprioritizing NASA programs to implement the Moon-Mars initiative "without destroying the agency's balanced scientific program that was carefully crafted with strong scientific community involvement." The report's authors believe that the space science community, through National Academy of Sciences decadal surveys, advisory committees, and NASA's roadmap process, has established effective mechanisms for soliciting input and achieving consensus from all segments of the community. This priority-setting process was not utilized in development of the Moon-Mars proposal. In fact, the report points out that the Administration's plans for FY 2005 and beyond already call for delays and budget cuts to many space science priorities. They could affect such projects as LISA, Constellation-X, Einstein Probes, the Explorer program, Sun-Earth Connections and future Solar-Terrestrial Probe missions. (In the FY 2005 omnibus appropriations bill, funding for NASA's Science, Aeronautics and Exploration account was reduced even more than the Administration's request; see

In assessing the scientific value of the Moon-Mars initiative, the task force acknowledges that human explorers have some advantages over robotic missions, but finds the use of humans not justified on scientific grounds: "The recent spectacular success of the Mars Rovers reminds us that it is possible to address many important scientific questions by robotic means. The limited autonomy possible with current technology typically reduces the pace at which science is done.... But this is an acceptable compromise given the very large difficulties and costs of using people." The report adds, "Human exploration could offer one real advantage: serendipity, the opportunity to notice and respond immediately to the unexpected. In this regard, astronauts on Mars might achieve greater scientific returns than robotic missions, but at such a high cost and technical challenge that one could not expect to justify their presence on scientific grounds alone." The task force also cautions about contamination of the Mars surface by terrestrial life forms, which would "compromise a prime target of the exploration program, the search for life on another solar system body."

"Returning Americans to the Moon and landing on Mars would have a powerful symbolic significance, but it would constitute only a small step in the advancement of knowledge," the task force concludes, "since much will already be known from exploration with the robotic precursor probes that are necessary to guarantee the safety of any human mission."

These considerations led the task force to propose three recommendations:

1. "NASA should continue to be guided by the recommendations of the National Academy of Sciences (NAS) decadal studies in formulating its science programs."

2. "Before the United States commits to the Moon-Mars proposal, a review of the initiative's science impact should be carried out by the NAS."

3. "Before the United States commits to the Moon-Mars proposal, the likely budgetary impact should be estimated by the Government Accountability Office."

The task force report can be found on the APS Public Affairs site at, under the heading "Research Funding."

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