In 1988 the National Academy of Sciences and the National Academy of Engineering stated in the report, Toward a New Era in Space: Realigning Policies to New Realities, that “the ultimate decision to undertake further voyages of human exploration and to begin the process of expanding human activities into the solar system must be based on nontechnical factors.” It is clear, however, that if and when a program of human exploration is initiated, the U.S. research community must play a central role by providing the scientific advice necessary to help make the relevant political and technical decisions.
Since its establishment in 1958, the Space Studies Board (SSB; formerly the Space Science Board) has been the principal nongovernmental advisory body on civil space research in the United States. In this capacity, the board established the Committee on Human Exploration (CHEX) in 1989 to examine many of the science and science policy matters concerned with the return of astronauts to the Moon and eventual voyages to Mars. The board asked CHEX to consider three major questions:
What scientific knowledge must be obtained as a prerequisite for prolonged human space missions?
What scientific opportunities might derive from prolonged human space missions?
What basic principles should guide the management of both the prerequisite science activities necessary to enable human exploration and