Book excerpt: When the space exploration initiative was announced, Congress asked the NRC to review the science NASA proposed to carryout under the initiative. It also asked the NRC to assess whether this program would provide balanced scientific research across the established disciplines supported by NASA in addition to supporting the new initiative. In 2005, the NRC released three studies focusing on a portion of that task, but changes at NASA forced the postponement of the last phase. This report presents that last phase with an assessment of the health of the NASA scientific disciplines under the budget requests imposed by the exploration initiative. The report also provides an analysis of whether the science budget appropriately reflects cross-disciplinary scientific priorities.