NASA's Science Mission Directorate (SMD) currently operates over five dozen missions, with approximately two dozen additional missions in development. These missions span the scientific fields associated with SMD's four divisionsâ€"Astrophysics, Earth Science, Heliophysics, and Planetary Sciences. Because a single mission can consist of multiple spacecraft, NASA-SMD is responsible for nearly 100 operational spacecraft. The most high profile of these are the large strategic missions, often referred to as "flagships." Large strategic missions are essential to maintaining the global leadership of the United States in space exploration and in science because only the United States has the budget, technology, and trained personnel in multiple scientific fields to conduct missions that attract a range of international partners. This report examines the role of large, strategic missions within a balanced program across NASA-SMD space and Earth sciences programs. It considers the role and scientific productivity of such missions in advancing science, technology and the long-term health of the field, and provides guidance that NASA can use to help set the priority of larger missions within a properly balanced program containing a range of mission classes.

Principal Investigator-Led (PI-led) missions are an important element of NASA's space science enterprise. While several NRC studies have considered aspects of PI-led missions in the course of other studies for NASA, issues facing the PI-led missions in general have not been subject to much analysis in those studies. Nevertheless, these issues are raising increasingly important questions for NASA, and it requested the NRC to explore them as they currently affect PI-led missions. Among the issues NASA asked to have examined were those concerning cost and scheduling, the selection process, relationships among PI-led team members, and opportunities for knowledge transfer to new PIs. This report provides a discussion of the evolution and current status of the PIled mission concept, the ways in which certain practices have affected its performance, and the steps that can carry it successfully into the future. The study was done in collaboration with the National Academy of Public Administration.

As civil space policies and programs have evolved, the geopolitical environment has changed dramatically. Although the U.S. space program was originally driven in large part by competition with the Soviet Union, the nation now finds itself in a post-Cold War world in which many nations have established, or are aspiring to develop, independent space capabilities. Furthermore discoveries from developments in the first 50 years of the space age have led to an explosion of scientific and engineering knowledge and practical applications of space technology. The private sector has also been developing, fielding, and expanding the commercial use of space-based technology and systems. Recognizing the new national and international context for space activities, America's Future in Space is meant to advise the nation on key goals and critical issues in 21st century U.S. civil space policy.

Three recent developments have greatly increased interest in the search for life on Mars. The first is new information about the Martian environment including evidence of a watery past and the possibility of atmospheric methane. The second is the possibility of microbial viability on Mars. Finally, the Vision for Space Exploration initiative included an explicit directive to search for the evidence of life on Mars. These scientific and political developments led NASA to request the NRC's assistance in formulating an up-to-date integrated astrobiology strategy for Mars exploration. Among other topics, this report presents a review of current knowledge about possible life on Mars; an astrobiological assessment of current Mars missions; a review of Mars-mission planetary protection; and findings and recommendations. The report notes that the greatest increase in understanding of Mars will come from the collection and return to Earth of a well-chosen suite of Martian surface materials.

This book is in full-color - other editions may be in grayscale (non-color). The hardback version is ISBN 9781680920512 and the paperback version is ISBN 9781680920505. The NASA Space Flight Program and Project Management Handbook (NASA/SP-2014-3705) is the companion document to NPR 7120.5E and represents the accumulation of knowledge NASA gleaned on managing program and projects coming out of NASA's human, robotic, and scientific missions of the last decade. At the end of the historic Shuttle program, the United States entered a new era that includes commercial missions to low-earth orbit as well as new multi-national exploration missions deeper into space. This handbook is a codification of the "corporate knowledge" for existing and future NASA space flight programs and projects. These practices have evolved as a function of NASA's core values on safety, integrity, team work, and excellence, and may also prove a resource for other agencies, the private sector, and academia. The knowledge gained from the victories and defeats of that era, including the checks and balances and initiatives to better control cost and risk, provides a foundation to launch us into an exciting and healthy space program of the future.