Aug. 24, 2017


NASA Should Continue its Large Strategic Missions to Maintain United States’ Global Leadership in Space

WASHINGTON – NASA’s large strategic missions like the Hubble Space Telescope, the Curiosity rover on Mars, and the Terra Earth observation satellite are essential to maintaining the United States’ global leadership in space exploration and should continue to be a primary component of a balanced space science program that includes large, medium, and smaller missions, says a new report by the National Academies of Sciences, Engineering, and Medicine.  However, controlling the costs of these large missions remains vital in order to preserve the overall stability of the program, the report finds. 

NASA’s large space science missions play critical roles in each of the agency’s four science divisions – astrophysics, earth science, heliophysics, and planetary science – and are needed to pursue compelling scientific questions. When faced with determining how to balance the development and operation of the largest flagship missions as part of a balanced program, NASA should seek guidance from the relevant National Academies decadal surveys and midterm reviews, as well as from other research-community based advisory bodies, said the committee that wrote the report.

The committee also recommended that mission advocates describe ranges of scientific scope such as minimum science goals and maximum budgets for the largest missions, as well as identify in decadal surveys what goals are most desirable at different budget levels. This approach will allow NASA to develop, if needed, less expensive implementation strategies (known as “de-scoping”) for missions so that they do not exceed budget constraints that may arise in the future. It could also identify opportunities to “up-scope” such missions to perform greater science, should budgets and the program balance allow.

In the past, concerns have been raised about NASA’s large missions as there has been a history of their costs exceeding original estimates, impacting the overall budget of the agency.  The James Webb Space Telescope (JWST) is a recent example of a large mission that experienced substantial cost growth.  Big jumps in costs for a mission can have an impact on the entire science program at NASA.   

Although cost-evaluation and cost-management mechanisms developed at NASA over the past decade have proved to be effective, NASA should continue to use its various cost estimation and management tools to better assess and control the costs and risks of the missions and ensure they remain a viable option, the report says. The agency should also support the development of new estimation tools to perform robust cost estimates and risk assessment for future missions.  

“New technologies will require new methods of estimating costs,” said Kathryn Thornton, committee co-chair and director of the aerospace engineering program at the University of Virginia, who also helped repair the Hubble Space Telescope during its first in-orbit servicing mission. “Although NASA has gotten better at developing such tools, the agency will have to adapt its ways as technology evolves.”

Given that the scientific priorities for the agency are determined by the decadal surveys, the committee also recommended that the surveys should be informed by, but not restricted to, future projections of available budgets. Such flexibility may enable new and potentially revolutionary large strategic missions.

The study was sponsored by National Aeronautics and Space Administration.  The National Academies of Sciences, Engineering, and Medicine are private, nonprofit institutions that provide independent, objective analysis and advice to the nation to solve complex problems and inform public policy decisions related to science, technology, and medicine. They operate under an 1863 congressional charter to the National Academy of Sciences, signed by President Lincoln. For more information, visit A roster follows.  


Riya V. Anandwala, Media Relations Officer
Andrew Robinson, Media Relations Assistant
Office of News and Public Information
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Copies of Powering Science — NASA’s Large Strategic Science Missions are available at or by calling 202-334-3313  or 1-800-624-6242. Reporters may obtain a copy from the Office of News and Public Information (contacts listed above).


Division on Engineering and Physical Sciences

Space Studies Board

Committee on Strategic NASA Science Missions

Ralph L. McNutt Jr. (co-chair)
Senior Space Physicist
Applied Physics Laboratory
Johns Hopkins University
Laurel, Md.

Kathryn C. Thornton (co-chair)
Director of Aerospace Engineering Program and Professor
Department of Mechanical and Aerospace Engineering
University of Virginia

David A. Bearden
General Manager
NASA and Civil Space Division
The Aerospace Corp.
Pasadena, Calif.

Joel N. Bregman
H.D. Curtis Professor of Astronomy
Department of Astronomy
University of Michigan
Ann Arbor

Anny Cazenave*
Director of Earth Science
International Space Studies Institute
Bern, Switzerland, and
Deputy Director
Laboratoire d’Études en Geophysique et Oceanographie Spatiales
Observatoire Midi-Pyrénées
Toulouse, France

Anne R. Douglass
Senior Scientist
Atmospheric Chemistry and Dynamics Laboratory
NASA Goddard Space Flight Center
Greenbelt, Md.

Victoria E. Hamilton
Principal Scientist
Southwest Research Institute
Boulder, Colo.

Marc L. Imhoff
Visiting Research Scientist
Earth System Science Interdisciplinary Center
University of Maryland
College Park

Charles D. Norton
Program Manager and Principal Technologist
Jet Propulsion Laboratory
California Institute of Technology

Carol S. Paty
Associate Professor
School of Earth and Atmospheric Sciences
Georgia Institute of Technology

Marc D. Rayman
Jet Propulsion Laboratory
California Institute of Technology

William S. Smith
Vice President
ScienceWorks International
Washington, D.C.

Edward L. Wright*
Department of Physics and Astronomy
University of California
Los Angeles

Gary P. Zank*
Center for Space Physics and Aeronomic Research, and
Eminent Scholar, Distinguished Professor, and Chair
Department of Space Science
University of Alabama


Dwayne A. Day
Study Director

*Member, National Academy of Sciences