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 http://national-academies.org. A roster follows. 
 
Report: “Powering Science: NASA’s Large Strategic Science Missions (2017)”