The president’s recently released Fiscal Year 2019 budget gives NASA an overall increase in funding—certainly something to celebrate in the current fiscally constrained environment. Clearly, however, with so much NASA could do that is inspirational, important and innovative, there will always be choices and tradeoffs to be made. With that in mind, the National Academy of Sciences, Engineering, and Medicine (NASEM) developed a process to help the federal government prioritize science at NASA. Every 10 years, the organization brings science communities together to produce documents that explicitly lay out the scientific priorities and missions that NASA should execute in the coming decade in various areas: astronomy and astrophysics; planetary science; heliophysics; Earth science; and science conducted on the International Space Station.

As former NASA chief scientists, we have been intimately involved in making these kinds of hard choices, and these so called decadal surveys, with their carefully developed, community-based recommendations, have been tremendously valuable tools for ensuring those choices are made responsibly and most effectively. But the current budget proposal cancels several high priority missions recommended in decadal surveys, undermining a 50-year-old process that has long had bipartisan support from the executive and legislative branches of government along with the scientific community. These cancellations could potentially damage our ability to understand our own planet and the universe that surrounds us.

In 2010, NASEM released its latest decadal report, titled “New Worlds, New Horizons in Astronomy and Astrophysics”, which ranked the Wide Field Infrared Survey Telescope (WFIRST) as its highest space-based priority. WFIRST would follow on from the Hubble Space Telescope and the James Webb Space Telescope (JWST, to be launched next year). With a hundredfold bigger field of view than Hubble, it would help scientists tackle problems from the nature of dark energy to the evolution of galaxies, and could directly image worlds around other stars to investigate their properties.

Big telescope missions like WFIRST take years of instrument development and testing. To have the capability to explore the farthest reaches of the universe in place in the mid 2020s and capitalize on the findings of JWST, therefore, requires investments today. Despite the fact that significant investment has already been spent on its development, WFIRST has been defunded in the president’s FY19 budget proposal, threatening to create a gap of unknown length, and potentially ending the U.S.’s leadership in the exploration of deep space.

The previous Earth Science decadal survey, published in 2007, listed as its highest priorities missions to study ocean color (which is indicative of the uptake of carbon dioxide from the atmosphere); clouds and aerosols (small particles that affect Earth’s climate); and heating processes in Earth’s atmosphere. All three of these high priority missions have also been canceled in the FY19 budget proposal. Underscoring the disregard for carefully chosen priorities is that fact that the most recent Earth science decadal survey (released in 2018) reaffirmed the importance and prioritization of those items, which are currently under development as a result of NASA’s efforts to adhere to the 2007 decadal survey.

Moreover, as with WFIRST, a significant amount of the development costs of these missions has been invested already. The net result is that not only will missions aimed at addressing some of the highest priority observations be cancelled, but investments to date will be wasted, and the benefits of such investments unrealized. Such actions are neither scientifically nor economically prudent.  

Each decadal survey takes about two years to complete and ultimately involves hundreds of scientists and a thorough peer-review process. Hundreds of white papers are submitted by the scientific community to allow for an open and comprehensive survey of the key scientific challenges in a given field. Decadal survey panel members spend long hours debating which measurements and missions would allow for substantive progress in addressing questions of primary importance—and which of these are technically ready to be flown in the coming decade. In the process, they make hard choices about what priorities should and should not be recommended for support in the face of the fiscal realities that all agencies face. Survey recommendations carefully take into account not just realistic budget projections, but recommendations as to possible paths of action if budgets increase or decrease.

Canceling missions that are top priority decadal recommendations is not good policy, and will damage our ability to understand the planet we live on, and our search for habitable worlds beyond Earth. We urge the scientific community and the public to stand behind the NASEM decadal process as the best, most nonpartisan, method to determine NASA’s science spending priorities. Otherwise we undermine a process that has been carefully thought out to serve the nation’s interests by ensuring that U.S. taxpayer dollars go towards addressing the most significant scientific and societally beneficial challenges.