Decadal Survey Urges New Approach to Flagship Astrophysics Missions

Decadal Survey Urges New Approach to Flagship Astrophysics Missions

The astrophysics community is urging NASA to take a new approach to building flagship space telescopes, the biggest and most expensive in NASA’s portfolio. More effort would be put into maturing concepts and technologies before picking the final design. The first to enter this program would be an infrared/optical/ultraviolet space telescope to search for signatures of life on planets outside our solar system, with an estimated cost of $11 billion and launch in the early 2040s.

These recommendations are from the latest Decadal Survey for astronomy and astrophysics conducted by the National Academies of Sciences, Engineering, and Medicine every 10 years (a decade, hence the term Decadal). Scientists working under the aegis of the Academies prepare Decadal Surveys for each of NASA’s science disciplines, identifying key science questions and recommending missions to answer them. The 1964 astronomy and astrophysics Decadal Survey was the first, but they now also are conducted for planetary science and astrobiology, earth science and applications from space, heliophysics, and biological and physical sciences in space.

Today’s report, Pathways to Discovery in Astronomy and Astrophysics for the 2020s, is the seventh for this discipline. The study was co-chaired by Fiona Harrison of the California Institute of Technology and Robert Kennicutt, Jr. of the University of Arizona and Texas A&M University.

The report takes a very broad look at the current health and long term future of astronomy and astrophysics at NASA, the National Science Foundation (NSF), and the Office of High Energy Physics at the Department of Energy.

For NASA, one of the major recommendations is a “re-imagining” of how flagship missions are planned and executed. The report calls on NASA to create a Great Observatories Mission and Technology Maturation program to reduce risks and costs. Early investments would be targeted there to allow for “co-maturation of mission concepts and technologies, with appropriate decadal survey input on scope, with checks and course corrections along the way.”

At a press conference this afternoon, Harrison and Kennicutt agreed this is the most “impactful” recommendation of the entire report. Harrison said it would be “transformative” because future projects would be planned and developed “more coherently” and “increase the launch rate of very important capabilities over a wide range of wavelengths.” Kennicutt said the new paradigm is needed because the projects span a much longer time span than an individual Decadal Survey. They do not want to tie the hands of future Surveys, but do want a steady stream of projects. “We will get better cost, better value on the money we spend, and then also lower risk at the same time.”

The first program to go through the Great Observatories Mission and Technology Maturation process would be an approximately 6-meter aperture infrared/optical/ultraviolet (IR/O/UV) telescope to observe planets 10 billion times fainter than their star and provide spectroscopic data that could detect signatures indicating life might exist there. The report estimates it would cost $11 billion, a scale so “ambitious” that “only NASA can undertake and for which the U.S. is uniquely situated to lead.” Launch would take place in the first half of the 2040s.

Two of the four Mission Concept Studies sponsored by NASA for consideration by the Decadal Survey, LUVOIR and HabEx, were in the same spectral range as IR/O/UV, but Harrison said each had disadvantages so they came with their own concept. They envision a maturation process that will cost approximately $800 million over 6 years, with a decision by the end of this decade on transitioning into formulation and implementation.

Next into the new process would be two smaller missions: a Far Infra-Red spectroscopy and imaging strategic mission and a high spatial and spectral resolution X-ray strategic mission. Those would be downscaled versions of the other two NASA Mission Concept Studies, Origins (Far IR) and Lynx (X-Ray). They envision spending $40 million per year on each of them beginning in the second half of this decade to begin to get them ready to enter the maturation process 5 years after IR/O/UV.  Total implementation cost is estimated at $3-5 billion each.

Those are just a sample of the recommended ground- and space-based missions spanning several decades of development, implementation and operations to address three broad themes: Worlds and Suns in Context, New Messengers and New Physics, and Cosmic Ecosystems.


Although the Decadal Survey focused on investments for the future, it also commented on some of NASA’s existing programs. In particular, it expressed support for NASA’s intent to terminate the airborne NASA-DLR Stratospheric Observatory for Infrared  Astronomy (SOFIA) by 2023. “The NASA portion of SOFIA’s operating budget is out of balance with its scientific output.”

NASA has proposed terminating SOFIA for several years, but Congress has always restored funding for the international project. For FY2022, the House Appropriations Committee approved $82 million to keep SOFIA flying, but the Senate Appropriations Committee was silent on the matter. It neither added money nor commented about the proposal to terminate the project. How it will fare when the two sides negotiate a final verison of the bill in light of the Decadal Survey’s statement will be interesting to watch. Congress usually follows Decadal recommendations.

The Democratic leadership of the House Science, Space, and Technology Committee issued a joint statement praising the report overall, but not making any commitments. Committee chairwoman Eddie Bernice Johnson (D-TX) is “excited about the bold vision” in the report and urges “NASA, NSF and DOE to carefully review” the recommendations “and begin finding ways to implement them.” Space subcommittee chair Don Beyer (D-VA) added that he is “inspired by the priority scientific questions it identifies” and looks forward to “considering these recommendations in more detail.”

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