Every decade, the astronomical community of the United States comes together to discuss the future of their field of science. With limited resources, both in terms of research funding and time, astronomers decide what questions they are most interested in and recommend telescopes that can help them answer those questions. It’s a process by astronomers, for astronomers, but their decisions are mostly funded by federal dollars and lead to scientific discoveries and images, which are making their way into public discourse. The Hubble Space Telescope and its breathtaking views of the universe exist in part because of this practice, called the Decadal Survey of Astronomy and Astrophysics. The National Academy of Sciences is due to release its updated 10-year survey later this year, and the astronomical community looks forward to seeing the latest recommendations from a more than 50-year process that has led to some of the most groundbreaking projects and emblematic of modern astronomy. the story.
It takes more than one type of telescope to observe all the light and information traveling to Earth from the near and far universe. This means that different astronomical questions rely on different types of telescopes to answer them. Want to study planets orbiting other stars? You will get the best data by piloting a telescope on an airplane in Earth’s upper atmosphere or, better yet, launching a telescope into space. Want to study supernovae? The high-energy gamma rays created by a supernova explosion can only be studied directly with a space telescope that uses special detectors. What about neutrinos? These elusive particles that can help astronomers discover the sources of cosmic rays are best studied with observatories built deep below the Earth’s surface. Each area of research requires the construction of very different observatories, so astronomers must choose where they want to focus their efforts.
Through the process of prioritizing astronomical questions and instruments, the 10-year survey serves as a recommendation to Congress on the allocation of federal funds to NASA for astronomical research. Large observatories, whether located underground, built on a high mountain, hovered over the atmosphere, or launched into space, are costly efforts and take years of development and construction. Because of these constraints, astronomers often have to decide whether they prefer several small and medium range telescopes or one or two very large telescopes. In addition to prioritizing future research topics and the instruments required for these projects, astronomers also take into account the current state of previously constructed observatories.
The first three decennial surveys prioritized a series of space telescopes that covered the universe from infrared to gamma rays. These four space telescopes have become NASA’s major observatories and have been the foundation of astronomical research in space for the past 30 years. The 1970 report prioritized what became the Hubble Space Telescope and a series of high-energy astrophysical observatories, which led to the development of the Compton Gamma Ray Observatory. The 1980 report prioritized the Chandra X-ray Observatory, and in the 1990s the Spitzer Space Telescope and infrared astronomy received the highest ranking.
In the 2000 and 2010 Decadal Surveys, astronomers focused on pressing questions in astronomy, including: How have galaxies evolved since birth? How do planetary systems form and evolve? What is dark energy? Where are the potentially habitable planets? Two of the priority space telescopes were the Next Generation Space Telescope, now called the James Webb Space Telescope (JWST), and the Wide Field Infrared Telescope, now called the Nancy Grace Roman Space Telescope. The 2000 and 2010 10-Year Surveys also established closer collaboration with international partners in an effort to coordinate large-scale projects that are too costly for the United States to carry out on its own, a crucial element for JWST, whose budget has been strained. significantly increased since its inception. . After several delays, the launch of JWST is currently scheduled for December 2021, after which astronomers hope to meet the expectations of the Decadal Survey and make discoveries that will rival those of the Hubble Space Telescope when it first launches. The launch of the Roman Space Telescope is scheduled for 2025.
Astronomers have proposed four space telescopes for consideration in the 2020s decadal survey:
- The Lynx X-ray Observatory. Lynx would be a significant improvement on the Chandra X-ray Observatory and reveal more precise details of the violent processes that occur around black holes, the explosive nature of the supernova, and other high-energy objects and events in the universe.
- The Habitable Exoplanets Observatory (HabEx). HabEx would take direct images of planets around Sun-like stars and could reveal more about potentially habitable worlds around other stars.
- The Large Ultraviolet Optical Infrared Surveyor (LUVOIR). LUVOIR is a magnified version of the Hubble Space Telescope and would transform our view of exoplanets, stars and galaxies.
- The Origins Space Telescope. This telescope would study the infrared universe and expand our understanding of the origin of solar systems, stars, and galaxies.
Each telescope has its strengths, but together they have the potential to form what astronomer Grant Tremblay calls the New Great Observatories. The Decadal Survey is unlikely to recommend chasing the four telescopes together, but each offers a unique view of the many mysteries in the universe.
The Decennial Survey of Astronomy and Astrophysics holds immense power in guiding future research and discovery. These recommendations to NASA resulted in budget requests and approvals that led to huge advancements in astronomical research and instrumentation. Once the 2020 10-year survey is published and the priorities are established, the next stage of development can begin, where one or more of these telescopes will be launched into space over the next decades.