The Committee on Astronomy and Astrophysics (CAA) is tasked with monitoring the progress of the recommended priorities of the astronomy and astrophysics decadal survey of the National Academies of Sciences, Engineering, and Medicine and providing “an independent, authoritative forum for identifying and discussing issues in astronomy and astrophysics between the research community, the federal government, and the interested public.” The CAA therefore routinely discusses preparations for the next astronomy and astrophysics decadal survey, Astro2020. One of the important pre-survey activities is the definition of mission concepts in a manner that supports the survey process. This short report is the result of a request from NASA. The statement of task is as follows:
In a brief report, the Committee on Astronomy and Astrophysics (CAA) will review NASA’s plans for delivering mission concept studies (large and medium) to the Decadal Survey Committee. The CAA will assess the appropriateness of NASA’s plans and, if needed, provide findings for the purpose of improving the value of NASA’s preparations to the Decadal Survey Committee. NASA will provide information to the CAA on the expectations for each mission concept study, including the content of their final reports, a timeline for their reports’ delivery, and the plans for independent reviews to be conducted by NASA. NASA will also provide to the CAA a proposed list of materials that NASA plans to deliver to the Decadal Survey Committee.
The full process of preparing for Astro2020 that has been undertaken by NASA is described in the material available at https://science.nasa.gov/astrophysics/2020-decadal-surveyplanning. The activities are described here briefly.
In 2013, NASA released a document entitled “Enduring Quests Daring Visions,” which is the result of discussions laying out NASA Astrophysics missions and activities for the next 30 years. Three of the missions described in this study, Far-IR Surveyor, LUVOIR Surveyor, and X-ray Surveyor, have become Origins Space Telescope (OST), Large Ultraviolet Optical Infrared Surveyor (LUVOIR), and Lynx X-ray Surveyor (Lynx), respectively. A fourth large mission, Habitable Exoplanet Imaging Mission (HabEx), has also been defined. These four large mission concepts are being developed by study teams funded by NASA Astrophysics to ensure that all four are well prepared for consideration by Astro2020. Each of these missions has encouraged community participation, and the URLs listed in the Appendix document the meetings, discussions, and work of the study groups. Final reports from each study are to be delivered in summer of 2019 for use by Astro2020 and will include independent cost evaluations but not full-blown cost and technical evaluation (CATE) exercises prior to submission to Astro2020.
In addition to funding four large mission concept studies, NASA Astrophysics also solicited proposals for probe-class studies in August 2016. Ten concepts were selected for funding, with reports due in summer of 2019 for use by Astro2020. These studies are smaller in scope than the four large mission studies and are notionally cost-capped at $1 billion. They could also be called “medium-class” but are larger than Explorers. These distinctions are based on life-cycle costs. They include limited independent cost assessments but not CATEs. It is anticipated