The Committee on Astrobiology and Planetary Sciences of the National Academies of Sciences, Engineering, and Medicine is tasked with monitoring the progress in implementation of the recommendations of the most recent planetary science decadal survey, Vision and Voyages for Planetary Science in the Decade 2013-2022. Planetary science decadal surveys evaluate the state of the field, identify the most important scientific questions and themes, and prioritize missions and activities for the decade in question based on scientific merit, technical feasibility, and anticipated cost. The need for careful monitoring is underscored by the fact that some of the decadal survey's recommendations are triggered at specific programmatic decision points. Options for the Fifth New Frontiers Announcement of Opportunity addresses one such decision point. For each of the following four New Frontiers targets: Ocean Worlds, Trojan Tour and Rendezvous, Io Observer and Lunar Geophysical, this report summarizes changes in scientific understanding or external factors since the release of Vision and Voyages or its midterm review and considers whether those changes have been sufficiently substantial to warrant reconsideration of the four targets for inclusion in the New Frontiers 5 announcement of opportunity, scheduled for release in early 2022.

This study discusses the publicly available studies of future flagship- and New Frontiers-class missions NASA initiated since the completion of Vision and Voyages. The report considers the priority areas as defined in Vision and Voyages where publicly available mission studies have not been undertaken; appropriate mechanisms by which mission-study gaps might be filled in the near- to mid-term future; and other activities that might be undertaken in the near- to mid-term future to optimize and/or expedite the work of the next planetary science decadal survey committee.

The Committee on Astrobiology and Planetary Sciences of the National Academies of Sciences, Engineering, and Medicine is tasked with monitoring the progress in implementation of the recommendations of the most recent planetary science decadal survey, Vision and Voyages for Planetary Science in the Decade 2013-2022. Planetary science decadal surveys evaluate the state of the field, identify the most important scientific questions and themes, and prioritize missions and activities for the decade in question based on scientific merit, technical feasibility, and anticipated cost. The need for careful monitoring is underscored by the fact that some of the decadal survey's recommendations are triggered at specific programmatic decision points. Options for the Fifth New Frontiers Announcement of Opportunity addresses one such decision point. For each of the following four New Frontiers targets: Ocean Worlds, Trojan Tour and Rendezvous, Io Observer and Lunar Geophysical, this report summarizes changes in scientific understanding or external factors since the release of Vision and Voyages or its midterm review and considers whether those changes have been sufficiently substantial to warrant reconsideration of the four targets for inclusion in the New Frontiers 5 announcement of opportunity, scheduled for release in early 2022.

On December 11, 2017, President Donald Trump signed Space Policy Directive-1 (SPD-1). The new directive replaced original text in the National Space Policy of the United States of America and instructed the Administrator of the National Aeronautics and Space Administration (NASA) to "lead the return of humans to the Moon for long-term exploration and utilization, followed by human missions to Mars and other destinations". In response to and in support of the vision expressed in SPD-1, the first report reviewed decadal and other community-guided lunar science priorities as context for NASA's current lunar plans and then presented and evaluated the actions being taken by NASA's Planetary Science Division (PSD) to support lunar science. At the request of NASA PSD, this second report explores plans for commercial partnerships, lunar infrastructure development, and related aspects of NASA's lunar science and exploration initiative.

Astrobiology is the study of the origin, evolution, distribution, and future of life in the universe. It is an inherently interdisciplinary field that encompasses astronomy, biology, geology, heliophysics, and planetary science, including complementary laboratory activities and field studies conducted in a wide range of terrestrial environments. Combining inherent scientific interest and public appeal, the search for life in the solar system and beyond provides a scientific rationale for many current and future activities carried out by the National Aeronautics and Science Administration (NASA) and other national and international agencies and organizations. Requested by NASA, this study offers a science strategy for astrobiology that outlines key scientific questions, identifies the most promising research in the field, and indicates the extent to which the mission priorities in existing decadal surveys address the search for life's origin, evolution, distribution, and future in the universe. This report makes recommendations for advancing the research, obtaining the measurements, and realizing NASA's goal to search for signs of life in the universe.