Origins, Worlds, and Life: A Decadal Strategy for Planetary Science and Astrobiology 2023-2032

What new discoveries are on the horizon for the next decade of planetary exploration? A new National Academies’ report, Origins, Worlds, and Life: A Decadal Strategy for Planetary Science and Astrobiology 2023-2032, highlights key science questions, identifies priority missions, and presents a comprehensive research strategy that includes both planetary defense and human exploration. The report also recommends ways to support the profession as well as the technologies and infrastructure needed to carry out the science.

KEY SCIENCE QUESTIONS FOR THE NEXT DECADE

The next decade of planetary science and astrobiology holds tremendous promise. New research will expand our understanding of our solar system’s origins, how planets form and evolve, under what conditions life can survive, and where to find potentially habitable environments in our solar system and beyond. The decadal survey defines a set of key science questions that will serve as a critical foundation for the next decade of missions and research.

Origins

What were the initial conditions in the solar system? What processes led to the production of planetary building blocks, and what was the nature and evolution of these materials?

Learn more in Chapter 4.

How and when did the giant planets and their satellite systems originate, and did their orbits migrate early in their history? How and when did dwarf planets and cometary bodies orbiting beyond the giant planets form, and how were they affected by the early evolution of the solar system?

Learn more in Chapter 5.

How and when did the terrestrial planets, their moons, and the asteroids accrete, and what processes determined their initial properties? To what extent were outer solar system materials incorporated?

Learn more in Chapter 6.

Worlds and Processes

How has the population of solar system bodies changed through time, and how has bombardment varied across the solar system? How have collisions affected the evolution of planetary bodies?

Learn more in Chapter 7.

How do the interiors of solid bodies evolve, and how is this evolution recorded in a body’s physical and chemical properties? How are solid surfaces shaped by subsurface, surface, and external processes?

Learn more in Chapter 8.

What establishes the properties and dynamics of solid body atmospheres and exospheres, and what governs material loss to space and exchange between the atmosphere and the surface and interior? Why did planetary climates evolve to their current varied states?

Learn more in Chapter 9.

What processes influence the structure, evolution, and dynamics of giant planet interiors, atmospheres, and magnetospheres?

Learn more in Chapter 10.

What processes and interactions establish the diverse properties of satellite and ring systems, and how do these systems interact with the host planet and the external environment?

Learn more in Chapter 11.

Life and Habitability

What conditions and processes led to the emergence and evolution of life on Earth, what is the range of possible metabolisms in the surface, subsurface and/or atmosphere, and how can this inform our understanding of the likelihood of life elsewhere?

Learn more in Chapter 12.

Where in the solar system do potentially habitable environments exist, what processes led to their formation, and how do planetary environments and habitable conditions co-evolve over time?

Learn more in Chapter 13.

Is there evidence of past or present life in the solar system beyond Earth and how do we detect it?

Learn more in Chapter 14.

Cross-Cutting Topic

What does our planetary system and its circumplanetary systems of satellites and rings reveal about exoplanetary systems, and what can circumstellar disks and exoplanetary systems teach us about the solar system?

Learn more in Chapter 15.

PLANETARY MISSION PROGRAMS AND PRIORITIES

The decadal survey emphasizes the importance of balance across mission cost classes (including flagship, New Frontiers, and Discovery programs) when defining a mission portfolio to maximize overall scientific return.

The decadal survey prioritizes the Uranus Orbiter and Probe (UOP) as the highest priority new Flagship mission for initiation in the decade 2023-2032.

UOP will deliver an in situ atmospheric probe and conduct a multi-year orbital tour that will transform our knowledge of ice giants in general and the Uranian system in particular. UOP science objectives address Uranus’ i) origin, interior, and atmosphere, ii) magnetosphere; and iii) satellites and rings.

The second highest priority new Flagship mission is the Enceladus Orbilander.

Enceladus is a moon of Saturn and an ice-rock world with active plumes of gas and particles that originate from its subsurface ocean. Study of plume material allows direct study of the ocean’s habitability, addressing a fundamental question: is there life beyond Earth and if not, why not? Orbilander will analyze fresh plume material from orbit and during a two-year landed mission. Its main science objectives are: i) to search for evidence of life; and ii) to obtain geochemical and geophysical context for life detection experiments.

Learn more in Chapter 22.

New Frontiers (NF) missions are PI-led and are selected via a competitive process, a model proven effective in maximizing innovation and community involvement. In contrast to the Discovery program, New Frontiers solicitations have been more strategic, restricting proposals to a small number of specific mission themes identified primarily through decadal surveys.

The decadal survey panels prioritized NF mission themes based on how well each would address the priority science questions. Using the panel scientific prioritizations as key input, the steering committee then prioritized themes based on a combination of science merit, programmatic balance across different science questions and destination class, cost, and technical readiness.

The decadal survey prioritizes the following eight mission themes for the New Frontiers 6 (NF-6) call:

  • Centaur orbiter and lander
  • Ceres sample return
  • Comet surface sample return
  • Enceladus multiple flyby
  • Lunar Geophysical Network
  • Saturn probe
  • Titan orbiter
  • Venus In Situ Explorer

The themes recommended for the New Frontiers 7 (NF-7) call should include all those not selected from the above list, with the addition of the Triton Ocean World Surveyor mission.

Recommendation: The NF Phase A-F cost cap, exclusive of quiet cruise phase and launch vehicle costs, should be increased to $1.65 billion in FY25 dollars. A quiet cruise allocation of $30 million per year should be added to this cap, with quiet cruise to include normal cruise instrument checkout and simple flyby measurements, outbound and inbound trajectories for sample return missions, and long transit times between objects for multiple-target missions.

Learn more in Chapter 22.

The Discovery program supports relatively frequent missions that address any science achievable within a specified cost cap, with a central goal to maximize innovative science per total mission cost. The program has made fundamental contributions to planetary exploration and the decadal survey strongly supports its continuation.

Recommendation: The Discovery Phase A through F cost cap should be $800 million in FY25 dollars, exclusive of the launch vehicle, and periodically adjusted throughout the decade to account for inflation. This cap will enable the Discovery Program to continue to support missions that address high-priority science objectives, including those that can reach the outer solar system.

Learn more in Chapter 22.



MARS EXPLORATION

The Perseverance rover on Mars is in the process of collecting samples from Jezero crater. These samples – some over 3.7 billion years old – will provide a geological record crucial for understanding the environmental evolution, prebiotic chemistry, and biology of Mars in ways that cannot be addressed in situ on the planet or with Martian meteorites.

Recommendation:

The highest scientific priority of NASA’s robotic exploration efforts this decade should be completion of Mars Sample Return as soon as is practicably possible with no increase or decrease in its current scope.

Learn more in Chapter 22.

NASA’s Mars Exploration Program has been incredibly successful in advancing our understanding of Mars, the evolution of terrestrial planets, and technology development. The committee strongly supports the continuation of the program and prioritizes the Mars Life Explorer as the next medium-class Mars mission. The Mars Life Explorer will seek out current life and assess modern habitability through the examination of low latitude ice.

Recommendation:

Subsequent to the peak-spending phase of the Mars Sample Return mission, the next priority medium-class mission for the Mars Exploration Program should be Mars Life Explorer.

Learn more in Chapter 22.



LUNAR EXPLORATION

The Lunar Discovery and Exploration Program (LDEP) supports industry partnerships and innovative approaches to accomplishing exploration and science goals, including the Commercial Lunar Payload Services (CLPS) program for lunar landing services. With NASA’s goal to send Artemis astronauts to the lunar surface within this decade, multiple research and technology development investments are required now to enable and optimize high-priority lunar science activities with humans at the Moon.

Recommendation: PSD should execute a strategic program to accomplish planetary science objectives for the Moon, with an organizational structure that aligns responsibility, authority, and accountability.

Recommendation: The advancement of high priority lunar science objectives, as defined by PSD based on inputs from this report and groups representing the scientific community, should be a key requirement of the Artemis human exploration program.

As human exploration advances into the solar system, it is essential that NASA’s science and human directorates work together to deliver ground-breaking science. The Endurance-A sample return mission, a medium-class robotic mission to collect samples from key lunar locations for later retrieval by Artemis astronauts, exemplifies this synergy. This mission would enable the highest priority lunar science not possible through the local collection of limited samples and could revolutionize our understanding of the Moon and the early history of the solar system.

Recommendation: Endurance-A should be implemented as a strategic medium-class mission as the highest priority of the Lunar Discovery and Exploration Program. Endurance-A would utilize CLPS to deliver the rover to the Moon, a long-range traverse to collect a substantial mass of high-value samples, and astronauts to return them to Earth.

Learn more in Chapter 19 and Chapter 22.

lunar exploration

HUMAN EXPLORATION

Human exploration of space inspires our nation and the world while simultaneously benefiting our technology development, economic standing, and scientific knowledge. Human and robotic exploration of the solar system over the next decade and beyond will benefit from a logical, sustained, and science-focused approach. The decadal survey addresses the opportunities for science within the context of current human exploration plans and priorities, as well as areas of planetary science that can support human flight activities. Although humans may eventually travel to the far reaches of the solar system, the Moon and Mars are the most likely near-term, science-rich destinations, based on stated NASA and commercial exploration plans.

For this decade with a near-term plan for human exploration of the Moon and preparatory activities at Mars, the decadal survey emphasizes the importance of carefully crafted collaboration. A program of scientific exploration can be constructed this decade whereby science enables human exploration and human exploration enables science.

Learn more in Chapter 19.

human exploration

PLANETARY DEFENSE AND NEAR EARTH OBJECTS

Planetary defense is an international cooperative enterprise aimed at providing protection to the nations of the world from devastating asteroid and comet impacts. NASA, NSF, and other government agencies play a leading role in developing the capacity to understand the NEO hazard and build a long-term ability to counter a potential impact threat. A robust program of activities in the coming decade will enable the U.S. planetary defense community to forge detection, warning, and mitigation capabilities that will stand as a global example of how to shield society from a destructive yet preventable natural disaster.

Congressionally directed Near Earth Object (NEO) detectiongoals will be ideally advanced by NEO Surveyor, a dedicated, space-based mid-infrared survey telescope currently pending confirmation.

Recommendation: NASA should fully support the development, timely launch, and subsequent operation of NEO Surveyor to achieve the highest priority planetary defense NEO survey goals.

Advancing planetary defense will require assessment of mitigation techniques, as well as the ability to characterize newly identified hazardous objects. NASA’s DART mission, scheduled to impact the moonlet of the binary asteroid 65803 Didymos in 2022, will demonstrate one approach to asteroid deflection.

Recommendation: The highest priority planetary defense demonstration mission to follow DART and NEO Surveyor should be a rapid-response, flyby reconnaissance mission targeted to a challenging NEO, representative of the population of objects posing the highest probability of a destructive Earth impact (~50-to-100 m in diameter). Such a mission should assess the capabilities and limitations of flyby characterization methods to better prepare for a short-warning-time NEO threat.

Learn more in Chapter 18 and Chapter 22.

human exploration

STATE OF THE PROFESSION

The state of the profession (SoP) – including issues of diversity, equity, inclusivity, and accessibility – is central to the success of the planetary science enterprise. Ensuring broad access and participation is required to recruit, retain, and nurture the best talent, and to support continued American leadership in planetary science and astrobiology (PS&AB).

The committee applauds the hard-earned progress that has been made, most notably with respect to the entry and prominence of women in the field. However, much work remains to be done to address persistent and troubling issues of basic representation by race/ethnicity.

The decadal survey’s eight state of the profession recommendations address:

Equity and accountability require accurate and complete data about the SoP. There is an urgent need for data concerning the size, identity, and demographics of the PS&AB community; and workplace climate. Without such data, it cannot be known if the best available talent is being utilized, nor how involvement may be undermined by adverse experiences.

The committee recommends that the PSD adopt the view that bias can be both unintentional and pervasive, and provides actionable steps to assist NASA in identifying where bias exists and in removing it from its processes.

Engaging underrepresented communities at secondary and college levels to encourage and retain them along PS&AB career pathways is essential to creating and sustaining a diverse community.

Ensuring that all community members are treated with respect, developing and enforcing codes of conduct, and providing ombudsperson support to address issues is important for maintaining healthy and productive work environments.

Learn more in Chapter 16.

TOUR OF THE SOLAR SYSTEM

HIGHLIGHTS FROM THE PAST DECADE

New missions and data, advances in theory and modeling, telescopic observations, and laboratory experiments have led to amazing breakthroughs in planetary science and astrobiology over the past decade. Explore key discoveries from across the solar system below and learn more in Chapter 2.

FAQ

The decadal survey identifies the most compelling science challenges and frontiers in planetary science and astrobiology and presents a comprehensive research strategy to advance the field in the next decade and beyond. This is the fourth decadal survey for planetary science conducted over the history of the National Academies, and like its predecessors, it will serve as a guide for scientists, decision makers, and agencies invested in the field.

The National Academies selected committee members in a process independent of sponsoring agencies after casting a wide net for participant recommendations, including an open call for nominations. Members of the steering committee were selected to cover as fully as possible the scientific scope of the survey and to form as representative a group of experts as possible in terms of individual, institutional, and geographical demographics. National Academies policies governing potential conflicts of interest by steering committee and panel members were strictly enforced. In particular, broad and open-minded thinkers were sought out as opposed to advocates for individual missions or subfields.

The information gathering and deliberative phases of the decadal survey were carefully coordinated. Members of the planetary science and astrobiology communities were invited to submit whitepapers to the survey, and these papers formed the foundation and starting point for all of the panel and working group deliberations. There were three separate calls for whitepapers over the course of the survey, focusing on science, programmatic and mission concepts, and the state of the profession. The survey received close to 600 whitepapers in total. Every whitepaper was assigned to and read by one or more of the decadal panels.

The study was led by a 19 member steering committee that was advised by 6 additional panels organized by planetary destination:

Science Panels

  • Panel on Giant Planet Systems
  • Panel on Ocean Worlds and Dwarf Planets
  • Panel on Mercury and the Moon
  • Panel on Mars
  • Panel on Venus
  • Panel on Small Solar System Bodies

The decadal survey’s statement of task charged the committee with addressing the state of profession (SoP), including issues of diversity, equity, inclusion, and accessibility. This decadal survey presents a substantive discussion of these issues to signal their importance and urgency. The decadal survey steering committee–which included a social scientist to provide critical insight into these issues–engaged with available SoP data, white papers submitted to the decadal, invited speakers, robust internal discussions, as well as the best social, behavioral, and neuroscience evidence about the causes and outcomes that affect the quality of STEM professions. The decadal survey presents findings and recommendations that flow from this analysis with the goal of building a strong system of equity and accountability to nurture and sustain the field. As requested in the statement of task, these recommendations are actionable and intended to help NASA PSD bring the full force of its leadership and the engagement of the community to advance the profession as part of its scientific mission. Learn more about this effort in Chapter 16.

This decadal survey was sponsored by the National Aeronautics and Space Administration (NASA) and the National Science Foundation (NSF).

Download the Report and Report Resources

RELATED RESOURCES:

Image Credits:
Background/Cover Images: Conrad Ziebland; ESO/L. Calçada; NASA; ESA/OSIRIS Team MPS/UPD/LAM/IAA/RSSD/INTA/UPM/DASP/IDA/Gordan Ugarković; ESA/Hubble, M. Kornmesser; NASA/ESA/Hubble Heritage Team (STScI-AURA); MARUM−Zentrum für Marine Umweltwissenschaften, Universität Bremen; ESO/S. Brunier • Mars Exploration Section: NASA/ESA/JPL-Caltech; MOLA Science Team • Lunar Exploration Section: LPI • Human Exploration Section: NASA • Planetary Defense Section: NASA/Johns Hopkins, APL/Steve Gribben • Highlights Section: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington; NASA/GSFC/Arizona State University; JAXA/ISAS/DARTS/K. M. Gill/P. K. Byrne; ESA/DLR/FU-Berlin; NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute; NASA/JPL-Caltech; NASA/JPL/Space Science Institute