Origins, Worlds, and Life: The National Academies’ Planetary Science and Astrobiology Decadal Survey 2023-2032

ProveKey Takeaways

• The survey names the Uranus Orbiter and Probe as the top new flagship mission priority.
• Mars Sample Return, the survey’s highest overall priority, was effectively cancelled by Congress in January 2026.
• The FY2027 White House budget proposes a 47% cut to NASA science, repeating a pattern Congress rejected in 2026.

What the Decadal Survey Actually Is

Every ten years, the National Academies of Sciences, Engineering, and Medicine assembles the planetary science community to do something that most fields never attempt: reach a documented, peer-reviewed consensus on where scientific attention and public funding should go for an entire decade. The result is the Planetary Science Decadal Survey, a document that carries no legal force but commands enormous practical influence over how NASA and the National Science Foundation allocate resources.

The current edition, titled Origins, Worlds, and Life: A Decadal Strategy for Planetary Science and Astrobiology 2023-2032, was released on April 19, 2022. At 780-plus pages, it’s the product of nearly two years of deliberation, hundreds of community white papers, and input from dozens of scientists organized across a steering committee and six specialized panels. Robin Canup of the Southwest Research Institute and Phil Christensen of Arizona State University co-chaired the steering committee.

It’s the fourth decadal survey the National Academies has produced for planetary science since the field became a structured scientific discipline. Each iteration updates and extends the previous one; this survey updates the 2011 document, Visions and Voyages for Planetary Science in the Decade 2013-2022, which had set the stage for the Perseverance rover and Europa Clipper missions.

How the Survey Was Built

The process is deliberately bottom-up. Scientists at universities, NASA centers, and research institutes submit white papers proposing ideas, outlining scientific priorities, and responding to calls for input. The Bulletin of the American Astronomical Society published an entire volume, Vol. 53, Issue 4, dedicated to whitepapers submitted to this survey. There were hundreds of them.

The steering committee then synthesized this input against a framework defined by the statement of task: broadly canvas the field, determine the current state of knowledge, identify the most important scientific questions for the 2023-2032 interval, and propose missions and programs accordingly. For the first time, planetary defense was formally included as a dedicated chapter, recognizing that protecting Earth from near-Earth object impacts is now treated as a core element of planetary science, not a tangential concern.

NASA’s Science Mission Directorate chartered the survey, with additional support from the National Science Foundation. The steering committee was selected through a process independent of the sponsoring agencies, and the final recommendations were required to be achievable within realistic budget boundaries, not just aspirational wish lists.

Twelve Questions Organizing the Science

Rather than organizing the survey around specific planets, the committee structured scientific priorities around twelve broad questions grouped into three overarching themes: Origins, Worlds and Processes, and Life and Habitability. This approach, different from earlier decadals, was designed to evaluate mission proposals against scientific merit across categories rather than defaulting to an object-by-object pecking order.

The Origins theme addresses questions about the initial conditions of the solar system, how planetary building blocks formed and evolved, and how and when the giant planets and their satellite systems originated. It also asks how dwarf planets and cometary bodies beyond the giant planets formed and what the early solar system’s evolution did to them.

Worlds and Processes covers how solid bodies across the solar system acquired and lost their atmospheres and volatiles, how interior processes shaped planetary surfaces and drove geological evolution, and what the solar wind and space environment have done to airless bodies like the Moon and Mercury.

The Life and Habitability theme brings together questions about the history of organic chemistry and prebiotic processes in the solar system, where liquid water environments exist today and how stable they are, and whether life exists anywhere beyond Earth. That last question draws public attention, even if the survey’s actual language around it is appropriately measured.

The Flagship Mission Priorities

When it comes to large, expensive missions, the survey’s hierarchy was clear at the time of its publication.

The single highest programmatic priority was completing Mars Sample Return (MSR), the collaborative campaign between NASA and the European Space Agency to retrieve samples currently being cached by Perseverance and return them to Earth. The Perseverance rover has been operating in Jezero Crater since February 2021, and as of July 2025 had filled 33 of its 43 sample tubes with rock cores, regolith, and atmospheric samples from what was once a lake and river delta environment. Getting those samples to an Earth laboratory would unlock the kind of detailed isotopic and chemical analysis impossible from any rover. The survey’s endorsement was always conditional: if costs grew uncontrollably, the committee’s decision rules called for restructuring rather than allowing MSR to cannibalize the rest of the planetary program.

That conditionality turned out to matter enormously, because MSR did not survive intact into the current funding environment. More on that below.

For new flagship missions, the top priority is the Uranus Orbiter and Probe (UOP). The UOP would deliver an in situ atmospheric probe and conduct a multi-year orbital tour, addressing Uranus’s origin, interior, atmosphere, magnetosphere, and its system of rings and moons. The survey anticipated the Uranus mission would cost $4.2 billion in fiscal year 2025 dollars and stated that it carries the lowest technical risk of all the flagship mission concepts that were analyzed. No new technologies are required for the UOP mission, and it was described as technically ready to start. Optimal launch windows in 2031 or 2032 would allow a gravity assist from Jupiter, enabling a roughly 13-year cruise to reach Uranus in the mid-2040s. The last time any spacecraft visited Uranus was Voyager 2 in 1986, during a brief flyby.

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? Work on the Enceladus Orbilander would likely begin no earlier than fiscal year 2029. After arriving at its destination, potentially circa 2050, it would spend about a year and a half conducting investigations from orbit. It would then descend to the moon’s icy surface, where it would attempt to detect signs that life exists in the liquid ocean beneath. The Orbilander is anticipated to cost about $4.9 billion in fiscal year 2025 dollars.

Medium-Scale Missions and New Frontiers

Below the flagship tier, NASA runs two competitive mission programs: Discovery (small-class) and New Frontiers (medium-class). The survey recommended the cost cap for New Frontiers missions be raised to $1.65 billion in fiscal year 2025 dollars to reflect experience such as the Dragonfly mission to Titan under development.

For the New Frontiers 6 mission late this decade, the survey proposed concepts that include a mission to a Centaur family of icy bodies orbiting between Jupiter and Neptune; a sample return mission from Ceres, the largest body in the main asteroid belt; a comet sample return mission; a spacecraft to perform multiple flybys of Enceladus; a network of lunar landers to collect geophysical data; a Saturn probe; a Titan orbiter; and a mission to perform in situ studies of the atmosphere of Venus.

The Mars Life Explorer is worth examining separately. While Mars already has the Perseverance rover active, the survey committee saw a distinct scientific need for a mission specifically targeting habitability questions in Mars’s near-surface environment today, not millions of years ago. Mars polar ice deposits contain significant quantities of water ice, and there’s scientific argument that near-surface brines may create localized habitable niches even in the current Martian environment. Whether or not that argument holds up is an open scientific question, but the survey judged it worth investigating with a dedicated mission.

As of April 2026, no new Discovery or New Frontiers mission selections have been made in the current decadal period. The current missions in development, VERITAS and DAVINCI for Discovery and Dragonfly for New Frontiers, are remnants of the prior decadal period and have all experienced delays and budget growth. The next call for new mission proposals is not expected until late 2026, with selections likely to be made the following year.

Planetary Defense Enters the Conversation Formally

For the first time in the survey’s history, planetary defense received dedicated treatment as a chapter organized around the framework from the U.S. National Near-Earth Object Preparedness Strategy. The committee produced 42 findings and 11 recommendations covering detection, tracking, characterization, deflection, international cooperation, and emergency response planning.

The survey endorsed NEO Surveyor, a space-based infrared telescope designed to catalog near-Earth objects down to sizes that could cause regional destruction. After NEO Surveyor, the highest priority planetary defense demonstration mission should be a rapid-response, flyby reconnaissance mission targeted to a challenging near-Earth object representative of the population posing the highest probability of a destructive Earth impact, approximately 50 to 100 meters in diameter. The DART mission successfully altered the orbit of the moonlet Dimorphos in September 2022, demonstrating kinetic impactor deflection for the first time. The survey’s recommended follow-on would test characterization capabilities for short-warning scenarios.

The State of the Profession

The survey allocates substantial space to workforce issues, noting that the scientific enterprise produces nothing if it can’t attract, develop, and retain talent. Eight recommendations specifically address what the committee calls the “state of the profession.”

The committee applauded hard-earned progress, 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 and ethnicity. Recommendations include an evidence-gathering imperative, equity and accountability measures, and attention to graduate student support, postdoctoral research funding, and early-career stability. The underlying logic is that constraining the field’s talent pool by any mechanism, whether overt discrimination or structural barriers, directly limits the quality of science that gets done.

Budget Architecture and the Growing Gap

The survey offered two budget profiles. The “Level Program” assumes 2 percent annual growth in NASA’s Planetary Science Division budget from 2023 through 2032. The “Recommended Program” increases total decade spending by 17.5 percent above the Level Program.

In the first two years of the decadal period, NASA spent $1.04 billion less on planetary science than outlined in the decadal survey’s Level Program, and $1.27 billion less than outlined in the Recommended Program. NASA is on track to spend $5 billion below the Level Program and $11 billion below the Recommended Program over the 10-year decadal period.

The FY2026 appropriations cycle brought some relief but also a painful trade-off. Congress passed a budget of $24.44 billion for NASA, around 1.7% below enacted funding levels, and brought the Science Mission Directorate down only 1% to $7.25 billion. That outcome was far better than what the White House proposed, and it represented a near-complete victory for the Planetary Society‘s “Save NASA Science” campaign. The bill provides $2.5 billion for planetary science. However, the explanatory statement states that the bill does not support the existing Mars Sample Return program.

Mars Sample Return: The Survey’s Top Priority Falls

There’s no way to assess the decadal survey’s current standing without confronting what happened to Mars Sample Return. When the survey was published in April 2022, MSR was framed as the highest programmatic priority for NASA’s robotic planetary program. The Perseverance rover had recently begun collecting samples, and the scientific case was as strong as it had ever been. By April 2026, the program is effectively cancelled.

MSR had long pitted planetary scientists against each other, as fears grew that its ballooning cost, which rose to $11 billion in 2024, would consume far too much of NASA’s science budget. That led to repeated threats of cancellation from Congress, only for the program to survive in a more limited form while NASA reworked its plans. The agency’s final proposal for the mission, released in January 2025, would have brought its cost back down to $7 billion, closer to earlier estimates. But even that price tag was too high, with other NASA science missions struggling with cost overruns.

In May 2025, the Trump administration released its fiscal year 2026 budget proposal for NASA, in which they planned to cancel the MSR program on the American side. In January 2026, U.S. Congress confirmed that MSR will not be funded, thus the mission can be considered cancelled.

After the USA cancelled the sample return mission, ESA was considering repurposing its Earth Return Orbiter for a standalone one-way mission to Mars called ZefERO, possibly launching in 2032. However, in early 2026, ESA member states decided to cancel ERO and the agency began discussions with ERO’s prime contractor, Airbus Defence and Space, about reusing certain technologies developed for the mission.

The samples themselves aren’t going anywhere. Perseverance continues operating on Mars, and the cached tubes sitting at the Three Forks Sample Depot and aboard the rover remain intact. China aims to launch its Tianwen-3 mission to Mars in 2028 and bring samples to Earth by 2031, albeit with a much simpler mission that would collect samples from a single location. The prospect of China becoming the first nation to return samples from Mars while the United States abandons the effort is not a comfortable one for planetary scientists who spent decades building toward MSR.

This outcome is, in a narrow sense, consistent with the decadal survey’s own decision rules. The committee explicitly stated that MSR should be restructured or descoped if costs escalated beyond what the program could responsibly absorb. What the committee probably didn’t anticipate was a complete defunding rather than a managed restructuring.

The FY2027 Budget Proposal and What It Means

On April 3, 2026, the White House Office of Management and Budget released its fiscal year 2027 budget proposal for NASA. That proposal included $18.8 billion for NASA, a 23% reduction from what the agency received in a final fiscal year 2026 appropriations bill in January. The FY2027 budget request for NASA would cut the Science Mission Directorate by 47%, from $7.25 billion to $3.9 billion.

Congress rejected the FY2026 proposal and kept the agency funded at roughly the same appropriated level as FY2025. The FY2027 proposal is numerically identical to what OMB requested for FY2026 and was met with immediate, bipartisan pushback. Senate Appropriations Committee chair Sen. Susan Collins and Vice Chair Sen. Patty Murray both criticized the request overall, with Murray noting it contradicts the administration’s claims of shaping a “Golden Age of Innovation.”

The brief OMB summary stated the budget would “terminate over 40 low-priority missions.” The two examples it gives are at opposite ends of the spending spectrum: Mars Sample Return, a program planned to cost up to $11 billion, and SERVIR, a program to distribute Earth science data on which NASA spends $10 million annually. The Planetary Society described the proposal as threatening U.S. leadership in space science, while noting that Congress had already rejected essentially the same cuts once.

NASA Administrator Jared Isaacman, who was sworn in on December 18, 2025, has since outlined an ambitious vision for the agency: an accelerated cadence of human and robotic lunar activity, the initial elements of a permanent lunar base, and efforts to get the United States underway in space on nuclear propulsion as part of its longer-term Moon-to-Mars agenda. The FY2027 budget request concentrates resources in that exploration direction, while proposing a sharp reduction in NASA’s Science account, a shift that would weaken many of the research programs that underpin the agency’s broader scientific return.

Each cycle of proposed demolition and congressional rescue inflicts cumulative institutional damage on NASA, damage that is already degrading the agency’s ability to plan missions, retain talent, and hold together international partnerships. That assessment reflects the structural problem clearly: even when Congress ultimately restores funding, the annual ritual of existential budget threats prevents the kind of multi-year planning that complex missions require. You can’t design a spacecraft by committee in a continuing resolution.

The Human Exploration Dimension

The integration of science with human exploration is a theme the survey addressed with pointed language. NASA’s Artemis program aims to return astronauts to the Moon and establish a sustained presence there. Artemis II, carrying four crew members including Canadian astronaut Jeremy Hansen, launched on April 1, 2026, on a lunar flyby mission. The survey committee had stated that science requirements do not currently drive Artemis mission design and used emphasized language to assert that the program must support “breakthrough, decadal-level science.”

The report endorsed a mission concept called Endurance-A that would send a robotic rover to the Moon’s South Pole Aitken Basin on a commercial lander. The rover would travel 2,000 kilometers across the basin and collect 100 kilograms of samples. The South Pole-Aitken Basin is scientifically valuable because its deep crater floor likely exposes material from the lunar mantle, dating to the era when the Moon was partially molten.

The survey’s position on human exploration is measured rather than enthusiastic. It sees real scientific opportunity, particularly at the Moon, but is skeptical about vague commitments that don’t translate into specific, enforceable science requirements attached to mission hardware.

Science Across the Solar System

Beyond the flagship priorities, the survey mapped out active science questions spanning nearly every category of body in the solar system.

At Venus, the survey endorsed the two Discovery-class missions already in development: DAVINCI and VERITAS. Both missions address a planetary mystery: Venus and Earth began with similar compositions but arrived at radically different outcomes, and new evidence suggests Venus may be geologically active today and may have had habitable surface conditions as recently as one billion years ago.

At Mercury, volcanism played a critical role in shaping the surface, and permanently shadowed regions near Mercury’s poles hold abundant water ice. Recent missions revealed the surface and interior structure of the Moon in unprecedented detail, including newly discovered tectonic features and surface water ice in some permanently shadowed regions.

Among ocean worlds and dwarf planets, intermittent plumes of water vapor jet into space from Europa, and Enceladus is home to a potentially habitable water ocean. Pluto is unexpectedly geologically active, and brine deposits exist on the surface of Ceres. These findings collectively strengthened the scientific case for missions targeting icy body habitability, making the Enceladus Orbilander concept all the more compelling scientifically even as budget headwinds delay its development.

Where the Survey Stands as of April 2026

Three years into the decadal period, the picture is significantly more troubled than the survey’s authors would have hoped.

The cancellation of Mars Sample Return is the starkest departure from what the community recommended. The Perseverance samples, including the potentially significant Cheyava Falls rock core, sit on Mars with no funded path to retrieval. Whether a future administration or a future Congress reopens the question is ly uncertain. China’s Tianwen-3 program advancing toward a 2031 sample return creates competitive pressure that could eventually revive U.S. interest, but that’s speculative.

Europa Clipper, a flagship from the previous decadal, launched in October 2024 and is en route to Jupiter. That mission’s survival through the budget turbulence is real and meaningful. NEO Surveyor continues development. Some elements of the planetary defense priority are tracking reasonably well.

The Uranus mission remains the highest-priority new flagship, but no development funds have been committed. The optimal 2031-2032 launch window, which requires a Jupiter gravity assist, is not infinitely forgiving of delay. If funding trends continue, there will be a $5 to 11 billion shortfall in planetary science funding by 2032. These missing billions will reduce the rate of medium and small planetary missions, severely delay new flagship missions to Uranus and Enceladus, and severely constrain options for implementing Mars Sample Return. With MSR now cancelled, the concern about delay has become a concern about permanent loss for that specific priority.

The Influence the Document Actually Holds

There’s a tendency to treat the decadal survey as either a sacred document or an advisory exercise without consequence. The truth is somewhere between those extremes, but events since 2022 have tested the boundary. Historically, top-priority missions have eventually flown: New Horizons to Pluto, Cassini to Saturn, Perseverance and Europa Clipper all trace back to decadal recommendations. The mechanism through which those recommendations became hardware was slow, contentious, and subject to budget politics, but the track record was real.

The cancellation of Mars Sample Return represents the first time in the modern history of the decadal process that the stated highest overall priority has been defunded outright rather than delayed or restructured. Whether this is an anomaly produced by a specific convergence of cost overruns and political circumstances, or whether it signals something more lasting about the survey’s authority, will become clearer as the FY2027 appropriations process plays out.

The decadal provides a framework for all debates about funding priorities in NASA, the White House, and Congress. It serves as both sword and shield: a means to rally the community around new projects and investigations, and also to defend current priorities against budget cuts. Lawmakers and NASA take the decadal survey seriously, but they are not bound to it. That framing remains accurate. What’s changed is the cost of not being bound by it.

Summary

The Planetary Science and Astrobiology Decadal Survey 2023-2032 was published in April 2022 as the most structurally ambitious edition of the survey yet, organizing its scientific priorities around 12 broad questions, formally incorporating planetary defense, and presenting a clear flagship mission hierarchy anchored by Mars Sample Return, Uranus, and Enceladus. As of April 2026, the first and highest of those priorities is cancelled, the second has yet to receive development funding, and the federal budget environment for science remains deeply unstable following the White House’s FY2027 proposal to cut NASA’s Science Mission Directorate by 47%.

What makes the survey worth studying now is precisely the gap between what it recommended and what has transpired. The document’s scientific logic is intact. The case for an ice giant mission, for life detection at Enceladus, and for returning the Perseverance samples remains as strong as it was in 2022. The problem has never been the science. It’s been whether the institutions responsible for executing it can sustain the commitment over the multidecadal timescales that planetary exploration demands.

Appendix: Top 10 Questions Answered in This Article

What is the Planetary Science and Astrobiology Decadal Survey 2023-2032?

It is a report produced by the National Academies of Sciences, Engineering, and Medicine that identifies the most important scientific questions and mission priorities for planetary science and astrobiology across the decade from 2023 to 2032. Chartered by NASA’s Science Mission Directorate with support from the National Science Foundation, it was released on April 19, 2022 under the title Origins, Worlds, and Life: A Decadal Strategy for Planetary Science and Astrobiology 2023-2032. The report runs over 780 pages and was assembled over approximately two years.

What happened to Mars Sample Return, the survey’s top priority?

Mars Sample Return was effectively cancelled in January 2026 when Congress passed the FY2026 spending bill explicitly stating it did not support the existing MSR program. The mission’s costs had ballooned to an estimated $11 billion, prompting the Trump administration to propose cancellation in its May 2025 budget request, which Congress then confirmed. The European Space Agency subsequently cancelled its Earth Return Orbiter, its contribution to the joint effort, in early 2026. The Perseverance rover’s cached samples remain on Mars with no funded retrieval mission.

What is the top new flagship mission recommended in the survey?

The Uranus Orbiter and Probe is the highest-priority new flagship mission, recommended for initiation during the 2023-2032 decade. It would deliver an atmospheric probe and conduct a multi-year orbital tour of the ice giant, with optimal launch windows in 2031 or 2032 enabling a roughly 13-year cruise to arrive in the mid-2040s. The mission is estimated to cost approximately $4.2 billion in fiscal year 2025 dollars and was identified as requiring no new technologies, making it the lowest-risk flagship concept considered. As of April 2026, no development funding has been committed.

What is the Enceladus Orbilander mission?

The Enceladus Orbilander is the second-priority new flagship mission. It would travel to Saturn’s moon Enceladus, spend roughly 18 months in orbit sampling active water vapor plumes erupting from a subsurface ocean, then land on the icy surface for a two-year mission searching for chemical signatures of life including amino acids, lipids, and cell-like morphologies. The mission’s estimated cost is approximately $4.9 billion in fiscal year 2025 dollars, with development not expected to begin before fiscal year 2029 and arrival at Enceladus potentially around 2050.

What does the FY2027 White House budget proposal mean for NASA science?

Released on April 3, 2026, the FY2027 White House budget proposal would cut NASA’s total budget by 23% to $18.8 billion and slash the Science Mission Directorate by 47%, from $7.25 billion to $3.9 billion. It proposes terminating over 40 missions the administration labels low-priority, while fully funding human exploration programs including Artemis. Congress rejected an identical FY2026 proposal and approved $24.44 billion for NASA instead; early signals suggest a similar congressional rejection is likely for FY2027, though the annual cycle of proposed cuts and rescues inflicts ongoing institutional damage.

How does the decadal survey organize its scientific questions?

Rather than structuring priorities around specific planets, the 2023-2032 survey organized 12 priority science questions into three overarching themes: Origins, covering how the solar system and its components formed; Worlds and Processes, addressing how planetary bodies evolved over time; and Life and Habitability, asking where life-supporting conditions exist and whether life is present beyond Earth. This thematic approach was a departure from earlier decadal surveys and was intended to evaluate missions based on broad scientific merit.

Is the decadal survey legally binding on NASA?

No, the decadal survey carries no legal authority. NASA and Congress are not bound by its recommendations, and budgetary pressures or shifting political priorities have historically prevented some recommended missions from being funded. However, the survey’s top priorities have a strong track record of eventually flying: New Horizons, Cassini, Perseverance, and Europa Clipper all trace back to decadal recommendations. The cancellation of Mars Sample Return in January 2026 represents the first instance of the survey’s stated highest overall priority being defunded outright rather than delayed.

What did the decadal survey say about planetary defense for the first time?

The 2023-2032 survey was the first to include planetary defense as a formal dedicated chapter, producing 42 findings and 11 recommendations covering NEO detection, characterization, deflection demonstration, international cooperation, and emergency response. It endorsed NEO Surveyor, a space-based infrared telescope for finding hazardous near-Earth objects, and recommended a rapid-response flyby mission to characterize a 50-to-100 meter object as the next planetary defense demonstration after DART, which successfully altered the orbit of Dimorphos in September 2022.

How large is the funding gap between the survey’s recommendations and actual NASA spending?

In the first two years of the decadal period, NASA spent approximately $1.04 billion less on planetary science than the survey’s Level Program called for, and $1.27 billion less than the Recommended Program. If current trends continue, the total cumulative shortfall by 2032 could reach between $5 billion and $11 billion. That level of underfunding delays the Uranus mission, prevents the start of Enceladus development, and now coincides with the outright cancellation of Mars Sample Return.

What role does human exploration play in the decadal survey’s recommendations?

The survey addressed human exploration mainly in the context of the Artemis lunar program, stating that science requirements do not currently drive Artemis mission design and insisting this must change. It endorsed the Endurance-A robotic rover concept, which would traverse 2,000 kilometers across the South Pole-Aitken Basin collecting approximately 100 kilograms of samples for later retrieval by astronauts. Artemis II launched on April 1, 2026, carrying four crew members including Canadian astronaut Jeremy Hansen on a lunar flyby, representing the first crewed mission to travel beyond low Earth orbit since Apollo 17 in 1972.