NASA is facing historic budgetary threats. The fiscal year 2026 and 2027 budget requests each proposed cutting NASA’s Science Mission Directorate by nearly 50%. More than 50 science missions are facing termination. Efforts like Mars Sample Return, missions to Venus, and the Geospace Dynamics Constellation have been canceled or delayed given the budgetary constraints, and there has been fierce criticism over cost overruns and schedule slips.

In that context, NASA is turning to cheaper and more tightly controlled projects in an effort to return scientific discoveries more quickly and at a lower cost. The most visible implementation is the Commercial Lunar Payload Services (CLPS) program, started in 2018, which buys rides for NASA instruments aboard commercially built lunar landers. In the last two years, the agency has also begun a run of internally directed science missions chosen without competition, including the SkyFall helicopters and Aeolus instruments bound for Mars, and the PROMISE rover to the Moon.

Meanwhile, the competitive programs that produce some of NASA’s most celebrated missions have stalled. Discovery-class missions, meant to launch every two years, now face a seven-year gap between Psyche’s launch in 2023 and DAVINCI’s expected launch in 2030. The New Frontiers program, which gave us missions like New Horizons at Pluto and Juno at Jupiter, was meant to be competed twice each decade, but it will see at least a full 10-year gap between the selection of Dragonfly in 2019 and its next mission.

An untested premise behind these choices is that smaller and cheaper missions can substitute for the science of larger ones at a reduced cost.

Multibillion-dollar decisions of this magnitude deserve evidence, and until now, the data existed only in scattered budget documents and inconsistent publication archives. So, as a first step, we assembled a way to track and compare science output.

The Science Mission Impact study

Nine years ago, the National Academies told NASA to build a publicly accessible database of NASA missions, their costs, and their impacts on science and society. Such a database would track the differing value offered by different mission types. For example, if NASA decides it wants more transformative discoveries per dollar, or science results faster, the database would provide the evidence to decide which types of missions to fund.

NASA has not yet produced such a database. So, today we are publishing ours, which covers some of the key elements recommended by the National Academies.

We compiled every NASA-led scientific spacecraft launched from 1980 through 2024, across all five science divisions, with life-cycle costs adjusted for inflation to 2025 dollars. For each mission, we gathered the peer-reviewed papers that discuss the mission and its data, and counted how often other scientists cited them.

We gathered peer-reviewed publications and citation counts from NASA’s SciX Digital Library, which collects publication references for the agency’s primary areas of scientific research. Peer-reviewed scientific articles are a formal and traceable way that scientists share and test new ideas. Citation counts gauge the influence of those ideas on subsequent efforts, and highly cited publications reflect society-improving discoveries. For example, a highly cited paper describing how the NEOWISE spacecraft measured near-Earth asteroids defines, in-part, how the United States tracks progress toward its congressional mandate to characterize impact threats. More broadly, publications across Earth Science, Planetary Science, Heliophysics, and Astrophysics missions each trace the development and application of digital cameras. The compact, low-power cameras developed for spacecraft are now the basis for over 7 billion sensors manufactured each year in a $25 billion market.

What we found

Mid-cost missions tend to return excellent scientific impact per dollar. In three of the four science divisions with enough missions to compare, missions costing between $150 million and $1 billion (e.g., Discovery, Explorer, and New Frontiers classes) matched or beat both cheaper and more expensive missions in science per dollar.

Cheaper does not always mean faster science. Large flagship missions take a long time to construct, but many very low-cost missions produce no high-impact science at all, and those that do can take as long as mid-cost missions to get there.

Cheap missions fail far more often. Of missions below $150 million in our study, 30% failed. Among all more expensive missions, 8% did. For the small-mission class as a whole to be as efficient as larger missions, each surviving small mission would need to be about a third more productive on average. They are not.

Competed missions also tend to return excellent scientific impact per dollar. Among mid-cost missions, the most scientifically productive ones have tended to be led by independent scientists who proposed the mission in an open NASA competition, rather than directed from within NASA.

Commercial lunar landers are trailing in scientific publications. The four CLPS missions flown so far have each produced fewer papers than comparable NASA-led science missions as measured from the start of operations.

What our study does not say

Nothing here argues for fully abandoning either small or large missions. But if the goal is to ensure high-impact science more quickly, top-down small missions have historically not provided that outcome.

Small missions remain very much worth doing for other reasons. They train people who go on to lead in the space industry, they prove new technology, and some of them return excellent science. Flagships are worth doing too. They make discoveries once thought impossible to achieve, and they sustain entire communities of scientists for decades. Both ends of the range, and all missions in between, depend on one another.

See for yourself

The dashboard lets you explore all 143 missions by cost, failure rate, and time to first result, with a page for each of NASA’s five science divisions. Our full methodology is documented, and the entire dataset is available to download. A peer-reviewed article presenting the complete analysis is forthcoming.

These findings relate to decisions being made right now, in NASA’s budget request and the appropriations bills that follow it, about which mission lines get started and which go another year without a competition.