Some of the greatest mysteries of the universe, such as the possibility of life on Mars or Venus, may never be solved because of Donald Trump’s proposed “extinction-level” cuts to Nasa spending, scientists are warning.
The Trump administration revealed last month its plan to slash the space agency’s overall budget by 24% to $18.8bn, the lowest figure since 2015. Space and Earth science missions would bear the brunt of the cutbacks, losing more than 53% of what was allocated to them in 2024.
If the budget is approved by Congress, opponents say, longstanding Nasa labs will close, deep-space missions, including many already under way, will be abandoned, and a new generation of exploration and discovery will never reach the launchpad.
Two of the most notable casualties will be the Mars sample return mission, which had been in doubt on cost grounds for a while, and the Davinci+ and Veritas projects. The latter two were announced during the Biden administration and planned for the early 2030s; they would have sent Nasa back to study Venus for the first time since 1989.
Advocates are highlighting the future discoveries that will not be made, as much as the loss of initiatives that were extensively planned years ago, as they ramp up their campaign to persuade Washington lawmakers to defy the president and preserve or even expand Nasa’s funding.
“An extinction-level event is when something like an asteroid hits Earth and life that has been otherwise perfectly well-functioning, healthy ecosystems that have been balanced and functioning, are wiped out in large numbers. That’s functionally what this budget is,” said Casey Dreier, chief of space policy at the Planetary Society, which is rallying Congress members to oppose the budget.
“Projects that are functioning, that are on budget and on time, that are already paid for and returning good science, would be decimated. You’d see missions turned off mid-flight, extended missions put into hibernation or left to tumble in space. You’d see projects that could launch next year canceled summarily, and hundreds if not thousands of scientists and engineers and others laid off due to loss of research money and technology investments.
“What this does is turn off the spigot of discovery, the investments we’re making now that are going to pay off in five years, 10 years, maybe 20 years, that may fundamentally reshape our understanding of our place in the cosmos, our origins.
“Is Mars habitable for life? Is Venus? How many Earth-like planets are there? Those types of questions will not be answered because we just decided not to answer them. We’re abandoning literally decades of debate and discussion and justification.”
As well as the planetary missions, a significant number of other science projects that have been in the works for years face the axe. While the Trump administration proposes to slash Nasa’s overall budget, it also seeks to prioritize and grant extra funding to crewed spaceflight – particularly the first human missions to Mars, a stated focus of the president and his as-yet unconfirmed pick for Nasa administrator, the entrepreneur Jared Isaacman.
The advocates say a particularly acute loss to un-crewed science would be the $3.9bn Nancy Grace Roman space telescope, a successor to the James Webb and Hubble telescopes that have produced stunning images and unexpected insight into the origins of the universe.
If the telescope, which is nearing completion and set for launch before May 2027, is scrapped, 200,000 possible planets beyond our solar system may never be discovered, more than one billion galaxies might never be surveyed, and secrets of black holes, dark matter and dark energy may never be uncovered, the Planetary Society said.
Billions of dollars have already been spent on it, and killing it now would be “nuts”, astrophysicist David Spergel told Scientific American last month.
Other experts lament the distancing of the Trump administration from science, and believe it will allow other nations to catch or eclipse US leadership in space.
“What’s happening now, and that’s beyond Nasa, is this general atmosphere of: ‘No, science is not important to us as much as it used to be,’” said Ehud Behar, a high-energy astrophysicist at Technion – Israel Institute of Technology, and a former Nasa researcher.
“Is the US going to be left behind? It might take time, this is not going to happen tomorrow, but China has enough people, they have enough scientists. If they are going to invest much more in science and technology development, they’re going to be more competitive, and they’re going to achieve things within five to 10 years that today maybe only Nasa can achieve.”
Behar also fears a “brain drain” of Nasa’s top talent.
“There are a lot of good people in these agencies, and they’ve made a living of being innovative on a budget that was always limited. If somebody thinks that you walk into Nasa and you have boxes of dollars falling on your head, that’s not the case when you want to do a mission,” he said.
“Even in the best years, you never had enough money to do everything you wanted. So these people are pretty well-trained to find ways with less funding to get the job done. You can count on these people as long as you hold on to them.
“Hanging on to your best people is one of the main challenges when you have to cut the budget.”
Dreier said there had been “productive” conversations with congressional politicians on both sides of the aisle, and that a number of Republicans and Democrats were pushing for an increase to Nasa’s science budget in place of the cuts.
The argument to them, he said, is simple: why throw away so much of what has already been bought and paid for?
“It’s just like we’re giving up and turning away. Instead of looking up, we’re turning down and inwards,” he said.
“This is a budget of retrenchment, this is a budget of retreat. It’s basically the equivalent of hunching over a cellphone and swiping through pictures of the Grand Canyon while you’re sitting at the edge of it in reality and not even bothering to look.”