Since Donald Trump re-entered the White House in January 2025, his administration has made sweeping funding cuts across dozens of federal agencies. NASA is no exception – with the 2026 budget set to reduce the agency’s funding by up to 24.3 per cent.
That equates to a fiscal drop from $24.8bn (£18.4bn) allocated by Congress for 2025 to $18.8bn (£13.9bn) in 2026 – the most meagre NASA budget since 2015.
The president’s request does not carry the weight of law until it’s been through Congress, where its language will be scrutinised, debated and amended in the coming months.
However, its sparseness spotlights several key priorities Trump has shown across his two presidential terms.
A focus on human spaceflight
During Trump’s first administration from 2017 to 2021, NASA’s budget rose from $19.5bn (£15.5bn) to $23.3bn (£18.5bn) – about 0.48 per cent of federal expenditure.
Trump re-established the long-defunct National Space Council to steer US space policy and created the US Space Force, bringing together national security space assets under America’s newest military branch.
He demonstrated a focus on human spaceflight, initiating NASA’s Artemis programme to return humans to the Moon, originally by 2024.
That date proved overly ambitious, but Artemis II is still on track to take humans back to the vicinity of the Moon in 2026. If all goes well, Artemis III will set down on the Moon’s surface in the years after.
Near the end of his first term, Trump unveiled a National Space Policy that formalised commitments to return to the Moon and send astronauts to Mars. And the policy streamlined regulatory frameworks permitting the private sector more access to space.
As Trump began his second term, this support for human spaceflight and exploration continued.
When the White House unveiled its NASA budget in April this year, the focus was getting Americans back to the Moon “before China”, a nation that has made no secret of its grandiose ambitions to establish a lunar base in the 2030s.
During Trump’s first administration from 2017 to 2021, NASA’s budget rose from $19.5bn (£15.5bn) to $23.3bn (£18.5bn) – about 0.48 per cent of federal expenditure.
“This proposal includes investments to simultaneously pursue exploration of the Moon and Mars, while still prioritising critical science and technology research,” says acting NASA administrator Janet Petro, adding that the agency will “continue making progress toward achieving the impossible”.
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Projects at risk due to slashed budgets
But it may prove impossible (or at least painfully difficult) for NASA to achieve its goals as the budget also seeks to “streamline the agency’s workforce”, making cuts to many support services such as IT and maintenance.
The budget wants to cancel the “grossly expensive and delayed” Space Launch System (SLS) rocket and Orion crew capsule. These were designed for long distance space travel and would be used in the Artemis missions.
The budget proposes replacing them “with more cost-effective commercial systems” for “more ambitious subsequent lunar missions.”
According to the White House, the SLS is 140 per cent over-budget and costs $4bn (£3.2bn) per launch.
The SLS rocket flew the unmanned Artemis I mission in 2022 but if Trump’s budget goes ahead, it will fly only twice more – launching Artemis II astronauts Reid Wiseman, Victor Glover, Christina Koch and Jeremy Hansen around the Moon in 2026, then sending Artemis III to land humans on the lunar surface in mid-2027.
Cancelling the SLS and Orion, which Trump’s budget calls a “legacy human exploration system”, would save $879m (£698.5m).
However, US lawmakers have expressed vocal disquiet about scrapping a programme that (while eye-wateringly expensive) has taken a decade to bring to flight readiness and whose termination might cede ground to China.
That cold reality is not lost on Texas senator Ted Cruz. “I am hard-pressed to think of a more catastrophic mistake,” Cruz told the Senate at a hearing in April, “than saying to Communist China: the Moon is yours!”
Another specific project the budget seeks to terminate is the lunar Gateway, a new space station that would permanently orbit the Moon. The hardware for this is already being built in the US, Europe, Canada and Japan.
Although it could be repurposed for other missions, its cancellation risks alienating international partners that NASA has courted for decades.
No more science for NASA?
The budget also threatens deep cuts to NASA’s Earth and space science programmes – the former by $1.16bn (£921.7m), the latter by $2.65bn (£2.1bn) – a move The Planetary Society has criticised as “a historic step backward”.
“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.”
The budget would terminate “multiple, unaffordable missions”, including the long-delayed Mars Sample Return (MSR) mission, which it calls “unaffordable”.
The mission would seek to return rock and soil samples already taken by the Perseverance rover currently exploring Mars, with the aim of answering key questions about Mars’s past – including whether it might have once been habitable.
But last year, NASA admitted that the cost of the mission to return the samples had swollen from $7bn (£5.6bn) to $11bn (£8.7bn), while the date had slid from 2033 to 2040 at the earliest.
Instead, the budget suggests the MSR’s goals “would be achieved by human missions to Mars”, backing up the promise of “launching American astronauts to plant the Stars and Stripes on the planet Mars” that Trump made in his Inaugural Address.
But with China planning its own Mars sample return mission as soon as 2028, there remains a strong likelihood of Congressional pushback on the MSR’s cancellation.
In the Earth science arena, the budget took aim at a variety of Earth-monitoring satellites, including many related to tracking climate change.
It would rework NASA’s upcoming Landsat Next, a trio of spacecraft due to launch in 2031 that would monitor the health of Earth’s dynamic and rapidly changing landscapes.
Meanwhile, several climate satellites and instruments already in operation – such as the Orbiting Carbon Observatory, Deep Space Climate Observatory, and the Terra, Aqua and Aura satellites – would be shut down, and no longer operated, despite still being in full working order.
Another ‘at-risk’ mission is the Nancy Grace Roman Space Telescope, due to be launched in 2026-2027 to search for planets beyond our Solar System and investigate the evolution of the Universe.
Set to be the agency’s next big telescope, its observations would investigate the nature of dark matter, help to lift the veil on dark energy, and answer some of our most pressing questions about the Universe.
Though Roman’s cost has climbed from an initial $2bn (£1.6bn) to over $3.2bn (£2.5bn), the telescope is built and almost ready for launch, with 90 per cent of its projected costs already spent.
While the budget doesn’t seek to cancel Roman, it would cut its development funding by $244m (£193.9m), jeopardising the final steps needed to take the telescope to orbit.
As the budget still needs to be ratified by Congress to take effect, it remains to be seen how many of the changes will come into effect. Will the cuts be devastating to science or herald a new age of human exploration?
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