On July 21—the 56th anniversary of the Apollo 11 moon walk—287 current or former NASA employees signed or endorsed a strongly worded open letter to NASA acting administrator Sean Duffy. The letter objects to the space agency’s draconian budget and personnel cuts proposed by the White House. Of those signatories, 131 openly wrote their names. The remaining 156, concerned for their jobs, lent their support anonymously. [time-brightcove not-tgx=”true”]And then, too, there were 17 more names added at the bottom of the letter–belonging to 17 people who didn’t have a say in whether their names were used or not. They included Gus Grissom, Ed White, Judith Resnik, Christa McAuliffe, Willie McCool, Kalpana Chawla and the other explorers who lost their lives in the Apollo 1 fire, the Challenger explosion, and the Columbia disintegration. The names were there for more than sentiment; they were there as pointed reminders of what can go wrong in the white-knuckle business of space—what too often does go wrong—when corners are cut, funding is slashed, and work forces are reduced in pursuit of short term budgetary gains.“Safety is being compromised in every way,” says three time space veteran and retired NASA astronaut Cady Coleman, a signatory of the letter, in a conversation with TIME. “We are courting another space disaster.”Coleman feels that danger more acutely than most. During the Columbia crew’s training, she worked as their capsule communicator—or capcom—the sole voice between mission control and the astronauts. By the time the crew actually went to space, she was finishing up a rotation in Antarctica, assisting in NASA’s meteor collection program. She was on her way home, staying with friends in New Zealand, when the terrible word from space came down. “My friend called and said ‘Cady, we lost Columbia. I remember thinking, ‘How could we lose them?’ It was definitely a hard journey home.”Read more: The True Cost of Trump’s Cuts to NOAA and NASAIt’s not just loss of crew safety that the 287 signatories of the open letter—dubbed The NASA Voyager Declaration—are protesting. There’s the scrapping of projects like the Mars Sample Return Mission, which is already underway, with the Perseverance rover caching samples on the Martian surface for later return to Earth. There is the premature cancellation of the Space Launch System (SLS) moon rocket, and the Orion crew capsule, NASA’s only crewed ride back to the moon. There is the proposed 50% cut to NASA space science missions, including the brand new Nancy Grace Roman Space Telescope, the all-but completed $4 billion observatory set for launch in May 2027—which now might be consigned to simply idling in its clean room in Greenbelt, Maryland. Overall, NASA faces a 24% budget cut, from $24.8 billion in 2025 to $18.8 billion in 2026—its lowest funding level since 2015.“We dissent to the closing out of missions for which Congress has appropriated funding because it represents a permanent loss of capability to the United States both in space and on earth,” wrote the signatories. “We dissent to implementing indiscriminate cuts to NASA science and aeronautics research because this will leave the American people without the unique public good that NASA provides.”And there’s more. There’s the loss of intellectual capital that comes when highly trained civil servant engineers are either sacked out of hand or pack their bags and go, taking their talents to the less political private sector, where job security is greater and compensation is higher.“Thousands of NASA civil servant employees have already been terminated, resigned or retired early, taking with them highly specialized, irreplaceable knowledge crucial to carrying out NASA’s mission,” reads the letter.Says retired NASA astronaut Terry Virts, now a candidate for a U.S. Senate Seat in the Democratic primary in Texas: “These Trump personnel cuts to space exploration are undermining future generations of engineers and scientists as well as those mid-career employees who are at the height of their competency and productivity. It’s as if a farmer is destroying his seed corn as well as his crops in the field. The damage that this administration is causing will last for a generation.”Read more: What Trump’s Proposed NASA Budget Cuts Really Mean for the Space AgencyThe number of anonymous signatories to the Voyager Declaration letter is perhaps a sign of wariness of an administration that is famously intolerant of—and punitive toward—perceived disloyalty. But NASA employees at least come with a modicum of institutional security. After the Columbia disaster in 2003—an accident that was partly the result of lower-echelon employees fearing for their jobs if they spoke out of turn about safety lapses they observed—NASA established its Technical Authority protocol, which provides protection for employees to report anomalies or dangerous corner-cutting to superiors outside their direct chain of commandThe signatories also cite an official NASA policy directive, similarly ensuring support for speaking truth to power. “NASA supports full and open discussion of issues of any nature … including alternative and divergent views. Diverse views are to be fostered and respected in an environment of integrity and trust with no suppression or retribution.” The catch: The effective date of the rule was January 29, 2020, and the expiration January 29, 2025.Will the letter have any effect at all? Recent history doesn’t portend good things. In June, employees at the National Institutes of Health penned a similar open letter, which yielded little result. Earlier this month, employees at the Environmental Protection Agency, filed their own letter, with even worse results; 140 of them were placed on administrative leave.But NASA backers are not giving up hope. For one thing, the steep budget cuts the White House proposes still have to be approved by Congress, and with thousands of NASA jobs in dozens of Congressional districts, lawmakers are disinclined to take money out of their constituents’ pockets. The SLS and Orion were spared in just that way in 2010, when then President Barack Obama proposed scrapping them and Capitol Hill said no dice.And then too there is the less tangible, more lyrical side of space travel that may redound in NASA’s favor. “I’m an optimist,” says Coleman. “There’s something about space that’s compelling. There are things out there we don’t know about. I think that a letter about space is going to reach people. I think that people are going to understand that if we’re saying this about space, we’re saying it about microbiology, about sustainability too.”A single open letter may not be enough to change national space policy, but millions of voices expressing their support for it, just may.