Trying to understand Freedom

In March of 2026, NASA Administrator Jared Isaacman announced a new mission to Mars, a $2.1 billion nuclear electric rocket called SR-1 Freedom. The rocket is supposed to depart for Mars in late 2028, carrying a cargo of three miniature helicopters.

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The announcement was part of a broader basket of initiatives called Ignition. NASA’s new Administrator had peered into President Trump’s soul and discerned the outlines of a space policy, which included a nuclear rocket and a moon base. He had also peered into the NASA budget and perceived that these projects were somehow already funded, though no one else has been able to see what he saw.

Let’s talk a bit about the rocket.

Electric rockets are the Geo Metros of space travel, fuel efficient but painfully slow to accelerate. They work by ionizing and accelerating atoms of gas through a metal grid or plasma at very high speed (tens of kilometers/second). Electric propulsion comes in two broad flavors: solar electric rockets draw their power from big sail-like banks of solar panels, while nuclear electric rockets get it from a fission reactor about the size of a pony keg.

Besides the size advantage, nuclear power has the nice property that it does not degrade over time, diminish with distance from the Sun, or go away if you duck behind the shadow of a planet. A small, space-rated nuclear reactor also makes an excellent power source for surface missions to the Moon or beyond, although that application requires an engineering demo of its own. But launching nuclear reactors into space is contentious, and so NASA has never been allowed to try it before.

The design for SR-1 Freedom puts the reactor at one end of a long stick. Heat pipes connect the reactor to a turbine that generates about 20 kilowatts of electricity, or enough to power a cul-de-sac in the suburbs. At the other end of the stick is something called the Power and Propulsion Element, a box with a big bottle of xenon propellant and seven ion engines on it, that looks an awful lot like a restaurant stove. The Power and Propulsion Element is a key component of Gateway, the near-lunar space station that no one at NASA headquarters has ever been able to explain or defund. Now this piece of Gateway is being sent to Mars, like the Ring being sent to Mordor, to make sure it can never come back.

Behind the reactor there is a conical radiation shield (to prevent the reactor from frying everything around it) and a large area of radiator panels to get rid of heat from the turbine. There may or may not be a pair of vast solar arrays, big enough to power the spaceship in their own right. These are not really needed for the mission, but they come for free with the Power and Propulsion Element, so why not.

Tucked away somewhere in the back of the spacecraft is an aeroshell with a cargo of three small helicopters, loosely based on the Ingenuity helicopter that flew with Perseverance. The main difference from Ingenuity is that these helicopters are slightly heavier, carry a rudimentary radar set, and can operate independently of any rover, talking directly with satellites in space. Unlike Ingenuity, which launched from the ground, they are supposed to deploy in midair.

The mission looks like this: The spacecraft launches on a Falcon Heavy rocket, which sets it on a course for Mars. The boom, radiators, and solar panels all unfold and lock into place. Then, two days after departure, the reactor powers on and begins accelerating the spacecraft. The word ‘accelerating’ here is coming it a bit high; the thrusters on this bad boy have a combined thrust of just over a newton, or about the weight of a stick of butter. Picture a housecat leaning against a semi truck and you have an accurate sense of the forces in play on SR-1 Freedom.

It takes the best part of a year for this mighty rocket to drift its way to Mars. Once it gets there, it can’t really slow down—the cat would have to lean against the other end of the truck—so it flies by and encounters the planet again 300 days later. At some point in this cosmic ballet the entry capsule carrying the little helicopters detaches from the rocket, enters the Martian atmosphere, and releases them at low altitude to go exploring. What happens to the mother ship after that is unclear; it can keep flying past Mars or go fly past something else.

As you can see, the mission is really an engineering demo. The main thing NASA wants to learn is how long a reactor and turbine can stay powered on in deep space. Ideally, they would like to put a test reactor on the Moon, where the nights are two weeks long and solar power is infeasible. But NASA has no way to land anything large on the Moon right now and has to settle for testing a rocket. And once you’re flying a nuclear electric rocket in space, you might as well give it a little something to do, and send it somewhere nice.

The collective reaction to SR-1 Freedom from Mars obsessives has been bemusement. Propulsion is one of the few Mars problems that is mostly solved, and tiny helicopters are probably the last kind of probe scientists want to be sending to the planet right now. What Mars scientists dream about at night is sample return. Right this minute there are a dozen or so sealed containers lying around Jezero Crater that they are desperate to examine in Earth laboratories. Absent that, they would love to at least be able to drill under the Martian surface, particularly in areas that have accessible deposits of ice, to search for signs of groundwater or relic life.

But the Administrator wants to do flashy things that make the President happy. And so SR1-Freedom bears all the hallmarks of an Isaacman project:

• It’s assembled LEGO-style from whatever parts happened to be available in the bin (in this case, a chunk of Gateway, a helicopter design for Mars Sample Return, and a Department of Energy research reactor).
• The schedule is derived by working backward from the President’s term of office.
• The mission is designed around whatever can be thrown together in that time.
• Everything is Frankenfunded by raiding unsuspecting corners of the NASA budget.

It’s that last piece that spells trouble for NASA science. Isaacman claims that the rocket part of SR-1 Freedom is fully funded through occult budget magick involving Gateway, but the piece with the helicopters, called Skyfall, is not. It has to be paid for out of NASA’s science budget—the same budget Trump is right now trying to cut by 50%.

The way planetary science traditionally works at NASA is that there is a big decadal survey that assigns priorities, a rough consensus of how the funding pie for science missions should be cut over the next ten years. In theory, each decade sees one Flagship mission at the ~$5 billion level, two New Frontiers missions at the $1B level, and a handful of Discovery missions capped at $500M. There are also collaborations with foreign space agencies, especially Japan and Europe. This mechanism for setting priorities is fraying but valuable. It exists to prevent destructive infighting among scientists, and to avoid wasting money and launch opportunities on boondoggles that happen to catch the eye of an influential politician.

Except that now, Administrator Isaacman has short-circuited the process and put his own boondoggle in front of most influential politician of all. And while SR1-Freedom purports to be a cheap technology demo, it has every likelihood of turning into a nuclear money bonfire, because its current schedule and budget are simply infeasible.

Everyone familiar with aerospace understands the prospects of SR-1 Freedom coming in on budget and on schedule are nil. Remember that NASA is an agency that went four years over schedule and $2 billion over budget just trying to build a launch tower. The idea that they could get a new nuclear propulsion design and custom lander flying by 2028, even if they ignore all the permitting and safety commitments that come with launching a nuclear payload, beggars belief. And the idea that a fleet of Martian helicopters needing a new class of entry vehicle can be developed on a rush basis for less than the entire Mars budget is just delusional.

The first chunk of money for Skyfall will come out of the $110 million budget line for future Mars mission development, eliminating the agency’s ability to plan the next generation of Mars probes. Once that money runs out, the only place to get more will be the operating budget of ongoing Mars missions (Curiosity, MRO, Perseverance). After that, the axe would have to fall on future exploration missions like Dragonfly.

Isaacman has already shown that he’s willing to kneecap Mars science in support of high-profile stunts. In June, he floated a plan to convert the engineering testbeds for Curiosity and Perseverance into a lunar rover called Promise. The engineering duplicates for the Mars rovers live on Earth and are vital to mission planning and troubleshooting—you need to try things out on the backyard rovers first, to make sure you don’t brick the real ones on Mars. Even worse, the lunar Frankenrover would use up the only spare radioisotope generator in NASA’s inventory, stripping it from any potential future mission to Mars or the outer solar system.

But Isaacman wants fast and visible results on the moon, no matter what damage that does to NASA’s broader goals.

I don’t want to create the impression with this post that nuclear electric rockets are bad. They would be a terrific piece of technology for sending missions to the outer solar system, where solar irradiance is a tiny fraction of what it is near Earth. Nuclear electric vehicles are capable of operating for years at a high power level, which means they can carry powerful radars and antennas that are off-limits to today’s power-constrained probes. And once at Jupiter, Saturn, or Uranus, they could visit moon after moon, their low thrust compensated by incredible longevity and fuel efficiency.

But these are precisely the kinds of missions that Isaacman’s NASA is foreclosing on to pay for this stunt. Once the schedule starts to slip, this program is going to bleed dry every program on the science side of the NASA ledger, including the only missions that could possibly make use of it.

During his tenure at NASA, Isaacman has been pursuing a fourfold strategy:

1. In every public communication, position the President as the savior of American space flight.
2. Create a sense of urgency predicated on a rivalry with China. This dovetails with #1, since Trump has two years left in office and is uninterested in anything that happens later.
3. Insist that NASA has more than enough money already.
4. Tweet a lot and give people rides in his jet fighter.

The strategy is clearly working. The President is happy, he’s tweeting that America should own the moon, he puts a model of SR-1 on his desk for photo shoots. And Isaacman has gotten glowing coverage in the press for bringing dynamism and energy to his agency. But what we’re seeing are the most valuable parts of American leadership in space exploration being strip-mined to create an illusion of forward momentum. And instead of asserting American leadership in space, Trump and Isaacman are poised to give it away.

Today NASA is on the cusp of finding evidence of past life on Mars. The discoveries made in the past few years by Perseverance and Curiosity are hard to explain without invoking ancient microbial life. But the only way to know for sure is to bring samples to examine back to Earth. And the first country to bring samples back from Mars is not going to be the United States, but China. The 2028 Tianwen sample return mission is scheduled to return samples from Mars in 2031. In trying to drum up a new space race with China on the Moon, Isaacman is forfeiting the real one taking place on Mars, ceding a chance to make the greatest discovery in the history of science to a geopolitical rival.

A year ago, things looked rosy for Mars exploration. NASA had recently announced the discovery of complex organic molecules—potential biosignatures—at Gale Crater, along with strong circumstantial evidence for ancient microbial life in mudstones at Cheyava Falls. Mars Sample Return was flailing, but looked like it might be revitalized with creative ideas from private industry. SpaceX was planning to send five Starships to Mars in the 2026 launch window, followed by twenty more in 2028. That meant a US company was about to solve the hardest problem in Mars exploration—how to land large payloads on the surface—at no cost to the taxpayer.

But today, oh, how the turns have tabled. Early this year, SpaceX shifted their focus away from Mars to the Moon, part of a broader pivot to orbital AI, and all the promised Starship landings on Mars evaporated. Mars Sample Return, the heart of NASA’s Mars exploration program, is dead. For the first time in decades, the agency has no landed science mission in the works for Mars, either in the planning stage or under construction. And now the development budget for planning future missions is gone, spent on a makework mission for a technology that would only be useful to the very science programs it is cannibalizing.

At this writing, even tiny budgets for one-of-a-kind missions like New Horizons are fighting for their lives. Trump is asking Congress to cut the NASA science budget by half. NASA is pulling out of key collaborations with European space agencies even as a useless joint venture with Russia continues to consume $3 billion/year of our space budget. And plans are moving forward for a moon base that will be no more than a lunar junkyard, since we lack the ability to land a crew there.

We’re long overdue for a conversation about what the American space program is trying to achieve, and who, outside of the White House and Administrator’s office, it is supposed to serve.

Further Reading

• Text of a June 2026 memo from the Mars Exploration Program Analysis Group (MEPAG) setting forth their deep concerns with Skyfall.
• For those who want to nerd out on nuclear electric rockets, a detailed closeout report on Project Prometheus, an ambitious nuclear electric space probe to the outer planets that NASA cancelled in 2005.
• The Planetary Society’s Casey Dreier on the shortsightedness of Isaacman’s plan to convert Mars engineering testbeds into a lunar rover.

How big the reactor needs to be depends on the fuel. The reactor on SR-1 Freedom uses ~20% enriched uranium, which is less of a regulatory hassle. In designs that use highly-enriched uranium (90%+ U-235), the reactor could be as small as a roll of paper towels. The tradeoff is between smaller size and the hassles of navigating the nuclear bureaucracy on Earth.

It’s hard to tell what’s going on with the solar panels. The first render didn’t have them, while the later render does. But in that render, they also extend out of the cone-shaped shielded region behind the reactor, creating a secondary radiation hazard for the rest of the spacecraft and payload.

So far the House Appropriations Committee’s response to Isaacman repurposing Gateway funds has been “lol no”. In their 2027 bill, they allocate $10 million to SR-1 Freedom, which is just open trolling. Whether Isaacman can shuffle this much money around to create programs out of thin air is ultimately a question for the Government Accounting Office, the courts, and Congress.

Examples of past such boondoggles include Gravity Probe B, the Alpha Magnetic Spectrometer on the International Space Station, and the Deep Space Climate Observatory, affectionately known as GoreSat.

My guess would be $100-$150 million just for the helicopter design (compare $80M for Ingenuity), and then $300-$400 million to refine, test and validate a mechanism for flying the choppers out of their aeroshell. Note that Skyfall also has to sit for a year in a pretty spicy radiation field on the back of that nuclear reactor, which requires its own testing, design, and mitigation.