"We're Building the World's Biggest Gun to Shoot Refrigerators at Mach 20": Mike Grace, CEO of Longshot, Is Building the Space Cannon That Could Make Rockets Obsolete

In 1944, Allied bombers were turning Germany into rubble. Resources were scarce. The Third Reich was collapsing. And yet, German engineers were building a 130-meter cannon with 28 side chambers designed to shell London from 165 kilometers away. The V-3 "supergun" never fulfilled Hitler's revenge fantasies, but it did prove something Silicon Valley is only now rediscovering: you don't need rockets to reach space. You just need a really, really big gun.

Mike Grace knows this because he's building one. Not in some classified military facility, but in a former auto shop in Oakland, wedged between an asbestos testing lab and a storage unit full of Capri-Suns. His company, Longshot Space, has attracted millions from Sam Altman and Tim Draper by promising something that sounds absurd: firing satellites into orbit using compressed gas, like the world's most expensive potato gun. Traditional cannons would turn those satellites into expensive confetti with 50,000 Gs of acceleration. Grace's sequential-chamber design drops that to a manageable 500 Gs. The economics are so brutal, so obvious, that Grace can barely contain his frustration when explaining them to investors who keep asking why nobody's done this before.

"The technology has been sitting on the shelf for decades," Grace tells me, speaking quickly as if he's running out of time to save the space industry from itself. "It worked in the 1940s while the Germans were getting bombed to shit. The market just wasn't ready." That market readiness came courtesy of Elon Musk, who proved cheaper launch costs equal money printing. But while SpaceX keeps building bigger rockets—magnificent rockets, game-changing rockets—Grace sees them as beautiful dead ends. Rockets are islands. Everything that makes them work has to fly: fuel, engines, tanks, all of it. His gun keeps the expensive bits on the ground.

The numbers are stark. SpaceX charges $3,000 per kilogram to orbit. Grace is targeting $10. At that price, space colonies stop being PowerPoints and start being subdivisions.

You went from combat engineer handling explosives to building a space gun in Oakland. Walk me through the physics—what makes kinetic launch viable now that wasn't possible when Gerald Bull tried with Project HARP? What's the secret sauce?

"The physics are dead simple," Grace begins, with the tone of someone who's explained this too many times to venture capitalists who still don't get it. "Here's what's counterintuitive—what makes this viable today isn't new technology. The technology has been sitting on the shelf for 80 years. What's changed is the market."

He pivots to a quick history lesson: "The Germans built a supergun in World War Two called the V-3 that's actually a much better analog for what we're building than HARP, though HARP is a wonderful story to tell. But the V-3 worked—it worked in the 1940s while the Germans were getting bombed to shit by the Americans and the British."

The V-3 wasn't just big. It was brilliant. "It's a multi-chamber gun, which means instead of one massive boom, it goes bump-bump-bump-bump. Every time you double the number of injection chambers, you cut the maximum pressure in half, cut the maximum temperature in half, and cut the acceleration forces on your payload in half." This matters because satellites are fragile. Traditional cannons generate 40,000-50,000 Gs of acceleration, enough to turn electronics into powder. The V-3's sequential injection design drops that dramatically.

If the engineering was sound, why didn’t it change the world back then? Grace draws the line from physics to geopolitics. "After World War II, everyone wanted advanced aerospace systems as strategic weapons. Here's the problem…you can hide a rocket. You'll never hide a supergun."

The Cold War only reinforced that logic. "Mutually assured destruction was three-card Monte: you're hiding your assets from the Russians, they're hiding theirs from you. Nobody cared about marginal cost. If one out of 50 of your thermonuclear ICBMs fails on launch, who cares? You still wiped 49 enemy cities off the map.” Grace continues, “Kinetic launch's core advantage is low marginal cost. But if you're starting World War III, marginal cost is completely irrelevant."

Today, the calculus is different. Everything changed with SpaceX: "What's absolutely clear today is that lower launch costs equal money printing. That's unambiguous. The physics advantage, he adds, almost feels obvious. "Rockets are hard because they're islands: no extension cord out the back. Everything that does the work has to fly with the payload. It's completely self-contained. With kinetic launch, all the energy and infrastructure stays on the ground. I can solve engineering problems with massive amounts of steel and concrete. That's it."

Your system promises radical cost reduction for payloads. Let's talk limits first—what g-forces are we talking about? What survives being shot from a gun, and what definitely doesn't? Give us the engineering reality.

"Everything about our system gets better with scale," Grace states, like a professor who's about to blow your mind with counterintuitive physics. "Build the gun bigger, everything improves. The gun itself becomes more efficient."

He explains how the physics reward size in surprising ways. "As the tube diameter increases, the pusher plate behind the vehicle gets longer, which means each injection event can impart more energy."

Length adds another advantage. “Double the gun length, cut the maximum acceleration in half. A 10-kilometer gun gives you around 400–500 Gs maximum.”

For perspective, that's harsh but manageable. Artillery shells endure 40,000-50,000 Gs. Fighter pilots black out around 9 Gs. "Your phone can survive about 900 Gs. Surface-mounted electronics are surprisingly robust."

His target payload sounds mundane until you consider what it implies. “Satellites like Starlink—refrigerator-sized, maybe two refrigerators. I want those to survive naturally. They’re already designed to be robust because rockets shake the hell out of them during launch. At 500 Gs, anything that survives vibration testing should survive our launch.”

And that’s just the baseline. “Ten kilometers is the minimum viable product,” he continues. “I’d rather build something 30 or 40 kilometers long. Then you’re down to 100–150 Gs.”

The atmosphere, he points out, brings its own physics lesson. “Throw a feather at Mach 5, it stops immediately and bursts into flames. Throw a bowling ball at Mach 5, it goes through several houses before stopping.”

That’s where mass becomes an ally. “Minimum viable is probably a two-ton projectile with just under one ton of useful payload. The rest is ablative shielding and structure.”

Scale keeps shifting the equation. “A 20-ton vehicle gives you 17–18 tons of payload,” Grace says. “This approach demands you go big.”

From a defense perspective, kinetic launch changes the game for responsive space access. If conflict takes out traditional launch sites, how quickly could Longshot deploy replacement satellites? What's the real setup time from truck to trajectory?

“I want to launch multiple times per day,” Grace says matter-of-factly, as if he’s talking bus schedules rather than rewriting the rules of space access. “That would’ve been insane to say ten years ago. Today it’s completely achievable.”

He points first to a strategic shift toward ultra-low orbits. “SpaceX is now talking about deploying Starlink and Starshield constellations at 150–250 kilometers altitude. That gets you fiber-competitive latency.”

Those orbits, he explains, fundamentally change the nature of space warfare. “The Kessler effect doesn’t really matter anymore. If one of those satellites is destroyed, the components have a much worse ballistic coefficient than the whole satellite, so they decelerate and burn up very quickly.”

The implication is clear: adversaries can no longer deny access by creating long-lived debris fields. “At 125 kilometers altitude, debris won’t last,” Grace says. “You can’t shut down space with chaff.”

Instead, he envisions truly disposable constellations. “Satellites designed to last for a day. They orbit Earth about forty times, then decay and burn up. And then you just launch more of them.”

Economics become the decisive weapon. “During conflict you deploy an ablative constellation—cheap sensors that give you eyes in the sky for discrete periods, so inexpensive it’s Sisyphean for an enemy to shoot at them. They can fire multi-million-dollar rockets at our CubeSat sensors, but we’ll just launch more. Multiple times a day, in clouds. What are they going to do?”

Grace acknowledges a trade-off. “It’s fixed infrastructure of a scale that I’m skeptical you’d be able to hide.” Yet speed shifts the balance back in his favor. “The THAAD (Terminal High Altitude Area Defense) missile system intercepts ballistic missiles during their terminal phase, the last stage of flight as they descend toward the target. It accelerates to Mach 15 over three minutes, but that three-minute boost phase is its vulnerability window. A kinetic launch system can take a comparable payload to speed in one second. There’s no boost phase to target—we’re at top speed the instant you hit the button.”

Your background spans molecular biology at NASA to explosives safety. That's an unusual mix. How does understanding directed evolution inform building better launch systems? What biological principles apply to shooting things into space?

“Directed evolution in molecular biology, bacterial genetics—that’s really my thing,” Grace explains. “Think about it as animal husbandry for very, very small animals. I was breeding bacteria to get them to do what I wanted rather than tinkering with individual genes.”

His master’s research sounds almost like science fiction. “I was engineering them to tolerate higher concentrations of electronics waste. I was literally putting cell phones into a blender, turning them into slurry, and growing organisms on higher concentrations of the stuff.”

For Grace, the link between biology and engineering is clear. “I don’t want to interact with complex systems from first principles if I can avoid it. The way to interact with really complex systems is this black-box approach.”

He points to history to show how effective that mindset can be. “Most modern crops, like the banana, were bred from almost inedible berries by people who thought the sun could get mad at them. They accomplished incredible genetic engineering because they understood basic principles about heritability.”

Grace’s own bacterial work proved the concept. “I engineered E. coli to be more radiation-resistant than Deinococcus radiodurans (nicknamed ‘Conan the Bacterium’), which can survive 5,000 times more radiation than would kill a human. It literally grows on the walls inside nuclear reactors, repairing its own DNA faster than radiation can destroy it. By blasting E. coli with UV-C light cyclically, killing 99% and letting the survivors regrow, I created in a week a radiation-resistant organism far better than nature’s best.”

That philosophy now shapes Longshot. “You must be humble about your ability to understand complex systems from first principles. Taking a systems view (stepping back) can be really powerful. Let go of first-principles knowledge for the moment and try to get the outcome you want.”

Let's talk vulnerabilities. Traditional rockets are sitting ducks. But a kinetic launcher could theoretically be hidden anywhere. What new security challenges does this create? How do we prevent adversaries from building clandestine space guns?

“I’m skeptical,” Grace responds immediately, with the confidence of someone who has war-gamed every scenario. “Kinetic launch systems are actually really easy to spot because they’re large-scale industrial projects.”

He draws a direct comparison to existing strategic infrastructure. “They occupy a similar role as nuclear silos. America knows where every Chinese missile silo is, and the Chinese know where every American missile silo is. These are pieces of large-scale fixed infrastructure.”

That makes detection virtually guaranteed. “If you’re seeing something moving in the lower atmosphere at Mach 20 and blazing hot, there aren’t many things it could be. Either a meteor is hitting, or you’re witnessing kinetic launch.”

Yet the systems bring a different set of advantages. “ICBMs start slow. The Saturn V takes off at walking pace and accelerates to orbital velocity over eight minutes. A kinetic launch system might take a comparable payload to speed in one second.”

That speed eliminates the usual window for interception. “If you’re trying to intercept an ICBM, you want to hit it before it gets to speed. Once it reaches Mach 15 to 25, the chances of hitting it are very low. With kinetic launch, it’s at top speed the second you hit the button.”

Grace sees these platforms becoming part of future force structures. “I wouldn’t be shocked if in 20–30 years you see these deployed by superpowers as part of a mix—bombers, ICBMs, submarines, and kinetic launch systems.”

And the concept isn’t entirely theoretical. “The Chinese are already thinking beyond rockets,” he adds. “They did a fractional orbital bombardment demonstration last year—circled Earth with a hypersonic glide system, then struck a fake carrier in the Gobi Desert. If you can put something into space, you can put it down anywhere on the planet.”

You've mentioned nearly going bankrupt multiple times, living off $30,000 for a year during COVID. You ranked ten startup ideas and deliberately chose the hardest one. Why do this to yourself? What drives someone with an economics degree to build space cannons instead of, say, a profitable SaaS company?

“I ranked them all in terms of how difficult they would be, one to ten, and how much they excited me. And Longshot was a ten and a ten,” Grace explains, with the satisfaction of someone who chose pain on purpose. “I knew it was going to be hard. But it called to me. I knew that it mattered.”

Far from a handicap, his economics background shapes that decision. “Elon Musk also has a bachelor’s degree in economics. That’s something he and I have in common. I think that helps. Engineers, when you’re a hammer, everything looks like a nail. They look at a world covered in rockets and think rockets must be the correct engineering solution. That’s incorrect.”

It’s a perspective that cuts through Silicon Valley orthodoxy. “There’s a bias toward technical novelty for this exact reason—not because the solution actually demands it, but because engineers think the way to solve problems is with new engineering solutions. Betamax was awesome. It was better than VHS. It just happened to be the case that VHS came out on top for reasons that had nothing to do with it.”

The near-death experiences started almost immediately. “I had the incredible timing to basically try and incorporate Longshot just as we were starting to hear about this weird flu thing happening in China. I was trying to raise pre-seed—friends and family money—at a time when nobody was investing. The world was ending.” Somehow he scraped by. “I managed to find somebody who put in $30,000, and we lived off that $30,000. We did work and lived off that for a year.”

Grace had already studied how startups fail and knew what to avoid. “I’ve lived in nothing but co-ops since I’ve been in the Bay Area, like hacker houses. I’d seen a lot of people whose startups had failed for lots of reasons, but if you scratch the surface, the real reason is the co-founders basically lose the will to do it. It’s super painful. It demands sacrifices for years.”

That observation shaped his resolve. “I just decided that with Longshot being so challenging, caring about it is actually the most important criterion. The numerous times we’ve nearly gone bankrupt—I could tell you stories—but we’ve made it so far, and I have absolutely no intention to stop.”

His economic lens also highlights opportunities engineers often miss. “In Silicon Valley, revisiting technologies of history that are already proven but didn’t have product-market fit is actually a much more viable approach than inventing something new. Lots of technologies get abandoned in history not for engineering reasons, but for product-market fit reasons.”

Grace even applies that thinking to energy policy. “The fossil fuel industry thinks nuclear power would be very competitive with their business model over time. They’ve spent money influencing anti-nuclear efforts while taking billions in subsidies themselves. But they’re important allies who’ve kept America in electricity and industrial dominance for a century. They should be praised for that, then encouraged to transition over two generations.”

The same logic extends to space. “You need economic thinking to see that container ships make airplanes more profitable, not less. There are a lot more airplanes flying around the planet today because there are container ships on the oceans. Those container ships facilitate global trade, make the entire world more wealthy, and increase the world’s capacity to buy airplane tickets.”

He sees an analogous future for spaceflight. “I think there are going to be a lot more rockets flying to space because kinetic launch exists, and there will be a lot more demand for material to be thrown to space because there are really cheap, successful rockets. These are two very different modalities of accessing space.”

Looking forward, where does kinetic launch fit in the broader space ecosystem? Are we talking niche applications for hardened payloads, or could this technology scale to challenge chemical rockets? Paint me the picture of space access in 2035.

“If I can get G-forces below 200 or 300, there’s basically nothing a rocket could launch that I can’t launch—except you and me,” Grace says with the certainty of someone who has run the numbers a thousand times. “You and I are going to continue to go to space on rockets for a long time.”$$

The real bottleneck, he argues, isn’t moving people but moving cargo. “It takes ten tons per person per year imported to Hawaii to maintain living standards, and that’s a tropical paradise. For space, you might need a hundred tons per person per year.”

At current prices, that math is impossible. “At $3,000 per kilogram on Falcon 9? Forget it. Trillions of dollars to sustain a small town. Even at $500 per kilogram where Starship might go—still forget it.”

Grace fixes on a single transformative figure. “If we get below ten dollars per kilogram, it’s not just governments anymore. Groups of people could afford colonies. Millions to tens of millions of dollars to support an asteroid colony.”

He stresses that kinetic launch complements rockets rather than replacing them. “I joke about competing with SpaceX, but I really want them to succeed because I want to go to space. I’m not stopping until there’s a corner office on the moon.”

To make the point, he reaches for a familiar comparison. “There are more airplanes flying today because container ships exist. Container ships facilitate global trade, make the world wealthier, increase capacity to buy plane tickets. These are different modalities—more rockets will fly because kinetic launch exists.” The first market, he notes, is obvious. “Telecommunications. Deploy satellites cheaper, print money.”

But once capacity scales, the possibilities turn almost science-fictional: "Companies want orbital mirrors to beam sunlight onto solar farms at night. Thousands of tons of reflector. Marginal at $1,000 per kilogram, instantly profitable below $100."

One early entrant, Reflect Orbital, already plans to deploy massive mylar mirrors in orbit to redirect sunlight onto solar farms after dark, effectively extending their operating hours. The company envisions satellites unfolding reflective surfaces the size of football fields to beam concentrated sunlight to specific locations on Earth, potentially doubling solar farm productivity.

Grace sees that as just the beginning. “Solve launch first in terms of capacity and cost. Then in-space fuel, logistics, power, communications. Build infrastructure in space that makes everything cheaper.” He finishes with a grin. “The 2030s and 2040s could have a lot of fucking science fiction. Stuff that sounds crazy today becomes inevitable.”

Author's Analysis

Mike Grace has spent four years telling Silicon Valley that German engineers solved cheap space access while being carpet-bombed, only to watch VCs fund another app that delivers groceries in 12 minutes instead of 15. The frustration radiates through every rapid-fire explanation, every historical reference, every barely contained "how do you not see this?" The most maddening part is he's right: rockets are inherently inefficient because they have to carry their own infrastructure. It's like requiring every car to pave its own road. Grace's gun keeps the infrastructure on the ground where God intended, using sequential gas injection to accelerate payloads without turning them into plasma. The Germans proved it worked. We abandoned it because you can't hide a 10-kilometer gun for nuclear deterrence. Now that SpaceX has made space profitable rather than strategic, the economics have flipped. And Grace—this former NASA lab tech who taught bacteria to eat cell phones—is the only one who noticed.

The defense implications feel like science fiction but aren't. One second to Mach 20. No warning. No boost phase to target. Just instantaneous deployment of surveillance satellites that cost less than the missiles needed to shoot them down. Grace talks about launching "clouds" of disposable satellites multiple times daily during conflicts, turning space denial into economic suicide for adversaries. When your enemy can replace destroyed satellites faster and cheaper than you can destroy them, you've lost before you've started. Meanwhile, China's testing fractional orbital bombardment while we're still arguing about rocket reusability. The 20-ton projectiles Grace envisions could carry entire satellite constellations in a single shot, deployed at prices that make current launch costs look like luxury taxes. Yet here he sits in Oakland, next to an asbestos lab, trying to convince people that sometimes the old solutions are the best solutions. That's the tragedy and comedy of Longshot Space: they're trying to revolutionize space access using Nazi artillery while Elon builds ever-bigger rockets. Both might be right. Or Grace might be the only one who is.

About Mike Grace

Mike Grace serves as CEO and co-founder of Longshot Space Technologies Corporation, developing kinetic launch systems for low-cost space access. After studying economics at North Carolina State University, Grace took an internship at NASA Ames Research Center, where a summer position evolved into nearly five years of research. He earned a master's degree in genetics from San Jose State University, specializing in directed evolution—engineering bacteria to consume electronics waste.

Following his academic work, Grace served in the U.S. Army as a combat engineer. In 2020, he co-founded Longshot Space with CTO Nathan Saichek in Oakland, California. The company has raised a total of $8 million from investors including OpenAI CEO Sam Altman, venture capitalist Tim Draper, and the U.S. Air Force's Tactical Funding Increase program. Their current 60-foot prototype in Oakland can accelerate projectiles to Mach 4.2, with plans for a 1,600-foot system in Nevada capable of hypersonic testing.

Grace enjoys board games and wearing inflatable T-rex costumes to events where they are not really appropriate. After ranking his startup ideas on difficulty and excitement, he chose the only one scoring 10/10 on both scales: Longshot Space. 

For more information, get in touch with Mike directly at grace@longshotspace.com.