Allow me to preface the title: Longshot Space wants to build a 6-mile-long (10-km) space cannon to shoot several-ton objects into low Earth orbit (LEO). The company has already built a working proof of concept.
What can we do to RADICALLY drop the price of launch in the scope of 10 years? It doesn't have to be what I'm doing ... but somebody should do something.
I had an opportunity to sit down with the CEO and founder of Longshot, Mike Grace. "Longshot?" you ask? Prior to the other week, I'd have said the same. This was a company I'd not heard of in an area of which I'm not all that familiar with – flinging stuff into orbit sans rockets. SpinLaunch, sure.
You see, the other week I was forwarded an email from the boss that read something along the lines of "I'm super busy, but I think Joe would be up for it." Loz knows me pretty well over the last dozen or so years of collaborating on various projects. If he says I'd be interested, he's likely right.
Two years ago, Loz had written an article with "Nazi über-cannon" in the title. I balked when I read the title, but was immediately sucked into this wild idea and this equally wild CEO and how he was addressing potential investors.
Longshot wants to fire stuff out of a staged gas-powered cannon into space. And when I say cannon, I mean miles and miles of cannon at Mach 23. Wait, what?
We'll dig through history for a moment before getting back to present day:
The concept of using cannons to special-delivery items – iron balls, langrage, sabots, 155-mm HE shells, APFSDS long-rod darts – to neighboring villages and cities has been around for about 700 years ... you know, tools for war, death and destruction.
The concept of using cannons to blast people (or things) into space has been around since at least the 19th century, when Jules Verne penned the 1865 banger From the Earth to the Moon. In it, some bored artillery engineers build a massive 900-ft (274-m) cannon called the Columbiad. It's stuffed with a 9-ft (2.7-m) diameter capsule for three adventure-seeking astronauts and 20,000 lb of gun cotton to get the party started. I won't spoil the book for you if you haven't read it. I just wanted to illustrate that the idea has existed since long before you and I were born.
Fun fact: in the book, they launch from what's basically modern-day Cape Canaveral in Florida. And when they return to Earth? Yep, splash down in the ocean, just like the modern era. That Verne guy had it figured out. Never mind the 22,000 g's needed to get out of Earth's atmosphere.
Skip forward to the 1960s, when an upstanding Canadian gentleman by the name of Gerald Bull dials it up to 11 with Project HARP (High Altitude Research Project). The HARP team welded two 68-ft-long (20.7-m) 16-in/50 Mark 7 naval gun tubes with 16-inch (406.4-mm) bore diameters end-to-end as if they were straws and spitballs. With this 119-ft (36-m) monster cannon – about the same length as the infamous WWI Paris Gun – they shot something called the Marlet 2C 111.85 miles (180 km) into the air, well above the Kármán line – the transition between the atmosphere and outer space.
Done deal, right? Well, no, not exactly. Bull was able to send the Marlet 2C into space proper, but he shot it up, rather than across. It had the height, but not nearly the horizontal velocity to reach orbit and stay there. Bull's best shots – and there were over 200 – managed around Mach 6 ... but to reach space AND stay in orbit from a near-flat trajectory – like with Longshot's space potato gun – you'd need to reach something more like Mach 23.
There's a ton more to the Gerald Bull story ... like building weapons for Saddam Hussein and Mossad assassination stuff. There was even a 1994 Kevin Spacey movie about Bull called Doomsday Gun (it's not particularly good).
So, back to present day and Longshot
Mach 23 is pretty fast. It's the kind of fast where the air you and I breathe stops being just air. At that speed, air friction can heat a surface to nearly 3,000 degrees of nope (1,650 degrees of C nope) in about a second. In fact, it's not even air anymore – it's plasma. The very same stuff used to quickly cut through 10-inch-thick steel plates you'd find on an aircraft carrier.
How do you expect to launch something made of delicate electronics at insta-vaporize speed and still expect it to remain delicate electronics by the time you punch out of the atmosphere?
Mass. At least, according to Mike Grace, that's how Longshot is going to succeed.
If you want to send a 1,000 lb (454-kg) object into space at Mach 23, put 3,000 lb (1,360-kg) of packing material around it that you don't mind when it simply ablates into vapor as it shoots like a flaming reverse meteorite into the sky. If you want to shoot a 40,000-lb (18,144-kg) object into space, put 4,000 lb (1,814 kg) of packing material around it. The gun becomes more efficient as it's scaled up.
If that sounds crazy, you're not wrong. I never specifically asked Mike Grace why the company is called Longshot. I kind of wanted to just form my own opinions on the double entendre name and leave the real reason a mystery. Is it because the company has a low chance of succeeding? Or maybe because Grace wants to build a literal 6-mile-long (10-km) space gun, and the company would literally be making really long shots? Is he a Seth Rogen and Charlize Theron fan? Frankly, any of those answers seem plausible.
The idea is that as you scale up your payload, your surface-area-to-volume ratio gets better, meaning less payload gets burned off as sacrifice material and more survives the Mach 23 smelt.
The "vehicle," as Grace calls it, functions kind of like the world's biggest shotgun shell. In a shotgun, you've got propellant in the back, then wadding, then the payload (shot). Same basic idea here: the front of Longshot's vehicle – the part carrying the payload – is blunt, and the rear tapers into a flat, two-sided pressure-catching skirt. The whole design looks very much like a wedge you'd split wood with. The compressed gas tanks (air for now, hydrogen in the future) along the barrel are the propellant. Ahead of the vehicle, however, Longshot pulls a vacuum to reduce initial drag.
We're in the balloon popping business.
What makes Longshot's design particularly interesting is the skirt. It's not for flight – it's built to catch sideways high-pressure blasts. As the vehicle travels down the barrel, it passes a pair of high-pressure gas canisters (similar to scuba tanks at around 3,000 psi) mounted opposite each other, sealed by burst disks that are timed to pop at the exact moment the skirt slides through, firing into that tapered tail. The oblique shock creates instantaneous pressure, kicking the vehicle forward with significantly more force than just dumping more gas in the barrel behind it.
Rinse, repeat, as every pair of compressed gas canisters blows, another shock loads the skirt, stacking more and more speed on its way to Mach "now-we-have-to-solve-for-x."
It's called shock-impingement thrust, and it totally works. You've probably even created the same effect yourself – like missing that nail you were trying to hammer by just enough to send it sailing sideways into the ether, never to be found again. That sudden angled impulse is the same physics Longshot is banking on.
Go big or go home.
Grace has three different models in mind for his space gun: Baby Bear, Momma Bear, and Pappa Bear. The lattermost being his sort of pipe-dream, no pun intended, of building a 19-25-mile-long (30–40-km) gun that has a 30-ft (9.14-m) diameter barrel. It sounds ridiculous, honestly, until you start taking the little things into account, like physics.
Acceleration is force divided by mass.
Since Longshot is calling this a space gun, we'll use a regular Earth gun as an example. For a final given velocity, the shorter the barrel, like a handgun, the faster you have to apply the necessary force. That means higher instant acceleration and g-loads. Totally fine for a small piece of lead encased in a full metal jacket. However, as you make the barrel longer, you can reach the same final velocity with lower peak g-forces, as the bullet has more time and distance to gradually ramp up its speed. Every time you double the length of the barrel, you're reducing g's by half. Not only less g-load, but also less heat.
Getting a payload to Mach 23 speeds in 1,000 ft (305 m) is an explosive punch – and an expensive way of making glitter. Getting payload up to the same Mach 23 speed over 6 miles (9.7 km) is more like an increasing push over a long distance, comparatively. Grace believes his space gun could cut g-figures down to about 500. And for illustrative purposes, the phone probably in your hand right now is likely designed to withstand about 900 g's – thankfully, for all the butterfingers out there dropping their phones.
Pappa Bear, Grace's "if I can do whatever I want, where I want, how I want" space gun, well, he thinks it could get down to 100-150 g's on launch. Still far too many g's to launch anyone who isn't Chuck Norris into space, but well within the limits for anything not biological that would otherwise ride to space in a rocket.
So, you woke up one day and decided you were going to shoot stuff into space?
Grace's idea isn't uniquely his own. When I asked him what inspired Longshot, he told me about a Google TechTalk video he'd seen in 2009 of Dr John Hunter's Quicklaunch presentation titled Cannons to the Planets. Hunter had previously worked on the Super High Altitude Research Project (SHARP), which was similar to Bull's HARP project, but used light-gas rather than explosive propellants. In Cannons to the Planets, Hunter described submerging most of a 3,281-ft (1,000-m) hydrogen-powered launch tube at an angle, mounted to the bottom of an oil derrick floating at sea, so that it could be aimed to launch stuff into LEO ... which wasn't at all dissimilar from the Sea Launch Zenit program.
As with most ideas, one sparks another, and now it's Grace carrying the torch. My favorite thing I've heard Grace say is, "If you want to do something in aerospace engineering, your task is to find something a German dude worked on in the 1930s and steal it." Grace leans heavily on taking old, great ideas that can be polished rather than trying to invent new ones.
Launch remains the largest barrier, not only to LEO, but to deploying all the infrastructure that makes the rest of the solar system actually available to us.
Elon Musk has done a pretty good job as of late in getting goods into space. It costs around US$3,000 per kg using Falcon 9 rockets. Musk says Starship will cut that down to $500 per kg once it's all said and done. In space terms, that's "pretty cheap" and "whoa!" respectively. Grace reckons he can get payloads into space for as little as $10 per kilo using little more than concrete, steel and hydrogen. That's not even the same playing field anymore.
As of now, Longshot has had a working 6-inch-diameter (15-cm) mini version of its space gun in an ex-autobody shop in Oakland, California. It's been fired over 100 times so far and has reached speeds of Mach 4.2 – "4.5 if you squint," says Grace. But small scale means high g's – about 30,000 in this case.
Longshot has just built a bigger 30-inch (76-cm) gun that's 120 feet (36.6 m) long and has three units of pressure tanks, staged at the old Alameda Naval Shipyards in California. The company has yet to fire it, as it's waiting on use permits from the city of Alameda, but Longshot is very much ready to start test yeeting.
Grace told me that he thinks it might be the longest operational gun on the planet right now – though it has yet to operate. Just to be sure, I checked, and Longshot's Alameda gun is a mere 83.4 ft (11.14 m) longer than the Soviet 2S7M Malka, so yeah, Grace wasn't wrong about that.
The Alameda 30-incher is an analog for a 1,600-ft (488-m), 20-unit space gun Longshot is going to build at the airport in a tiny, high-desert Nevada town smack between Reno and Las Vegas called Tonopah. There are still a few FAA hurdles to cross, but the town of Tonopah has been very receptive to Longshot and what it wants to accomplish.
We can test it here in the Bay Area where all the eggheads live, and then we go out to Nevada to do the work.
Kinetic launch friends with benefits
While chatting with Grace, he told me about a company called Impulse Space. It's essentially a company that wants to build tugs in space for final-mile delivery.
"Toot-toot, Steamboat Willie! Go pick up a satellite, go drop it off somewhere else, and then refuel, and then do it again," explains Grace. "And so what you're telling your customer is you don't have to put a motor on your thing. You can just buy services from me and I'll deliver you there. And that makes your satellite better, because you can spend your budget of mass doing the thing you care about."
That means satellite companies could forgo expensive guidance systems while Impulse Space plays orbit-Uber. And that's just one of a whole lot of sci-fi scenarios that make space inherently cheaper.
As all of Longshot's infrastructure would be on the ground, reloading the space gun would be easy. Grace thinks the system could be capable of dozens of launches per day at a ridiculously low price per pound.
I wanna crack open the solar system like a [expletive] egg!
It sounds like an incredibly simple yet seemingly impossible solution. Longshot Space has already garnered investments from people like Sam Altman, CEO of OpenAI. Even the United States Air Force has chipped in grant money. If they're investing, there might be something to it ... but there's still a lot to overcome, or else Longshot simply won't work.
And if it doesn't, Grace told Relentless in an interview, "If I can't go to space, okay, I'll sell all the defense applications to Raytheon and cry my little eyes out from the cocaine island that I've built ... crying with my $100 bills to wipe my tears, lighting Fabergé eggs on fire every morning. I'll be super loaded and it'll be fine."
But then again, it just might.
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