California Startup Bets on Giant Ground Gun to Slash Space Launch Costs

Longshot Space Technology, an Alameda, California startup, is developing a horizontal gun powerful enough to fire cargo toward space, aiming to collapse the work of a rocket's first stage into a reusable ground-based accelerator. The company has raised roughly $20 million from venture investors and is pitching kinetic launch as a path to dramatically cheaper mass to orbit.

Co-founders Mike Grace, the CEO, and Nato Saichek, the CTO, see an opportunity to repurpose a technology that has already proven its worth. Grace draws a comparison to SpaceX, which he says took "classically de-risked technology and scaled it aggressively." Where SpaceX built on NASA rocket research, Grace says Longshot will build on multi-injection guns, designs that give a projectile extra boosts as it travels down the barrel, originally developed for World War II and in 1960s research programs.

The system works like a steel pipe mounted horizontally, with tanks of high-pressure gas attached at ports along its length. As a projectile moves down the barrel, the tanks fire at precise times to accelerate it. The company is currently firing a 70-foot gun with a six-inch diameter at a test site near Barstow, California, reaching near-hypersonic speeds. It expects to begin firing a 140-foot gun with a 30-inch diameter at its Alameda site, then build a 30-inch diameter gun 328 feet long, with plans to extend it to about 3,000 feet. That version would be the largest gun on the planet, capable of launching 220-pound payloads to speeds of Mach 8.

Longshot's projectile is a lifting body, meaning its shape generates lift, so it gains altitude aerodynamically after leaving the barrel and the gun does not need to point upward. The guns also generate revenue through hypersonic testing for the U.S. military, which has awarded the company several contracts. Grace envisions placing a gun on a military installation such as Fort Bliss to help test next-generation interceptors. "If you want to practice shooting down a Chinese or Russian hypersonic missile, wouldn't it be nice not to pay $30 million for that?" Grace asks, describing a system that could provide "hypersonic clay pigeons" for a quarter or half a million dollars.

The team is confident it can scale the design to accelerate payloads to as much as five kilometers per second, more than 11,000 mph, fast enough to reach space if the payload carries its own propulsion system as a second stage. That would require a gun about six miles long and nearly 10 feet in diameter. Grace expects that, if the approach works, Longshot could send payloads to space for about $50 per kilogram. He notes that the orbital data center industry needs prices near $300 per kilogram to become viable, leaving room to offer a competitive price. Launching spacecraft in this form factor and under these conditions would require modification, but Grace argues satellite operators will be willing to try at that price point.

The main obstacle, Saichek jokes, is not engineering but real estate. "The hard part is not building the thing, it's finding a place where they will let you build the thing."

Longshot will present its approach this week at TechCrunch Disrupt in San Francisco, held Tuesday through Thursday. Next technical milestones include beginning tests of the 140-foot gun at Alameda and building out the larger 328-foot gun that the company plans eventually to extend to roughly 3,000 feet.