A bold ambition is taking shape: Longshot, an American company, is pursuing a 40-kilometer-long cannon that could hurl satellites into orbit—without rockets. Test shots and early designs are already underway, turning a science-fiction premise into a serious engineering project. Here’s how this proposal works and why it matters.
Why resort to a cannon for space access? Longshot argues that cost is the driving factor. Traditional rockets can cost about $3,000 per kilogram of payload, while a cannon-based system could potentially drop that figure to around $10 per kilogram. The notion sounds extraordinary, but it isn’t entirely new. Cannons have long propelled projectiles across battlefields; the challenge now is to push objects beyond the atmosphere instead of across a battlefield.
To make this feasible, the cannon must be colossal—more than 10 kilometers in length—and capable of firing at speeds around Mach 23. A longer barrel reduces the acceleration forces acting on the payload, which cuts heat and structural stress. In fact, doubling the barrel length halves the g-forces, easing the demands on the payload and its containment.
From Verne to real-world experiments
The concept echoes Jules Verne’s 1865 novel From the Earth to the Moon, where a giant cannon launched explorers toward the Moon. Verne’s plot overlooked a critical obstacle: human bodies cannot withstand such accelerations. In modern history, the idea resurfaced with the High Altitude Research Project (HARP) in the 1960s—a joint Canadian-American military effort. HARP welded naval gun barrels into a 40-meter tube and fired a 180-kilogram projectile, the Martlet 2, to an altitude of 180 kilometers, crossing the Kármán line that marks space’s boundary. Yet achieving orbit requires substantial horizontal velocity; the Martlet 2’s peak Mach 6 speed wasn’t enough. At Mach 23, air would become plasma, and the projectile’s surface could reach about 1,650°C (roughly 3,000°F).
How the launch would work at the edge of space
To survive such intense speeds, Longshot designs include a protective shell around the payload. For example, a 454-kilogram spacecraft might be encased in a 1,360-kilogram shell that burns off during ascent, shedding mass while preserving the orbital velocity needed for orbit.
The projectiles resemble futuristic bullets: a rounded nose to cradle the payload, with a flatter rear for stability. Instead of gunpowder, Longshot plans to use compressed air for propulsion, with hydrogen as a potential future energy source. To reduce drag, the barrel’s front would be evacuated to a vacuum before launch, while bursts of compressed air strike the projectile’s rear fins. This “impact thrust” would occur repeatedly along the barrel, stacking velocity with each burst.
So far, the team has built an 18-meter, working prototype equipped with three secondary boosters. It can launch a 15-centimeter projectile at roughly Mach 4.2, and more than 100 tests have been conducted to date.
Big leap ahead or a perpetual long shot?
The next milestones are scaling up to a 36.6-meter version, followed by the final aim of a 40-kilometer cannon with a 9-meter barrel diameter. It is an audacious objective that challenges conventional space-launch thinking, and Longshot’s CEO insists it is achievable.
Even if the system doesn’t become a practical space launcher, the military implications are clear. Cheaper access to space could reshape defense, telecommunications, and earth observation capabilities, while still opening the door to debates about risk, practicality, and ethics.
Bottom line: Longshot’s bold pursuit shows that the most radical ideas often begin with a single, decisive blast—and that pushing beyond the familiar boundary between science fiction and engineering can spark real conversations about the future of space access.
Sylvain Biget
Journalist
Sylvain Biget is a journalist who focuses on technology and its societal impact. A graduate of the École Supérieure de Journalisme de Paris, he has built a career reporting for high-tech outlets. He also holds a private pilot license and is a certified professional drone operator, blending aviation interest with tech analysis.
As a member of Futura’s editorial team, he covers cybersecurity, electric mobility, drones, space science, and emerging technologies. He aims to keep readers informed about today’s tech advances and to explore how tomorrow’s innovations might reshape our world. His interest in artificial intelligence informs a nuanced perspective on the challenges and opportunities of the tech revolution.
