The Problem with Rockets
Rockets are feats of engineering, but they are fundamentally inefficient. Much of a rocket's mass is fuel needed to lift not just the payload, but also itself and all the other fuel on board. This is dictated by what's known as the tyranny of the rocket equation.
Even with reusable rockets like SpaceX's Falcon 9, the process is costly, requires hazardous propellants, and has a slow turnaround time. Longshot Space, an Oakland, California-based startup founded in 2020 by CEO Mike Grace and CTO Nathan Saichek, argues that for sending inert cargo to space, there has to be a simpler, cheaper way. Their solution: keep the launch system on the ground.
Introducing the 'Space Gun'
Longshot's concept is a ground-based kinetic launch system—essentially, a giant pneumatic cannon. The idea itself isn't new, with historical precedents like Project HARP in the 1960s, which used a large gun to fire projectiles to the edge of space. However, Longshot is reviving and modernizing the concept with advanced technology. The system uses a very long barrel to accelerate a payload to hypersonic speeds using compressed gas. By leaving the heavy engines and fuel on Earth, the projectile can be much lighter and the cost per launch can be slashed dramatically. CEO Mike Grace estimates their system could eventually bring the cost of launching a kilogram to orbit down to just $10, compared to the thousands of dollars it costs with current rockets.
How It Works
Imagine a massive potato gun, but far more sophisticated. A payload is placed inside a long tube or barrel. Instead of a single explosive push, Longshot's system uses a technique called “multi-injection.” As the projectile speeds down the barrel, precisely timed injections of compressed gas are fired from ports along the sides. These jets of gas push against a long, tapered tail on the projectile, continuously adding velocity. This series of smaller, gentler pushes allows the payload to reach incredible speeds without being instantly crushed. The company has already built prototypes that have achieved speeds over Mach 4. The ultimate goal is to reach Mach 25, the speed required for low Earth orbit.
The Challenge of G-Forces
A major hurdle for any kinetic launch system is surviving the immense acceleration, or G-forces. Abrupt acceleration can destroy a payload. Longshot's solution is length. By accelerating the projectile over a very long distance—the final orbital version could be 10 to 15 kilometers long—the G-forces are distributed over time, making the ride much smoother. While competitors' concepts might subject payloads to 15,000 Gs or more, Longshot is targeting a more manageable 250 to 500 Gs. This is still far too intense for humans but is believed to be within the tolerance of many modern, ruggedized satellites, which are already built to withstand the intense vibrations of a rocket launch.
A Stepping Stone to Orbit
Reaching full orbital velocity from the ground is a monumental task. To bridge the gap, Longshot has a multi-stage business plan. The company's immediate market is hypersonic testing for military and commercial clients. Their system can provide a cost-effective way to test materials and vehicle designs at speeds above Mach 5, a service that currently requires expensive rocket launches. This strategy provides a path to revenue and technical validation. It has already attracted significant investment, including from OpenAI CEO Sam Altman and the U.S. Air Force. The plan is to build progressively larger accelerators, first at a site in Nevada, before attempting the full-scale orbital system, which may be located in a remote area like northern Australia to manage sonic booms.
