The Next SpaceX is a Giant Space Cannon

By South Park Commons

Categories: Startup, VC

Summary

Longshot Space is building a 15km space gun that accelerates projectiles to 8.5 km/s using staged hydrogen pressure vessels—a physics-based approach to space launch that requires solving the atmospheric drag problem after the initial 2.5 km/s acceleration phase.

Key Takeaways

  1. Traditional gas acceleration hits a hard physics ceiling at 2.5 km/s due to speed-of-sound limitations in hydrogen (1,270 m/s), where pressure behind projectile drops to <10% of initial PSI, making additional acceleration methods mandatory.
  2. Conviction for moonshot ideas requires demonstrating feasibility through math first—the SR-71 Blackbird was built by a small diverse engineering team with hard work and physics, not just massive budgets, establishing a historical precedent.
  3. Space launch via ballistic cannon requires 8.5 km/s muzzle velocity to achieve 7.5 km/s orbital speed after 1 km/s atmospheric loss—a specific technical target that guides all engineering decisions downstream.
  4. Multi-stage pressure injection via distributed burst discs along the barrel extends acceleration beyond single-chamber limitations—a novel engineering solution borrowed from potato cannon physics scaled to industrial proportions.
  5. Current proof-of-concept includes operational systems: a 6-inch diameter 60-ft cannon and a 30-inch diameter 120-ft cannon (world's largest), demonstrating rapid hardware iteration to validate concept before full-scale deployment.

Related topics

Transcript Excerpt

We're going to make a giant 15-km long space gun and we're going to shoot stuff into space. To most people that just sounds like, "No, you're not." >> [laughter] >> That's insane, right? >> Look, well, I did the math. Like, I've got the physics. The team that designed the SR-71 wasn't an army and it wasn't billions of dollars. They had a broad enough group of engineers with diverse talents and willingness to work really hard and, you know, magic happened. First thing you need for conviction is the idea that it might not be impossible. >> My name is John at the Wall of the South by Our Commons. I am privileged to be joined today by NATO Sidecheck, who is the co-founder and CTO of a company called Longshot Space. Uh where they are building a space gun? >> A space gun. >> Is that the preferre…

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