Physicist John Hunter has proposed the construction of a 1.1-kilometer-long cannon that could fire a 450 kg payload into orbit. David Shiga writes in New Scientist:

The gun is based on a smaller device Hunter helped to build in the 1990s while at the Lawrence Livermore National Laboratory (LLNL) in California. With a barrel 47 metres long, it used compressed hydrogen gas to fire projectiles weighing a few kilograms at speeds of up to 3 kilometres per second.

Now Hunter and two other ex-LLNL scientists have set up a company called Quicklaunch, based in San Diego, California, to create a more powerful version of the gun.

At the Space Investment Summit in Boston last week, Hunter described a design for a 1.1-kilometre-long gun that he says could launch 450-kilogram payloads at 6 kilometres per second. A small rocket engine would then boost the projectile into low-Earth orbit.

Pictured is a HARP gun, a Cold War-era device used to fire instruments into the upper atmosphere.

Link via Popular Science | Image: NASA