Inspired by this xkcd, which calculated the energy requirements for accelerating individual humans to escape velocity (regardless of consideration for what that would do to your organs), I am interested to know if a trebuchet (or catapult) could be built that could launch things out off the Earth. Escape velocity isn't necessary, as I'd consider a stable orbit 'off earth'.
What would be some design considerations / challenges? Do we have materials that could withstand this type of force?
What would be maximum weight limits, ignoring air resistance (a tennis ball? a human? a satellite? a human in a metal survival pod?)
What would be the speed at which these objects would need to reach at the earth's surface to be into a stable orbital velocity by the time they exit the atmosphere? (factoring gravitational slowdown and air resistance)
Is it ever conceivable that we could 'launch' supplies to the ISS or orbit this way? What about launching satellites like this?
I misspoke when I said catapult, a string tension driven device. I meant a trebuchet, a gravity-powered heavy-object thrower. QuickLaunch, Inc. has plans to do just this launching a SSTO rocket at 6 km/s, which then fires after launch and provides the necessary correction for orbital insertion. Basically, I just need a trebuchet that will accelerate a mass (they're trying 1kg, 10kg, 50kg and 500kg masses) to 6 km/s at launch.