A gas gun launcher has a pump tube and a launch tube with a first end of the launch tube slidably inserted into a second end of the pump tube. The pump tube may hold a heat exchanger to heat a light gas used to launch a vehicle. A sliding seal can be employed to manage recoil and to retain the gas within the launch tube and the pump tube. A fast-closing muffler at the second end of the launch tube can conserve the light gas utilized for launching a vehicle, enabling the light gas to be recycled. A launch tube alignment system is preferably automatic, ensuring the survival of the launch vehicle.