Disclosed is a high altitude space launcher system for transferring payloads from surface to orbit at a significantly lower cost than conventional rockets. It comprises a aerostat lifted one stage light gas gun operating in stratosphere that shoots rocket assisted projectiles containing payload at near orbital velocities to a low angle trajectory. Alternatively, to launch acceleration sensitive payloads such as astronauts the light gas gun is replaced with a muzzle loaded conventional gun that shoots a single stage rocket at a much lower velocity. The system is mostly static structure, attached to a tether-elevator that moors it to land or a ship and provided it with electricity and lifts the projectiles to the gun.