To offset the danger of radiation in space, it is proposed that precast concrete panels be manufactured and assembled into modules on the Moon and launched into orbit from a precast concrete guideway system. Once in lunar orbit, the modules can be docked together and assembled into a spacecraft. The key to the concept is that, because the escape velocity of the Moon is only one-fourth that of the Earth and since the Moon has no air, a spacecraft can be launched from the Moon's surface much more efficiently than from the Earth.
