The era of reusable space transportation began with the Space Transportation System, or Space Shuttle, in 1981. In reality, the Space Shuttle consisted of a refurbishable Orbiter and Solid Rocket Boosters mounted to an expendable External Tank. Considerable effort was required to inspect, test, and prepare the Orbiter and Solid Rocket Boosters for their next flight. Today, SpaceX is recovering and reflying their Falcon 9 rocket first stage with some between-flight maintenance and Blue Origin flew its suborbital New Shepard five times with minimal maintenance between flights. New systems, such as Stratolaunch and DARPA’s XS-1, are also focused on reusable first stages. But this only addresses the Earth to orbit mission leg.
Eventually, all Space transportation systems will be reusable. Cislunar Space Development Company, LLC is focused on developing two types of reusable in-Space transportation vehicles: orbit transfer vehicles and lunar landers. Orbit transfer vehicles will operate between Low Earth Orbit and Earth-Moon Lagrange Point 1 while the lunar lander will fly between Earth-Moon Lagrange Point 1 and the Moon’s surface.
Reusable in-Space transportation systems need a place to refill their propellant tanks and pick up their next payload. Initially, the orbit transfer vehicle will meet with a propellant tanker from Earth to refill its tanks and then pick up its mission payload. Eventually, a Low Earth Orbit Transportation Node is assembled as the first infrastructure system. A second Transportation Node will be established at Earth-Moon Lagrange Point 1 and a third on the Moon’s surface. Transportation Nodes provide a docking port and some housekeeping services to the transportation vehicles between missions in addition to producing liquid oxygen and liquid hydrogen propellants from water. Water may be delivered from Earth, the Moon or near Earth asteroids. Housekeeping services include power, communications, orbit maintenance and micrometeoroid and orbital debris protection. Similar housekeeping services are provided to payloads between delivery from Earth and transport to their operational destination.