English: Full Description: In this 1989 artist's concept, the Shuttle-C floats in space with its cargo bay doors open. As envisioned by Marshall Space Flight Center planners, the Shuttle-C would be an unmanned heavy lift cargo vehicle derived from Space Shuttle elements. The vehicle would utilize the basic Shuttle propulsion units (Solid Rocket Boosters, Space Shuttle Main Engine, External Tank), but would replace the Orbiter with an unmanned Shuttle-C Cargo Element (SCE). The SCE would have a payload bay length of eighty-two feet, compared to sixty feet for the Orbiter cargo bay, and would be able to deliver 170,000 pound payloads to low Earth orbit, more than three times the Orbiter's capacity.