DescriptionOrbital propellant depot - Space transportation system 1971.jpg
English: In this artist's concept from 1971, an Earth-to orbit fuel tanker approaches the Orbital Propellant Depot. As envisioned by Marshall Space Flight Center Program Development planners, an orbital modular propellant storage depot, supplied periodically by the Space Shuttle or Earth-to-orbit fuel tankers would be critical in making available large amounts of fuel to various orbital vehicles and spacecraft.
The NASA website hosts a large number of images from the Soviet/Russian space agency, and other non-American space agencies. These are not necessarily in the public domain.
The SOHO (ESA & NASA) joint project implies that all materials created by its probe are copyrighted and require permission for commercial non-educational use. [2]