Concept art has a multitude of uses outside of the film and gaming industries, even out in the “real world” — theme parks for example, use concept art to plan attractions.
Another use is in the development of proposed space vehicles, this has been the case since Chesley Bonestell created images of potential spacecraft for an American space program that did not yet exist, working from sketches on graph paper by pioneering rocket scientist Wernher von Braun. (The concept paintings were initially used to convince Congress to fund the space program by showing them the possibilities.)
An article today by Robert Gonzalez on the excellent science fiction/science themed blog, io9, digs into the archives of the San Diego Air & Space Museum and comes up with a treasure trove of concept art from the proposal days of the U.S. Space Shuttle program in a Flickr set of Space Related Images from the museum.
The concept art, which shows many preliminary and alternate designs, is mixed in with photographs of actual launches, tests and related subjects, but there is enough art to make flipping through the thumbnails well worthwhile. The io9 article also showcases some highlights with links to large versions. These images are in the public domain.
You’ve probably seen images recently of the last Space Shuttle’s last flight atop a carrier plane as it was moved to its resting place in a museum. The image above, top, was a concept for how the spacecraft might be carried atop existing aircraft for transport that was created before the Shuttles existed. Concept to reality.