NASA's space shuttles are usually busy doing something cool for photographers. (Even in retirement, they know how to put on a show.) This picture, though, is cool in a very weird way: Space Shuttle Explorer crossing the Gulf of Mexico. Never heard of Explorer? We forgive you — it's a secret shuttle.
Explorer never went into space. Unlike Enterprise and Pathfinder, two other shuttles that aren't space worthy, Explorer didn't act as a simulator or aerial test bed, either.
Instead, it's a full-sized, faithful replica built using schematics of the space shuttles and installed at the Kennedy Space Center Visitor Complex in Florida in 1993. Now that KSC will be home to Space Shuttle Atlantis, Explorer is being transferred to the Johnson Space Center in Houston, Texas, where it will arrive later today.
While enroute across the Gulf of Mexico, Astronaut Greg "Astro Box" Johnson managed to snap the shots above and below, tweeting: "[Astronaut] Steve Robinson and I were flying the T-38 and noticed this unusual sight in the gulf. Not something you see every day."
Johnson was kind enough to take another shot (below): "Here's another view from the side. The shuttle mockup is enroute to Clear Lake (JSC). It arrives this afternoon."