The shuttle program has been flying for so long and done so many things that it's difficult to encapsulate the entire program on a single patch. I used the silhouette of the orbiter because it is such an iconic shape, recognizable to people all over the world. The crescent Earth depicts a similarly iconic view from orbit, while the sun can be interpreted both as setting at the end of the successful shuttle program and rising on the new program's in NASA's future. The five stars centered on the orbiter represent the 5 orbiters that have flown in space over the history of the program - Columbia, Challenger, Discovery, Atlantis, and Endeavour. These are located over the payload bay to also represent the hundreds of payloads and missions that the shuttle has supported, from experiments to satellites to space station dockings. Finally, the stars in the background represent the thousands of people who have supported the space shuttle program over the past 29 years.