That launch facility wasn't built for the space shuttle. Back in the 60s, the military was planning to use its own version of the gemini spacecraft to carry astronauts to a manned spy satellite. The project was begun because at the time, spy satellites relied on film, and getting information in an emergency often meant jettisoning the film canister prematurely, and rendering the expensive spy satellite unusable. Sending a manned mission with a human observer to determine if the photos were worth sending back seemed like a good idea. The US cancelled the program because unmanned satellites that didn't require film were on the drawing board. The Russians however did send a few military space stations into orbit. When the Shuttle entered service, the Air Force wanted to launch military cargo on its own, and tried to modify their existing launch site. This proved more expensive than planned, and the project was scrapped after the Challenger disaster.