[link to revelationawaitsanappointedtime.blogspot.com]

"The 15th shuttle mission, STS-51-C, was the first to be completely dedicated to a secret mission for the Department of Defense. The details are still largely classified, but one alleged story leaked to Aviation Week is that one of the purposes of the mission was to launch an ELINT spy satellite in geosynchronous orbit.

More top-secret missions followed in quick succession: STS-51-J, STS-27, STS-28, STS-33, STS-36, and STS-38. And then something strange happened. After STS-53, the CIA/DoD stopped commandeering shuttle flights for classified national security purposes. Whatever it was they had been doing, had they had enough and didn't need any further surreptitious skulking in space? That hardly seems like them. But from 1992 on, the Pentagon seemingly had no further need for the Space Shuttle's services. And I asked myself once again, what do they know that we don't?"