Space shuttle was actually used for a few military launches, and did deploy military (or NRO) payload(s). If you look at a list of STS missions, the military o

Space shuttle was actually used for a few military launches, and did deploy military (or NRO) payload(s). If you look at a list of STS missions, the military ones have 'undisclosed' missions. The pentagon discontinued reliance on STS after the interruption caused by the Challenger explosion.