Blackstar

The reportedly shelved Blackstar is described by Aviation Week as a military analog to the space shuttle:

For 16 years, Aviation Week & Space Technology has investigated myriad sightings of a two-stage-to-orbit system that could place a small military spaceplane in orbit. Considerable evidence supports the existence of such a highly classified system... U.S. intelligence agencies may have quietly mothballed a highly classified two-stage-to-orbit spaceplane system designed in the 1980s for reconnaissance, satellite-insertion and, possibly, weapons delivery. It could be a victim of shrinking federal budgets strained by war costs, or it may not have met performance or operational goals... This two-vehicle "Blackstar" carrier/orbiter system may have been declared operational during the 1990s... THE SPACEPLANE'S SMALL CARGO or "Q-bay" also could be configured to deliver specialized microsatellites to low Earth orbit or, perhaps, be fitted with no-warhead hypervelocity weapons--what military visionaries have called "rods from god." Launched from the fringes of space, these high-Mach weapons could destroy deeply buried bunkers and weapons facilities...

Aviation Week: Two-Stage-to-Orbit 'Blackstar' System Shelved at Groom Lake?