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The Lockheed D-21, a Mach 3.3 Drone intended for launch from the SR-71 Blackbird : r/EngineeringPorn
![NRO on X: "The NRO, as part of its continuing document declassification and release program, has released 97 records associated with the D-21 Tagboard project. The project, a supersonic reconnaissance drone, was NRO on X: "The NRO, as part of its continuing document declassification and release program, has released 97 records associated with the D-21 Tagboard project. The project, a supersonic reconnaissance drone, was](https://pbs.twimg.com/media/D2RJuJzWkAAIUqI.jpg:large)
NRO on X: "The NRO, as part of its continuing document declassification and release program, has released 97 records associated with the D-21 Tagboard project. The project, a supersonic reconnaissance drone, was
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