This is an interesting story about how Area 51 was kept hidden from Soviet spy satellites during the Cold War. So how did they do it? Did they use some kind of optical camouflage? Did they have some method of distorting the view of what the satellite picked up? No, the solution was far more low tech:
Often hoisted atop tall poles for radar tests of the planes’ stealthiness, OXCART prototypes were tested outside—making the Soviet spy satellites especially aggravating.
“We had hoot-and-scoot sheds, we called them,” Barnes says in the new National Geographic Channel documentary Area 51 Declassified. (The Channel is part-owned by the National Geographic Society, which owns National Geographic News.)
“If a plane happened to be out in the open while a satellite was coming over the horizon, they would scoot it into that building.”
Former Area 51 procurement manager Jim Freedman adds, “That made the job very difficult, very difficult.
“To start working on the aircraft and then have to run it back into the hangar and then pull it out and then put it in and then pull it out—it gets to be quite a hassle,” Freedman says in the film.
That’s pretty simple and sounds pretty effective. The Soviets couldn’t see what wasn’t there after all. I find the stories of how the Americans and Soviets tried to keep secrets from one another fascinating and I think a general rule of tactics that were both simple and effective eventually sprung up.