“It’s been almost 20 years since the SR-71 was retired. If there was a replacement, they’ve been hiding it pretty well,” says Brad Leland, Lockkheed Martin's portfolio manager for air-breathing hypersonic technologies, quoted in Guy Norris' breakthrough story on the SR-72.
Very true. 20 years ago, I and a bunch of other smart and occasionally eccentric individuals, Guy included, spent a lot of time trying to track down that SR-71 replacement, and (if it existed) it was indeed hidden very well. Mind you, those responsible for hiding secret projects had a few advantages over us, including the services of unfriendly men carrying M-16s, the authority to turn large pieces of the Mojave into use-of-deadly-force-authorized no-go areas, and the resources to forge quite convincing documents that linked Area 51 to re-engineered spacecraft and dead aliens.
Indeed, if someone hasn't hidden quite a few aircraft programs very well, the taxpayer is owed a confession and a refund, because there are a few things in this murky story that are clear beyond a doubt.
Starting in the 1980s, a ramshackle desert encampment that lay almost dormant between major programs turned into Edwards East, capable of supporting multiple concurrent flight test programs. Classified project funding waxed fat and stayed that way in the 1990s. Ad hoc charter flights were replaced by a small airline that could haul at least 1,000 people per day from Las Vegas to Area 51 (augmented by on-base enlisted people and bussed-in civilians).
The only function of this base and its elaborate and costly security is to flight-test aircraft that are secret, and visibly different from other aircraft in ways that point to unique characteristics - as was the case with the U-2 and A-12/SR-71 family and the first stealth programs. Once these programs grew large they became a security risk: too many people, and too big to be shut down when something else was flying. They were moved out.
This secret mountain has produced, if not a mouse, exactly two declassified programs since Northrop's Tacit Blue: the Boeing Bird of Prey and Lockheed Martin's RQ-170 Sentinel. When the Tacit Blue requirement was drafted, Gerald Ford was president. So some things must have been kept secret or we have all been ripped off.
One of those things was a high-speed vehicle.
Of all the evidence that came to light in the course of the media/amateur investigation of Area 51, two pieces stand out: the 1989 sighting of an unidentified aircraft over the North Sea, and the sonic booms that created a small sensation in the Los Angeles area in 1990.
The background to the "mystery booms" is worth recounting. Seismologists at CalTech had recently finished networking the sensors distributed around the area. Out of curiosity, they began using those readings to plot the tracks of Space Shuttle landings at Edwards; only after that did they check on the unexplained "skyquakes", finding similar tracks. Although the researchers eventually accepted the USAF's contention that the booms were caused by fighters operating off the coast, one of the nation's leading sonic boom experts, Domenic Maglieri, has rejected that explanation.
There's one big, interesting common feature to both these pieces of evidence: they are plausible as failures of operational security (OPSEC).
Aircraft identification experts like Chris Gibson are very rare in the U.S. The idea that there might be a trained observer in the middle of the North Sea, looking up at the right moment, is one that OPSEC might well have missed.
The CalTech seismologists, by putting their sensors on the net, had created a kind of acoustic radar. There was no reason that the OPSEC team on any secret program would know about this.
By the way, one of the things that nobody in the unclassified world knew in 1990 was that, 25 years earlier, the CIA had been hard at work on an SR-71 replacement that would not merely poke along at Mach 6 - it would reach Mach 20 in a boost-glide trajectory. It was no paper study: its engine was designed, built and tested. And guess what the planform looked like?