DARPA Black Swift seeks to capitalize on lessons learned from NASP

April 1, 2008
Black Swift. Prior to the release of the President’s new budget proposal last February, it was largely rumor—most off the mark—and occasional brief references, usually followed by what amounted to “no comment” from the U.S. Defense Advanced Research Projects Agency (DARPA) in Arlington, Va.

By J.R. Wilson

ARLINGTON, Va.—Black Swift. Prior to the release of the President’s new budget proposal last February, it was largely rumor—most off the mark—and occasional brief references, usually followed by what amounted to “no comment” from the U.S. Defense Advanced Research Projects Agency (DARPA) in Arlington, Va.

Black Swift is a new joint effort by the DARPA and U.S. Air Force to develop a hypersonic aerospace vehicle capable of speeds as fast as Mach 6 while cruising at 100,000 feet or punching through the atmosphere to function as a low-Earth-orbit spacecraft. It will build on decades of research by DARPA, the Air Force, NASA and others, including Australia, which has become a world leader in hypersonics.

Specifically, Black Swift will use advances made by FALCON (Force Application and Launch from CONUS) to develop materials that can withstand the extreme heat generated by hypersonic flight for extended periods of time. Two FALCON Hypersonic Test Vehicles are planned for unmanned flights from Kwajalein Atoll in the South Pacific this year.

Lockheed Martin is the probable contractor, with Pratt & Whitney thought to be providing the engines. The likely program manager appears to be Dr. Stephen Walker, deputy director of DARPA’s Tactical Technology Office, who is already leading a DARPA/Air Force precursor effort—the High Speed/Hypersonic Reusable Demonstration—that features two elements: A High Speed Turbine Engine Demonstration (HiSTED) and a Scramjet Engine Demonstration (SED).

Walker’s only apparent public reference to Black Swift came in a largely-ignored Air Force news release several months ago: “The Falcon Black Swift flight demonstration vehicle will be powered by a combination turbine engine and ramjet, an all-in-one power plant. The turbine engine accelerates the vehicle to around Mach 3 before the ramjet takes over and boosts the vehicle up to Mach 6.”

Some speculators have called it the SR-72, a reference to the Lockheed-built SR-71 Blackbird—a Mach 3 spy plane that was retired in 1998 after nearly 35 years in service. While the designation is questionable, the implication is not. Indeed, the potential of such a platform is enormous, both military and civilian—especially since DARPA’s ultimate goal is not Mach 6, but Mach 25.

On the civil side, a Mach 25 aerospace place could carry passengers halfway around the world in less than an hour, taking off from and landing at existing major airports. A cargo version could make international package shipments nearly as fast as cross-city couriers. As a space plane, it could deliver scientists and technicians to build and operate space stations—or tourists to orbital hotels—as well as place, retrieve, and service satellites.

DARPA and the Air Force, of course, are looking at the military side of the equation—the ability to transport troops, equipment and supplies, place tactical communications and surveillance satellites, perform fly-over surveillance at a moment’s notice, and deliver precision-guided munitions to any spot on Earth in a matter of minutes, flying at speeds that would make it difficult for even the most advanced adversary to counter. This would be doing so with or without a human pilot in the cockpit.

With all that potential, then, why has DARPA been so reticent? In a word: NASP.

In the early 1980s, DARPA was pursuing a program called the National Aerospace Plane, which pretty much mirrored the description above. But NASP was a true “DARPA-hard” program, pushing every associated technology as far as was possible at the time. One of the biggest was materials—there wasn’t anything available then that could withstand those extreme temperatures (thus the extremely complex jigsaw puzzle of ceramic tiles on the Space Shuttle, a solution DARPA found unacceptable for NASP).

There were other problems, as well, of course—but that is the nature of DARPA-hard, which routinely takes on as a challenge those things the rest of the world considers impossible.

What really killed NASP, however, was not the technological challenge but the high profile it received when President Ronald Reagan became so impressed by the concept that he highlighted it in his State of the Union address. He renamed it the Orient Express to emphasize its projected ability to fly from New York to Tokyo in less than an hour, transporting at least twice as many passengers 10 times faster than the European-built Concorde supersonic jetliner.

While such high-level support may be helpful to most programs, it opens DARPA efforts, which typically are decades ahead of practical implementation, to intense attack, from politicians who face multiple election campaigns before such a program yields obvious fruit and from Pentagon budget-cutters who want to redirect the program’s money to immediate needs.

This is exactly what happened to NASP, where funding that had averaged a few hundred million dollars a year fell to almost nothing and eventually was transferred to the Air Force, which was a partner in DARPA’s effort and has had its own hypersonics research for decades, as well.

The DARPA director at the time said the problems with NASP, other than too much hype, were summed up by Ben Rich, then head of Lockheed’s famed Skunk Works: They didn’t have the high-temperature materials, the basic propellant technology, the scramjet technology, the structural efficiency to handle the required payload; in short, “we can’t get there from here.”

“We took it as far as one could, but basically materials got in our way,” current DARPA director Dr. Tony Tether says. “There were a lot of technologies that had to be done to do that, so we pushed everything as hard as we could and realized there were still a lot of fundamental things that had to be done. For the past 15 years, we’ve been working on those fundamentals—materials that can survive high temperatures, engines that can have positive thrust at zero forward velocity, yet change their mechanisms as they go through the various regimes, finally getting up to Mach 10.”

DARPA prefers to function outside the spotlight, not because its programs are classified (although some are), but because it holds a unique charter to operate at the extremes of technological capability, to do the impossible, and in pursuing that goal, to accept failure as a cost of doing business. In many ways, it follows the philosophy of Dr. Werner von Braun, who believed if everything goes exactly as planned, nothing is learned; only by examining failures are advances made.

By DARPA standards, NASP was not really a failure. They learned a great deal, especially about what they did not know, what they needed that did not yet exist. Which is why the agency continued to revisit the concept of hypersonic flight as the years passed—and why now, a quarter of a century later, a new generation of DARPA scientists believe it is time to re-examine the original concept, applying all the advances made in computer technology and materials.

Even so, building a Mach 25 aerospace plane the size of a Boeing 737 remains DARPA-hard. DARPA intends to approach Black Swift with the same combination of practicality and out-of-the-box thinking it has used to develop stealth technology, robots, artificial intelligence, advanced computers—even the mouse.

“The initial version (of Black Swift) will be unmanned, which avoids a lot of man-rating that is really more cost than technology,” Tether explains. “We’ll have an airplane that can take off, fly up to Mach 6, turn around and land again. It also will be designed to do an aileron roll at Mach 6 at 100,000 feet, which separates it from a missile.

“Mach 6 is just a step. Once we get there, we’ll be back on the NASP path, maybe a little bit more cautious in terms of time to get to Mach 25. That’s the result of a major program that has been going on called FALCON, where we’ve been developing the materials where you can have an airplane that can stand this kind of heat over a long period of time.”

Given DARPA’s history of pursuing what Tether calls “far side” technology, ultimately bringing it to the “near side” for practical implementation, and the agency’s longstanding pursuit of hypersonics, the smart money would be on Black Swift—or, more accurately, its successors.

“Our greatest crossover between aircraft and satellites is our desire to develop a vehicle that looks like an aircraft, could take off horizontally, fly into space, and come back. We’ve had that dream for a long time; you can find studies of that going back to the Sixties,” Tether says.

“When somebody says something is a great idea, but can’t be done, that makes it a challenge for us here at DARPA. Of course, we do a lot of things that don’t fit that; sometimes people will put qualifiers on it, saying maybe having an airplane take off horizontally, fly to 100,000 feet and do the roll can’t be done—at least, not more than once,” Tether continues. “Our airplane has to land and do it again and again and again. That’s what makes a DARPA-hard problem.”

Stealth, unmanned aerial vehicles that can fly half-way around the world and remain on station for a week or more, AI, superfast small computers, autonomous rendezvous and satellite servicing, space launch vehicles, even the creation of the field of seismology as a side-effect of developing the capability to detect underground nuclear tests—all examples of DARPA’s willingness and ability to continue pursuing technologies few others believe in while advancing through both success and failure.

Hypersonic flight of the type targeted by DARPA has been a lifelong pursuit, filled with small advances and very public “failures.” With the advances in technology and materials of the past decade, Black Swift undoubtedly has the best chance to date of success, by traditional measures. Realistically, it may be another two or three decades before you can have breakfast in New York, a business lunch in Tokyo, and dinner in London, all on the same day. But that day now seems likely to come long before DARPA celebrates its centennial.

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