Chapter 11: Mining the ‘far side’ of technology to develop revolutionary aircraft prototypes: the Defense Advanced Research Projects Agency (DARPA) approach – Innovation in Aeronautics


Mining the ‘far side’ of technology to develop revolutionary aircraft prototypes: the Defense Advanced Research Projects Agency (DARPA) approach

J.R. Wilson,     Freelance writer, USA


The US Defense Advanced Research Projects Agency (DARPA) was created in response to the Soviet Union’s surprise launch of Sputnik I, tasked with helping America catch up with and then surpass the USSR in space. As that and other early missions shifted to NASA and other agencies, DARPA became the means not only to prevent future technology surprises, but to create such breakthroughs itself – with a growing emphasis through the years on aerospace and pushing the aeronautics envelope, often beyond what their military customers thought they wanted. ‘Impossible’ was redefined as DARPA-hard, and ‘innovation’ as turning ‘far side’ concepts into combat-ready reality, all from a unique ‘freedom to fail’ research and development model.

Key words

Defense Advanced Research Projects Agency (DARPA)


unmanned aerial vehicle (UAV)


experimental evaluation of major innovative technologies (EEMIT) aircraft

programmable matter


in-flight shape morphing

11.1 Introduction

When the Defense Advanced Research Projects Agency (DARPA) was set up within the US Department of Defense on 7 February 1958, it had three primary purposes: first, to get ahead of the lead the Soviet Union had grabbed in space with the recent launch of Sputnik 1, and, second, to develop technologies to detect Soviet nuclear tests, regardless of size, type or location. Both of those responsibilities soon passed on to other agencies, such as the also newly created NASA.

It was the third mission that was retained and that led to DARPA becoming the world’s premier developer of cutting-edge technologies; and in so doing created one of the most unusual, perhaps unique, laboratories in the world. Essentially, it was tasked with never again allowing the US to be taken by technological surprise, and to do this by becoming the source of all future military technological surprises in the world. It was not long before the advantages of this approach crossed over to civilian applications, especially in aerospace.

11.2 Defense Advanced Research Projects Agency’s (DARPA) philosophy and structure

In order to accomplish its goals, DARPA was given a rare freedom (one that commercially aligned industry cannot support), and that was the freedom to fail. It also was given an unheard-of structure. It had no dedicated laboratories; there were no permanent research employees, nor were there permanent programs. It was not required to be ‘revenue positive’. Directors were, and still are, appointed for terms of two to four years, program managers for three to four, after which all such appointees leave DARPA to pursue careers elsewhere in government, industry or academia.

Stephen Welby, former director of DARPA’s Tactical Technology Office, said in an interview,

‘They (project managers) are all temporary hires. They are here to get something done. The clock is ticking and there is personal pressure to advance the state of the art on very aggressive timelines. You can change rapidly and move quickly when 25% of your people change out every year. You would never want to run a business this way, but for preventing technological surprise and being the engine of innovation – it’s perfect.

‘We start a lot of things, but we also ruthlessly kill them. It’s acceptable to fail as long as we have learned from it. If it succeeds, we get the data; if it fails, we find out it’s a path not to take. A project is something with a defined start, defined finish and clearly defined objectives. Something that can be written on a single piece of paper. [The goal is to] prove the feasibility of a concept and take the specific technology risk off the table… I think almost everything we do transitions. Even those that fail leave behind an industrial base or an aerodynamic database that can be used.’1

Each new director is given total freedom to choose the concepts they wish to pursue and hire program managers to do so. While any programs created by a predecessor are allowed to continue until the project manager’s tenure ends, a new director has no responsibility to continue that line of research. They can, however, reach back and resurrect previous DARPA programs, usually in the event that something has changed, such as new materials, new technologies or new theories, to advance it beyond what had been hitherto possible.

Neither DARPA nor its directors and program managers are under any mandate to pursue specific or even broad areas of research, but are free to decide if they want to concentrate on space systems, aeronautics, communications, weapons, directed energy or something seemingly pulled from the pages of science fiction. As a result, during its more than half a century of work, DARPA has been the originator or primary developer of stealth aircraft, unmanned aerial systems and hypersonic flight, to name but a few.

11.3 DARPA and innovation in aviation

‘In aviation, it’s easy to talk about most of the achievements of the past, but a lot harder to talk about the dreams of the future, because we do a lot of black programs,’ noted former DARPA director Dr Tony Tether (2001–9). ‘We were created to prevent technological surprise, but we’ve also become the place that creates technological surprise for other people.’2

Most directors have had at least a few programs designed to advance some area of aeronautics. In typical DARPA fashion, however, few end-game advancements were completed by the same director under whom they began. In some cases, such as stealth, the research advanced through multiple programs, often widely spaced in time.

Tether was the lone exception to the rule on short directorship appointments, heading DARPA throughout President George W. Bush’s two terms, from 18 June 2001 until 20 February 2009. It was Tether who began calling DARPA’s efforts ‘Far Side’ research, another way of saying ‘DARPA-hard’.

Tether’s special assistant for space, Richard McCormick, summed up the concept at DARPATech 2005, an annual gathering of DARPA program managers and interested stakeholders from across government, industry and academia. ‘First, is it DARPA-hard? That is, does it present a high chance of failure?’ he said of how DARPA looks at a new research proposal.

‘Forget the sure bets; that’s not our business. If it’s not DARPA-hard, let someone else do it.

‘Conventional wisdom leads so many space program managers to be risk adverse. In DARPA, we welcome risk; without it, we will not provide the war-fighter with the options and capabilities needed in this uncertain world. The problem isn’t when you try and fail. The problem is when you fail to try.’3

While his remarks came from a space research perspective, they apply to DARPA across the board. And, often, some of the most difficult programs to pursue – technologies the presumed beneficiaries often dismissed as unnecessary, impractical or simply impossible – were aeronautical issues that led to some of DARPA’s greatest successes. Tether said in an interview for this book:

‘DARPA’s real role is to show something can be done. I’ve found that is a very powerful thing – once you show people who don’t believe it can be done that it can, it’s amazing how much progress can be made. It removes the restraints of thinking “why waste money on this, it can’t be done”.’

11.4 Examples of DARPA innovation in aviation

‘Since the 1980s we’ve put a lot of effort into vehicles that can take off and land vertically, but fly at high speeds, sort of morphing between a helicopter and a more fixed wing approach during the cruise phase. We also took on very low radar cross-sections – stealth – not just radar, but all sensors. That started in the early 1970s and has been going since. In engine technology, we have been involved with developing engines that were good through many different stages, from subsonic to supersonic to hypersonic. Our dream has always been to have an airplane that can take off horizontally, fly into space and return.

‘DARPA’s been the leader in aviation in the sense of having really developed the UAV business, starting in the Sixties and continuing ever since, progressing UAV capabilities from vehicles that had small range and limited endurance to vehicles with extremely high range and endurance today. Global Hawk and Predator are probably the most well known. We’re still pushing that envelope further, to develop vehicles that can stay up for five years. Our latest effort is an unmanned vehicle that would be used like a satellite – you launch it and it never comes back. When you’re finished with it after five years, you just dump it in the ocean, as you would a satellite.’ (Wilson, citing, Tether)

Although its early emphasis was on space, nuclear test detection and ballistic missile defense, DARPA’s wide-open mandate also allowed its directors to focus some of their research toward other technologies. Chief among those was flight – manned and unmanned, fixed wing and rotor, across a broad range of capabilities and potential missions. And, while it obviously is focused primarily on military requirements, much of what comes out of DARPA has significantly changed civilian aviation, just as the military ARPAnet morphed into the global civilian internet.

‘Over the years, from director to director, some have thought unmanned was more important than stealth and vice versa, but I don’t think anybody has ever come in and said aeronautics as a whole is not important,’ Tether said.

Former DARPA Director George Heilmeier (1975–7) is perhaps best known as the inventor of the liquid crystal display (LCD) while working for RCA Laboratories in 1964. However, Heilmeier has said he considered the work he did on stealth technology while at DARPA to have been the highlight of his career. The program was called Have Blue, a proof-of-concept aircraft built for DARPA by Lockheed and made more difficult by an astonishingly tight two-year deadline.

Designed solely to demonstrate stealth capabilities and with no concern for aerodynamic performance beyond being able to fly, Have Blue met its deadline with its maiden flight in 1977. Only two years later the first operational aircraft to fully incorporate stealth technology made its maiden flight – the then super-secret F-117 Nighthawk Stealth Fighter. Included among those technologies, which provided the foundation for subsequent stealth programs, were the use of a multifaceted surface, radar-absorbent materials, infrared shielding, heat dissipation, low probability-of-intercept radar, active signature cancellation, shielded inlets and exhausts (along with exhaust cooling) and special windshield coatings.

Robert Fossum, DARPA’s director at the time (1977–81), noted it was not only the prospective user of such new technologies the agency had to convince, but also the contractors the agency used to create their new realities. Most of the traditional concerns in the creation of an aircraft – varying according to the focus technology, but including engines, structure, flight dynamics and even the inclusion of safety engineers in the design process – can actually make the process too complicated to succeed.2

In the case of stealth, for example, Fossum ordered his contractors to ignore everything not directly related to his narrow focus on radar cross-section. As a result, Have Blue was a heavily compromised, aerodynamically inefficient and unsophisticated aircraft – but one that achieved its DARPA-hard goals in record time. It was a significant demonstration of Fossum’s belief that successfully developing advanced technologies – DARPA-style – means single-minded focus on one goal, while giving all other concerns only the minimal attention required.

‘Stealth is another DARPA creation, because we had some people who believed they could design and fly an airplane using Maxwell’s equations and not Navier-Stokes, which basically would minimize reflection back to the source and still have enough aerodynamic features that it could fly,’

Tether explained.

‘DARPA did that over the opposition of the Air Force, who understood the value of stealth, but it didn’t have the performance of airplanes in the 1970s.

‘It was a hard cultural shift – yet they not only have made it, but today the F-22 is not just stealthy but extraordinarily maneuverable, because we have learned how to use both Maxwell’s equations and Navier-Stokes to build aircraft. So DARPA really led the way on stealth in the early days, but the Air Force took over in the mid-1980s and has carried it since then.’2

Although Have Blue was not among them, from the beginning DARPA pushed the boundaries of aeronautics through a series of X-planes – flying testbeds used to transform theory to fact for high-risk, high-payoff technologies. While not intended to be prototypes for any specific platform, they provide necessary breakthroughs in aviation design that would be difficult, if not impossible, for any other organization to accomplish. Since its inception, DARPA has been the driving force behind more than half of the nation’s X-plane programs – typically, the most Far Side technologies with the highest risks, but potentially the highest payoffs, as well.

‘Throughout its … history, DARPA has been involved in aviation development. In fact, if you wanted a glimpse into the proverbial crystal ball of aviation, you only had to take a look at what DARPA was doing,’ Van Olinger, a DARPA program manager at the time, told DARPATech 2004. ‘DARPA has been involved with both manned and unmanned X-planes. These revolutionary aircraft demonstrated significant advances in aerodynamics, propulsion, structures and flight controls.’4

11.5 DARPA’s aviation-related programs

On a decade-by-decade basis, DARPA’s aviation-related programs are described below.

11.5.1 1990s

• Joint Unmanned Combat Air Systems – Air Force X-45, Navy X-47,

• A-160 Hummingbird rotary UAV,

• Affordable Short Takeoff/Vertical Landing (ASTOVL), later renamed the Common Affordable Lightweight Fighter technology demonstration program, precursor to the F-35 Joint Strike Fighter,

• Schottky IR Imager for the B-52 (replacement for the AAQ-6),

• Materials Technology for the F-22,

• X-50 Dragonfly canard-rotor wing, with rotor stopping in flight to create a fixed wing capable of high-speed flight,

• Technology for Transport Aircraft,

• X-31 Experimental Evaluation of Major Innovative Technologies (EEMIT) aircraft, featuring integration of conventional aerodynamic control with multi-axis thrust vectoring, post-stall flight, tailless flight at supersonic speed, advanced helmet-mounted display to improve pilot situational awareness, digital fly-by-wire flight controls and significant advances in high-angle-of-attack,

• Programmable matter – smart material that adapts to changing conditions to maintain and optimize new adaptable functionality, such as an airplane wing that adjusts surface properties in reaction to environmental variables.

11.5.2 1980s

• Stealth Fighter,

• Tacit Blue (Whale) Stealth Bomber testbed, new stealth approach leading to B-2 Bomber,

• Joint STARS,

• X-29 Forward Swept Wing Aircraft Technology,

• Pilot’s Associate,

• Materials Technologies for the F-15 and F-16,

• Low Probability of Intercept Airborne Radar,

• Teal Rain high-altitude, long-endurance, extended-range ISR/Target Acquisition UAV,

• Condor long-range UAV, all-composite honeycomb structure, autonomous controls, high-altitude aerodynamics, fuel-efficient propulsion system – considered Global Hawk conceptual prototype,

• X-wing Rotor Systems Research Aircraft,

• No Tail Rotor (NOTAR) helicopter.

11.5.3 1970s

• Materials technologies for the SR-71,

• Mini-RPV.

11.5.4 1960s

• Navy Drone AntiSubmarine Helicopter (DASH).

Some of those programs transitioned to the military for development as real platforms and systems, others set the stage for later DARPA and other research efforts, and some were shelved for one reason or another, because the enabling technologies were not yet available, military requirements had changed or the theory in question failed to prove out.

11.6 Conclusions

‘It is the freedom to fail that gives [DARPA program managers] the boldness to go for the big payoffs. And fail we do!’ Tether told DARPATech 2007. ‘But that’s OK – failure sometimes happens when you’re bringing new capabilities into reality; you only really fail if you don’t learn what happened and stop trying to succeed. You have to try again – and again – and again.’5

Despite tightening federal and corporate budgets, especially for extreme cutting-edge research and development, DARPA has entered its second halfcentury continuing to resist pressures for more conventional, short-term research. For DARPA, the Far Side of miniaturization, multi-year flight endurance, hypersonic speed, in-flight shape morphing and revolutionary aircraft designs remain primary, pushing both military and civilian aerospace stakeholders to envision futures still considered the realm of science fiction.

‘Without DARPA, a lot of things might not have come about as fast. The whole idea of UAVs that could fly very high and stay up a long period of time, for example. And stealth was something the Air Force didn’t believe could be done. A lot of engine technology, such as the concept for the JSF (F-35 Joint Strike Fighter) engine, was a DARPA program,’

Tether concluded.

‘Most of what DARPA does gets lost, in terms of DARPA’s role, often because those who did it aren’t around DARPA when it becomes a success.’

11.7 References

1. Warwick, G., Norris, G., DARPA at 50: Blue sky thinking. Aviation Week. 2008. [18/25 August 2008].

2. Wilson, J.R., Fifty years of inventing the futureAerospace America. DARPA 50th Anniversary Supplement, 2008. [February 2008].

3. McCormick, R., Closing remarks. Proceedings of DARPATech 2005 Symposium, 2005. Anaheim, CA, 7–11 August 2005 Available at.

4. Olinger, V., The future of aviation. Proceedings of DARPATech 2004 Symposium, 2004. Anaheim, CA, 9–11 March 2004 Available at.

5. Tether, T., Opening remarks. Proceedings of DARPATech 2007 Symposium, 2007. Anaheim, CA, 6–9 August 2007 Available at.