Ever since the famous Lockheed Skunk Works-designed SR-71 Blackbird was retired from US Air Force (USAF) service in 1989, people have been asking what would replace it. Increasingly, the answer is the SR-72 “Darkstar,” supposedly the American defense giant’s next-generation successor to the famous Mach 3 spy plane.
The most significant difference between the old Blackbird and the SR-72 is that the latter is designed as an unmanned platform. Not only is the aircraft supposedly uncrewed, but not having to ensure the survival of a human pilot makes it also capable of Mach 5 or better speeds.
It will also be a platform that does more than take long-range high-altitude surveillance photos like the SR-71. Instead, it will be a multi-mode sensor vehicle focused on intelligence, surveillance, and reconnaissance (ISR) missions. Beyond providing intelligence and other data through a sophisticated communications network, the SR-72 will also be utilized as a launch platform for hypersonic strike weapons.
In its day, the SR-71 was a revolution in its use of radar-absorbing materials (RAM), its ability to operate above 80,000 feet, and its ability to maintain supersonic speeds even in much thinner air at those altitudes. It was the first real stealth aircraft in modern combat aviation history and the first modern military aviation platform to never suffer a single combat loss.
SR-72 – New Technological Disciplines
Since the SR-71 first flew in the 1968 Vietnam War era, all the disciplines that made it possible have advanced by several generations. These are all part and parcel of the design characteristics required for an aircraft that is supposed to penetrate an enemy air defense network at hypersonic speed to carry out both ISR and strike missions.
As with most advanced combat platforms, one of the keys to the Darkstar’s previously unheard-of speed is the Turbine-Based Combined Cycle (TBCC) engine, the design of which merges turbofan and scramjet technologies. As its name implies, the TBCC design combines a turbofan and scramjet for efficient hypersonic travel.
More specifically, the TBCC is a combined-cycle design that essentially integrates four types of engines: turbine, rocket, ramjet, and precooled.
The concept for this type of engine goes beyond just the integration of differing modes of propulsion into a single power plant. Scientific and theoretical papers also discuss the design of new concepts for inlet forms. An abstract of one paper on the subject discusses “advanced mixed rectangular divergent and integrated multidimensional cross-sectional configurations being analyzed” and that “the future direction points toward the development of 3D internal contraction inlets.”
Future Air Combat Silver Bullet
The SR-72 Darkstar should make its first flight this year and enter service in 2030. As its design specifications indicate, once the aircraft is operational, it could redefine how ISR (Intelligence, surveillance, and reconnaissance) and strike capabilities are employed in high-threat environments.
The Darkstar’s operational profile is focused on leveraging the combination of its speed and extremely low signature. This will reduce time on target and permit it to evade modern air defense systems while reaching its target area.
This level of performance is also not just a theoretical construct. An increasing body of circumstantial evidence, budgetary history, the number and type of technology partners involved in the program, and non-specific comments made by Lockheed Martin officials point to the Darkstar being a real platform with concrete performance capacities.
SR-72 Son of Blackbird. Image Credit: Creative Commons.
SR-72. Image Credit: Artist Rendering from Lockheed Martin.
SR-72 Artist Rendering. Image Credit: Creative Commons.
This aircraft is not just a ” technology uber alles” effort to validate a set of advanced developmental concepts and is not a waste of funding by a long shot. Lockheed’s program manager Brad Leland has explained that “hypersonic aircraft, coupled with hypersonic missiles, could penetrate denied airspace and strike at nearly any location across a continent in less than an hour.” Any nation with this capability in its arsenal has a definite advantage over any adversary.
“Speed is the next aviation advancement to counter emerging threats in the next several decades,” he continued. “The technology would be a game-changer in theater, similar to how stealth is changing the battlespace today.”
About the Author: Reuben F. Johnson
Reuben F. Johnson is a survivor of the February 2022 Russian invasion of Ukraine and is an Expert on Foreign Military Affairs with the Fundacja im. Kazimierza Pułaskiego in Warsaw. He has been a consultant to the Pentagon, several NATO governments and the Australian government in the fields of defense technology and weapon systems design. Over the past 30 years he has resided in and reported from Russia, Ukraine, Poland, Brazil, the People’s Republic of China and Australia.
