Article Summary and Key Points: The SR-72 Son of Blackbird is Lockheed Martin’s next-generation hypersonic aircraft, designed to replace the legendary SR-71.
Key Point #1 – Expected to reach speeds of Mach 6, the aircraft will utilize a combined-cycle propulsion system, pairing a turbine jet engine with a scramjet for hypersonic flight.
Key Point #2 – Built with advanced titanium and ceramic composites, the SR-72 will also feature stealth capabilities and carry hypersonic missiles like the High-Speed Strike Weapon (HSSW).
Key Point #3 – While initial flight tests were rumored for 2025, details remain classified. If successful, the SR-72 will be a critical asset for the U.S. Air Force, maintaining air superiority in future conflicts.
That 1 Problem: There is that Top Gun: Maverick perception that needs to go away.
SR-72 Son of Blackbird: The Hypersonic Spy Plane of the Future
Rumors have become a cottage industry since the retirement of the SR-71 in 1989. Many wonder about a replacement for the aircraft that would signal a generational leap in technology.
Along with stories about a secret UFO base and extraterrestrials, a project called “Aurora” was said to be the supersecret successor to the Blackbird.
There is an actual program called SR-72, and Lockheed Martin is developing it at the famous Skunk Works Advanced Products Division (APD). However, one might want to be informed about what it is not before talking about what it is.
Sorry, This Isn’t Top Gun: Maverick SR-72
It is not anything at all like the Darkstar vehicle seen in the Top Gun: Maverick film.
A Mach 10 vehicle of that configuration is more sci-fi than something that could be developed in the present day to begin with.
The other reality is that the United States Air Force (USAF) would never let the US Navy run a program of these dimensions. Hypersonic vehicle designs are clearly the territory of the USAF.
Many of the details of the SR-72 “Son of Blackbird” program, as it is being called, are classified. What is known is that the program was initially proposed by Lockheed Martin (LM) in 2013 and is currently being developed at the APD.
Its maximum speed is more on the order of Mach 6.0. That’s roughly 4600 mph or almost double the speed rating for the SR-71.
Operational Details
Besides the aircraft’s speed, it is also supposedly designed—like the SR-71—to operate at altitudes exceeding 80,000 feet and have an operational range of over 3000 miles.
The propulsion system will be a combined-cycle engine with a turbine jet engine for supersonic operation and then a scramjet to power the aircraft for hypersonic flight.
Lockheed Martin is said to be cooperating with Aerojet Rocketdyne, which is a division of L3Harris, for the development of a turbine-based combined cycle (TBCC) propulsion system to enable the aircraft to achieve a cruise speed of Mach 6.
A significant challenge will be the design of a single inlet nozzle for both engines, given that they require significantly different types of airflow.
The materials for the aircraft’s construction demonstrate more than a one-generational advancement in this area of aircraft design and construction. Twin requirements include being stealthy and still surviving the intense heat of the aircraft’s surface when traveling at Mach 3 or greater speeds.
To accomplish this feat, the aircraft is supposedly constructed of titanium in high-heat and load-bearing areas to handle the stress. Other sections are composed of ceramic and carbon-carbon composites to survive the high temperatures the aircraft will be subjected to.
The turbine blades and other sections of the propulsion system will also rely on ceramic materials in order to survive the combustion chamber’s intense heat.
Unlike the SR-71, this aircraft will be armed and will reportedly be capable of firing hypersonic missiles. One example would be the LM High-Speed Strike Weapon (HSSW).
Technology Questions Remain on SR-72
The type of fuel the aircraft will use remains a major issue. The most logical choice is the JP-7 grade fuel or something even more exotic in order to achieve the speeds and fuel consumption requirements. One of the aspects of that fuel was that it had a high flash point, which was key to keeping the aircraft safe at high speeds.
A single-engine prototype aircraft was supposed to begin testing in 2025, but there is no confirmation at present. The aircraft, despite its high cost, is critical to the mission of penetrating enemy airspace and being able to launch on targets before it can be detected.
As more than one publication has pointed out, the SR-72 is supported by the USAF’s long-term “hypersonic roadmap,” which means the program will continue in order to keep pace with Russian and Chinese programs in this class of weapon system.
SR-72 Artist Rendition Photos
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.
About the Author: Reuben F. Johnson
Reuben F. Johnson is a survivor of the February 2022 Russian invasion of Ukraine and is now 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.
