US unveils hypersonic spy plane concept

Classified Mayhem program to deliver SR-72 hypersonic system capable of multiple missions by October 2028

The US has commenced the development of a new intelligence, surveillance and reconnaissance (ISR) hypersonic vehicle, seen by some analysts as the successor to the vaunted SR-71 Blackbird spy plane of Cold War fame.

Last week, The Warzone reported that the US Air Force had awarded Leidos a contract with a US$334 million price ceiling aimed at “delivering a larger class air-breathing hypersonic system capable of executing multiple missions with a standardized payload interface, providing a significant technological advancement and future capability,” as stated in the contract quoted in the report.

It also notes that Leidos shall do work at the Wright-Patterson Air Base and other potential testing sites and is expected to be completed by October 2028 as part of the classified Mayhem program.

The report mentions that the aircraft will be capable of multiple missions, including delivering area effect, unitary payloads, or ISR missions. Furthermore, it says the hypersonic vehicle will be powered by a turbine-based combined cycle (TBCC) powerplant scheme.

In a TBCC design, scramjets are used for supersonic or hypersonic flight. Still, these only work well at high speeds, traditionally needing an initial boost from rockets to achieve the required airspeed to function. Using jet engines to provide the initial boost would allow such an aircraft to take off from conventional runways and reach the necessary airspeed for its scramjets to kick in.

However, The Warzone mentions that much is still unknown about the Mayhem project. For example, it is unknown whether the vehicle type will be expendable or reusable as it is being described as somewhere between a hypersonic missile and a full-on hypersonic aircraft.

Despite this ambiguity, it is plausible that the Mayhem project aims to deliver a successor to the Cold War SR-71 spy plane.

In a January 2022 article in 19fortyfive.com, Ethen Lieser mentions that Lockheed Martin has been giving hints about the development of the SR-72 spy plane, which is envisioned to fly at Mach 6 to allow ISR operations over enemy territory before their air defenses could even react.

“The SR-72 is envisioned as an unmanned, reusable hypersonic ISR and strike aircraft capable of Mach 6 flight, or nearly double the speed of its predecessor, the SR-71 Blackbird. NASA is funding the validation of a previous Lockheed study that found that speeds up to Mach 7 could be achieved with a dual-mode engine that combines turbine and ramjet technologies,” the 1945 article said.

Graphic: 1945 / Twitter

While satellites and drones may have primarily replaced spy planes since the end of the Cold War, the emergence of anti-satellite and cyberwarfare capabilities may have renewed interest in stealth supersonic manned spy aircraft.

In a July 2013 Foreign Policy article, John Reed notes that evolving threats to space assets have forced the US to re-evaluate the need for manned airborne ISR spy aircraft.

He wrote then that while the US has operated many new spy planes over decades of counterterrorism and counterinsurgency in the Middle East, the planes are slow, propeller-driven, not stealthy and unsuited for penetrating heavily defended airspace.

As such, there may be renewed US appreciation of spy planes in today’s international environment characterized by great power competition. If so, US defense branches aren’t clearly in agreement about the role of spy planes.

In an August 2020 article for Forbes, David Axe mentions that the US Army and Air Force are at odds about the usefulness of spy planes in a great power conflict.

Axe says that while the US Army deploys the non-stealth Airborne Reconnaissance and Target Exploitation Multi-Mission System (ARTEMIS) spy planes to monitor China’s naval forces in the Pacific and Russia’s forces in Ukraine at standoff distances, the US Air Force is in the process of divesting itself of all non-stealth spy planes due to vulnerability concerns in a near-peer conflict. 

The ARTEMIS, powerful as its ground-sensing radars may be, is limited to flying over friendly or permissive airspace, scanning the peripheries of China and Russia’s territories, and lacks the capability to penetrate their vast landmasses, which gives them their strategic depth.

Thus, there may still be a need for a stealthy, high-altitude supersonic spy plane that can enter and exit heavily defended airspace, which may be hazardous to even the latest stealth aircraft.

In a July 2022 Sandboxx article, Alex Hollings mentions that most nations operate radar systems that can detect stealth aircraft, such as the F-22 and F-35, and that the former lacks the means to target these aircraft. In simpler terms, this means dated air defense radars can detect stealth aircraft but shooting them down is another matter.

Similarly, Dave Majumdar writes in a July 2014 USNI News article that China and Russian radars are on track to detect the F-22 and F-35 and that the proliferation of these radars poses serious questions about the survivability of stealth aircraft. Hence, there may be renewed need for a supersonic spy aircraft like the SR-71.

In a July 2020 CNN article, Jacopo Prisco says that the guiding philosophy behind the Mach 3+ SR-71 is to have a spy plane that can fly at the edge of the atmosphere beyond the range of Soviet air defenses, fly faster than a missile and be barely visible to radar.

An SR-71 spy plane. Image: Wikipedia

Prisco notes that when an adversary detects the aircraft and fires a missile, it is already on its way out of the area. He also notes that no aircraft were lost to enemy fire due to the SR-71’s unique capabilities.

Prisco says that the SR-71 was designed before the invention of real-time data links, so it needed to take pictures on film and then return to base for the photos to be developed and analyzed. Although the SR-71 was retired in 1999 due to the advent of drones and spy satellites, the Global War on Terror provided brief incentive for the aircraft’s revival. 

In a July 2022 article for The Warzone, Stephen Walker notes that the L-52M datalink upgrades to the SR-71 could have kept it relevant, but lack of support from the US Air Force leadership, high operating costs, competition from spy satellites and the U-2 spy plane, and the dismantling of the last SR-71 trainer aircraft in 2003 conclusively ended the type’s service.

However, the rise of China and the resurgence of Russia as near-peer competitors underscored the need for a spy aircraft along the lines of an improved SR-71 that relies on altitude and extreme speed to evade enemy defenses for ISR missions. 

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