DARPA’s Hypersonic Cruise Missile Flew Its Final Test, Follow-On To Come

DARPA announced today that the HAWC program had come to a close after an early January flight test of the Lockheed Martin and Aerojet Rocketdyne offering, with the latter company having produced the missile’s scramjet engine. A rival HAWC design from Raytheon and Northrop Grumman, which achieved a successful free-flight test in September 2021, has also been tested as part of the HAWC project. 

A corresponding Lockheed Martin press release explains that the missile was launched from a B-52 Stratofortress bomber, as was the case with an earlier flight test of the company’s HAWC design announced last April. During this month’s test, the HAWC system’s booster stage first accelerated it to a high speed. The Aerojet Rocketdyne scramjet engine then took over, propelling the missile at a speed over the Mach 5 hypersonic threshold. The missile then flew higher than 60,000 feet and farther than 300 nautical miles, according to DARPA. 

“The HAWC program created a generation of new hypersonic engineers and scientists,” said Andrew ‘Tippy’ Knoedler, the HAWC program manager. “HAWC also brought a wealth of data and progress to the airbreathing hypersonic community. The industry teams attacked the challenge of scramjet-powered vehicles in earnest, and we had the grit and luck to make it work.”

“We had our share of difficulties,” Knoedler added. “Through a pandemic, a strained supply chain, and atmospheric rivers, our industry partners forged ahead, mitigating the risks where they could and accepting others. They delivered on their promises, proving the feasibility of the concept.”

Lockheed Martin’s role in DARPA’s HAWC program began in 2018 when the company was awarded a $928 million contract by the agency and the Air Force to develop its version of the hypersonic cruise missile. While Lockheed Martin initially proposed its design as a land-attack capability, the company has since pitched a maritime strike variant of the concept to the U.S. Navy with the idea that it could potentially be launched from F-35C stealth fighters among other platforms. 

The Aerojet Rocketdyne scramjet engine used by Lockheed Martin’s HAWC missile has been key in ensuring that the weapon will be able to maintain hypersonic speeds between Mach 5 and Mach 10 while in flight. Even still, details about both Lockheed Martin/Aerojet Rocketdyne’s and Raytheon/Northrop Grumman's HAWC designs remain limited.

Sharing similar ambitions as other hypersonic weapon development programs in the U.S., HAWC envisions providing the U.S. military with a capability that can strike a critical target from significant stand-off distances at very high speeds and on short notice. HAWC has been especially focused on maturing technologies, like scramjet engines, that would go into future air-breathing hypersonic cruise missile designs. 

While capabilities like HAWC are much closer in form and function to existing cruise missiles, namely supersonic ones, these hypersonic weapons will travel at higher speeds while still being able to maneuver through the atmosphere, making it very difficult for adversaries to defend against them.

DARPA has made it clear from the very beginning that both Lockheed Martin's and Raytheon's designs are just stepping stones in the Air Force’s larger push toward developing a fieldable air-breathing hypersonic cruise missile. Now that DARPA’s HAWC project has completed its final test, the agency plans to continue maturing that technology under the aforementioned follow-on program it has dubbed MoHAWC.

“Those missiles will expand the operating envelope of the scramjet and provide technology on-ramps for future programs of record,” read the DARPA press release. 

Fiscal Year 2023 (FY23) budget justification documents explain that efforts under the MoHAWC program, which DARPA is requesting $60 million for, will include, “advancing hydrocarbon scramjet-powered propulsion operation, shrinking navigation components, upgrading aircraft integration algorithms, and improving manufacturing approaches.” The document goes on to say, “Flight tests will expand the operational envelope. This program will collaborate with Navy and Air Force science and technologies efforts to meet future technology insertion dates for service programs of record.”

The budget documents also list specific FY23 goals for the MoHAWC project, which include incorporating HAWC lessons learned into the cruiser design; initiating procurement of long lead components for four flight test systems; completing the subsystem technology risk reduction efforts; and beginning assembly, integration, and ground testing of cruisers. While the term ‘cruiser’ in this context is a bit nebulous, it could point to a more robust air-breathing hypersonic capability, in this case, most likely a cruise missile design.

A separate Air Force hypersonic weapon initiative known as Project Mayhem, which is aimed at delivering a larger class air-breathing hypersonic system capable of executing multiple missions, has also used this language in explanations of the program. In an interview with Aviation Week, the Air Force specifically described Mayhem as a ‘Multi-Mission Cruiser’ because of the program’s early “focus on sustained hypersonic flight capabilities independent of potential payloads,” but it's unclear what the relationship might be between Mayhem and HAWC if any at all.

Other ongoing hypersonic development projects in the U.S. military include one Navy effort centered on the development of a hypersonic anti-ship missile called Screaming Arrow and another known as the Hypersonic Air-Launched Offensive Anti-Surface Warfare (HALO) missile, which the service hopes to field no later than 2028. The Air Force and Lockheed Martin’s criticized AGM-183A Air-launched Rapid Response Weapon (ARRW) adds to the list, as well, and has been expected to be America’s first operational air-launched hypersonic weapon. It completed a successful test last December, although what's to come in its future is a little murky at this time.

On top of that, HAWC is expected to feed into the Air Force's own Hypersonic Attack Cruise Missile (HACM) project. HACM is yet another Defense Department program with the goal of developing an air-launched, air-breathing hypersonic weapon, and a Critical Design Review of the missile is currently scheduled to occur by sometime next summer. 

The increased interest in hypersonic development spans the Defense Department, ranging from the Army’s ground-launched Dark Eagle hypersonic weapon to the Navy’s push to arm its Zumwalt stealth destroyers with hypersonic missiles from the service’s related Conventional Prompt Strike program. Each effort mentioned underscores just how important developing and ultimately fielding a hypersonic weapon has become for the U.S., and testing infrastructure is expanding as a result. Also, keep in mind that these are just the programs we know about, there are certainly others that exist under deep classification at this time.

Russia and China have been actively progressing on their own hypersonic missiles of various types as of late, which some argue only emphasizes the need for the U.S. to establish such a capability. There has been criticism that the U.S. might be falling behind Russia and China, who both claim to have already fielded various hypersonic weapons. In fact, Russia just recently insisted that Admiral Gorshkov, which was at the time reported to be somewhere in the Atlantic, is currently armed with Zircon hypersonic cruise missiles. Just how capable or ready for battle those missiles may be is unclear at this time.

Proponents of hypersonic weapons development argue that they will be key capabilities for the U.S. in a future high-end conflict. With DARPA having completed the HAWC program, opening the door for the maturation of the technology under the new MoHAWC project, it would seem the U.S. military is at least one step closer to meeting such a need. 

Contact the author: emma@thewarzone.com