China’s hypersonic cooling innovation puts heat on US

China’s latest hypersonic cooling technology breakthrough marks a significant leap forward in the race to dominate global high-speed flight and missile systems.

This month, the South China Morning Post (SCMP) reported that a Chinese military research team, led by assistant researcher Li Shibin from the National University of Defence Technology, has developed an innovative cooling device capable of managing the intense heat generated during hypersonic flight.

The SCMP report says that the device operates for up to 2.5 hours and is a crucial advancement for long-duration, high-speed missions, allowing for journeys from one side of the Earth to the other. The team’s invention is detailed in the Journal of National University of Defence Technology.

SCMP says that the cylindrical cooling system utilizes the thermal energy from aerodynamic heating to drive an active cooling cycle, ensuring the proper functioning of critical components under strenuous flight conditions.

It mentions that China’s race to develop hypersonic capabilities, alongside the US and Russia, has led to test flights of long-range hypersonic unmanned aircraft, with plans for crewed global flights by 2035.

In addition, the report points out that China unveiled the DF-17, the world’s first hypersonic glide missile, in 2019. Recent US Army tests of a similar weapon highlight the rapid progress in this field.

However, as a US congressional investigation noted last year and the SCMP points out in its report, managing the extreme heat generated in hypersonic flight remains a fundamental challenge.

SCMP reported that Chinese scientists are advancing hypersonic weapon technology with a new HGV capable of exceeding Mach 15 speeds. This vehicle utilizes a “skipping stone” trajectory for extended range and maneuverability.

SCMP notes that the science team, led by Yong Enmi from the China Aerodynamics Research and Development Centre, aims to surpass the foundational work of Qian Xuesen, the “father of Chinese rockets,” who conceptualized hypersonic gliders in the 1940s.

It notes that these gliders, exemplified by China’s DF-17 missile, can penetrate air defenses with unprecedented speed and agility.

The SCMP report says the latest design, outlined in a June article in the Chinese Journal of Astronautics, includes a solid-fuel booster capable of multiple ignitions. It mentions that the design enables the HGV to maneuver in and out of the atmosphere and extend its kill range by more than a third.

SCMP notes that this development could shift the primary use of hypersonic gliders from regional to global operations. However, it points out that while the technology is not yet combat-ready, additional systems for flexible trajectory adjustments are required.

The report also highlights that the new aircraft’s design, which integrates the fuselage with wings and features novel algorithm trajectory optimization, has shown potential in simulations to maintain speeds above Mach 17 for extended periods, suggesting the capability to strike almost any global target.

As China accelerates its hypersonic technology, the US grapples with detecting and defending against these rapidly evolving threats.

In a June 2024 report, the US Congressional Research Service (CRS) noted hypersonic weapons’ agility and low-altitude flight capability could challenge current detection and defense systems.

Terrestrial-based radars often struggle to detect hypersonic weapons until late in flight because of their limited line of sight. This deficiency, the CRS report says, leaves defenders with little time to launch interceptors to stop the incoming weapon.

US defense officials have reported that the current sensor systems on land and space are ineffective in identifying and monitoring hypersonic weapons, according to CRS. Former undersecretary of defense for research and engineering Mike Griffin says hypersonic targets appear 10 to 20 times dimmer than the objects typically tracked by US satellites in geostationary orbit, as quoted in the CRS report.

Although the US is accelerating its hypersonic weapons program, it faces challenges addressing the intense heat generated during hypersonic flight.

This month, the CRS highlighted the significant challenge of heat control and thermal management in hypersonic flight, where vehicles travel at speeds exceeding Mach 5. The CRS report mentions that at such extreme velocities, the friction between the vehicle’s surface and the atmosphere generates intense heat, necessitating advanced thermal protection systems.

The report mentions that the US has built new hypersonic test facilities to find solutions for those thermal challenges, such as the University of Notre Dame’s Mach 6 and Mach 10 quiet wind tunnels and Purdue University’s Mach 8 quiet wind tunnel. It also mentions plans for constructing a kilometer-long Mach 10 wind tunnel at Texas A&M University in partnership with Army Futures Command.

While the US builds cutting-edge test facilities to tackle the intense heat of hypersonic flight, its hypersonic weapons program has been criticized for overlooking critical design and transparency issues in its rush to deploy the advanced weapons.

In a critical evaluation of the US Department of Defense’s (DOD) hypersonic weapons development, the US Government Accountability Office (GAO) released a report in July 2024 highlighting several challenges.

The GAO found that the DOD’s focus on rapid delivery has often overlooked the integration of user feedback and modern digital engineering tools, which could enhance design efficiency and reduce costs.

The GAO report also underscored the difficulty in estimating costs due to limited historical data, with programs like the Navy’s Conventional Prompt Strike (CPS) relying heavily on expert opinions, potentially introducing bias.

Furthermore, the GAO noted a lack of transparency with the US Congress regarding enterprise-level risks and progress in fielding hypersonic systems.

Amidst criticism directed against the US’s rushed and opaque hypersonic development, a new partnership with Australia aims to bolster defenses and counter the growing hypersonic threat from China and Russia.

Reuters reported this month that Australia and the US are advancing toward joint production of hypersonic missiles, as revealed by US Republican lawmaker Michael McCaul during a visit to Sydney.

Reuters mentions that McCaul, who chairs the US House Foreign Affairs Committee, highlighted the strategic partnership’s potential to alleviate pressure on the US defense industrial base and enhance regional security against emerging threats.

The Reuters report says the collaboration, spurred by China’s hypersonic tests in 2021 and Russia’s use in Ukraine, aims to enable Australia to counter rapid strikes. McCaul notes that current defenses cannot intercept a Chinese hypersonic attack.

Reuters points out that the initiative aligns with the AUKUS alliance’s goals, which include transferring nuclear-powered submarines to Australia and jointly developing cutting-edge defense technologies.