US Navy Tests Hypervelocity Projectiles to Strengthen Indo-Pacific Air Defence

The United States is accelerating the development of integrated, multi-domain capabilities to support layered defence against what it sees as an exceptionally demanding threat environment. This combines drones, cruise missiles, ballistic threats and, increasingly, high-speed delivery systems. In the Indo-Pacific, the drive is closely tied to pressure exerted by China across the first and second island chains, where Beijing advocates saturation-attack doctrines involving successive waves of different missile types intended to overwhelm the defences available to regional allies. At the same time, the deployment of intermediate-range land-based systems such as Typhon during exercises in Japan has drawn a strong reaction from China and raised the profile of the regional strategic debate.

US Navy low-cost air defence against drones

Against this backdrop, the US Navy has repeatedly highlighted a structural challenge: the cost curve of air defence. Using expensive missiles to intercept cheap drones could become unsustainable during a prolonged conflict. One response being advanced by the Pentagon is to broaden the range of lower-cost options, combining hypervelocity ammunition, interceptors, interceptor drones and guided munitions launched from systems already available aboard ship. This approach received public attention when a June 2025 House Armed Services Committee hearing outlined accelerated work to assess and deploy new capabilities specifically intended to counter UAS on deployed vessels.

Among these trials, one of the most significant involved the Hypervelocity Projectiles (HVP) developed by BAE Systems. Reports stated that, in August 2024, during the USS Harry S. Truman (CVN-75) Composite Training Unit Exercise, the destroyer USS Jason Dunham conducted an HVP test as part of an assessment campaign intended to determine future courses of action for “low-cost” air and missile defence. Operationally, HVP is attractive because of its speed and its potential use from naval artillery systems already integrated into the fleet, expanding the available responses to aerial threats without expending higher-value interceptors.

HVP and the MDAC air-defence architecture

As noted previously, a full MDAC system battery will be equipped with eight guns, four high-precision MFPR multifunction radars, two MDBM multi-domain radars and at least 144 HVP rounds. Its modular design and integration with advanced radars will enable it to neutralise targets efficiently without relying on costly interceptors such as the PAC-2, PAC-3 or SM-6. This capability makes it an ideal architecture for strengthening the air defence of bases, strategic facilities and troop concentrations.

It is important to clarify that the test campaigns carried out in mid-2024 also involved other assets, including the destroyer USS The Sullivans, which assessed alternatives such as Longbow Hellfire, Anduril’s Roadrunner and Raytheon’s Coyote. In more straightforward terms for modern warfare, the message is clear: counter-drone defence cannot be solved by a single “silver bullet”, but instead requires a layered group of solutions-some cheaper and quicker to replenish-to maintain the pace of interception against mass attacks. In its assessment to Congress, the US Navy stated that these options had proved effective in shooting down drones and other aerial threats more cost-effectively than traditional solutions based solely on missiles.

Typhon deployment and Indo-Pacific deterrence

Set against this Indo-Pacific-centred technological race, the introduction of land-based systems such as Typhon-capable of using munitions including Tomahawk and SM-6-does more than add firepower. It also forces China to reconsider assumptions about freedom of manoeuvre within the first island chain. This explains the firmness of China’s diplomatic responses, which portray such deployments as threats to regional strategic security.

In this respect, the US effort is not simply about adding “more interceptors”. It is about continuing to build a framework in which rapid detection, immediate deployment and the proliferation of cost-effective defences can sustain attrition, prevent saturation and preserve the operational continuity of assets that could be used in a highly complex scenario such as the Pacific. It represents a shift in both tempo and logic: integrating sensors, effects and platforms so that defence is not only more powerful, but also less expensive to sustain over time.