The leaders of Australia, the United Kingdom, and the United States – dubbed AUKUS last fall – held a check in last week, reaffirming their commitment to a “free and open Indo-Pacific” as a result of China’s growing regional military ambitions and Russia’s worsening war in Ukraine. How were they going to do this? The three allies announced they would broaden the original intent of the AUKUS alliance by developing hypersonic weapons.

What is AUKUS?

Last September, Australia, the United Kingdom, and the United States – known as AUKUS – revealed that the United States and the United Kingdom formed the alliance to help Australia build nuclear-powered submarines. Until this time, the United Kingdom was the only foreign country with which the United States shared its highly coveted and top-secret nuclear submarine technology, highlighting the significance of the alliance and sharing this technology with Australia. The creation of the trilateral alliance served a national interest for each participating country, reflecting, as the Economist summarizes, “Australia’s fear of China’s growing power, America’s willingness to break old taboos to counter it, and Britain’s eagerness to bolster its role in Asia.”

What are Hypersonic Missiles?

Typically, hypersonic missiles are defined as “fast, low-flying, and highly maneuverable weapons designed to be too quick and agile for traditional missile defense systems” to detect before the weapon hits its target. These missiles travel five times faster than the speed of sound, flying approximately one mile per second. What makes hypersonic missiles – including each of the three types, hypersonic aeroballistic missile, the hypersonic glide vehicle, or the hypersonic cruise missile – so hard to detect is that, unlike ballistic missiles, they don’t follow a pre-determined, arched trajectory and can maneuver on the way to their target. These missiles are so fast that they cannot be intercepted by any current missile defense system.

AUKUS and Hypersonic Missiles

The United States, China, and Russia have the most advanced hypersonic missile capabilities in the world. Other countries, including several U.S. allies and an adversary, are working on developing the technology. North Korea reportedly launched tow hypersonic missile tests in January, though there is speculation whether the tests were successful.

For years, the United States has collaborated with one ally in particular, Australia, to conduct hypersonic missile research. In fact, the United States and Australia already have an existing joint program to develop the weapons. The United Kingdom, with whom the United States and Australia will be developing hypersonic missiles, is further behind. According to the British government, there were no plans in the works for the United Kingdom to develop its own missiles; however, the AUKUS agreement would help assess whether the need to develop such missiles would be necessary in the future.

As China and Russia increase their hypersonic missiles, the U.S. has shown interest in further developing its own capabilities. Knowing that, it’s easy to see why the United States wants to work with some of its closest partners. With the advent of AUKUS’s quest beyond nuclear submarines, the United States and its Australian and British allies can effectively confront both China and Russia in this arena.

A Sputnik Moment

The AUKUS expansion comes in the face of China’s increasingly aggressive military posture in the Indo-Pacific region. Last fall, China stunned the U.S. military with two hypersonic missile tests. While Beijing called it a played down the test by calling it routine, U.S. officials were alarmed at how more advanced China’s capabilities are when compared to those of the United States. General Mark Milley, the Chairman of the Joint Chiefs of Staff, noted that the test was “very close to a Sputnik moment.” The tacit contest to develop hypersonic missiles features prominently in the U.S.-China relationship, leading some observers to fear that a race to acquire the most sophisticated and advanced hypersonic missile capabilities may be afoot.

Hypersonic Missile Use Claimed in Ukraine

The AUKUS development of hypersonic missile capabilities is not only directed at China’s regional aggression. Russia’s recent invasion of Ukraine has the United States and its allies on alert as well. In mid-March, Russia claimed it used a hypersonic missile in western Ukraine, becoming the first country to use the missiles in combat and caused great alarm across the West. At a time when the United States and its European allies are at a crossroads in its fight against Russia in Ukraine, the use of hypersonic missiles adds an entirely new layer into the war and further reiterates foreign policy analysts’ concerns on an arms race between the great powers.

A Hypersonic Alliance

As the world’s leading great powers – the United States, an increasingly aggressive China, and a revanchist Russia – potentially set off an arms race to acquire hypersonic missile, the United States is ramping up its own capabilities. As part of the great power rivalries that are now central to U.S. foreign policy, the United States is turning to two of its closest allies.

What makes the AUKUS remarkable is not just the formation of the alliance, but the willingness to share sensitive and, at times, highly secretive technology. This was true in September when the United States and United Kingdom agreed to share nuclear submarine technology with Australia within the AUKUS framework. The same can also be said for the alliance’s expansion to hypersonic missiles. The coordination and collaboration in other areas beyond nuclear submarine technology – including the development of hypersonic missile capabilities – may also allow the United States to expand to other allies and partners that share common foreign policy challenges.