Explainer

The US Is Behind on Deploying Hypersonic Weapons. Why It Matters

People's Liberation Army YJ-20 hypersonic aeroballistic missiles at Tiananmen Square during a military parade held in Beijing on Sept. 3.Photographer: Qilai Shen/Bloomberg

Hypersonic weapons are so fast, their speed can change the surrounding air molecules. They can carry a nuclear warhead, fly low and be hard to detect. Because of their potential to transform modern warfare, these weapons have become a key front in the intensifying race for military dominance between the US on one side and Russia and China on the other.

The US’s two chief rivals already deploy hypersonic projectiles. China’s military parade in September showed off a hypersonic “carrier killer” ballistic missile built to attack high-value naval targets. Ukraine claimed that Russia used a hypersonic missile to attack Kiev in early 2024.