When Russia fires a ballistic missile at Ukraine, air-defence systems have only minutes – sometimes seconds – to detect and intercept the deadly threat. The lack of time has left Kyiv and other cities increasingly exposed to devastating attacks by the missiles that come down so fast and so steeply that Ukraine says only the US-made Patriot defence system can stop them. But Ukraine says it has too few batteries and interceptors to protect itself. Unlike cruise missiles, which behave like...