Ukrainian servicemen walk past a Patriot air defence system in an undisclosed location, on Aug. 4, 2024. Sergei Supinsky/AFP via Getty ImagesUkraine has tested a new surface-to-air missile intended to offer a cheaper alternative to the interceptor missiles used in the U.S.-made Patriot air-defense system.The Patriot air-defense system is designed to shoot down tactical ballistic missiles, cruise missiles, and aircraft and has been heavily relied on by Ukraine for the bulk of the war.