Hypersonic weapon

A hypersonic weapon is a weapon capable of travelling at hypersonic speed, defined as between 5 and 25 times the speed of sound or about 1 to 5 miles per second (1.6 to 8.0 km/s).^[1]

Below such speeds, weapons would be characterized as subsonic or supersonic, while above such speeds, the molecules of the atmosphere disassociate into a plasma which makes control and communication difficult.

There are multiple types of hypersonic weapon:

1. Hypersonic glide vehicle (HGV): missile warheads which maneuver and glide through the atmosphere at high speeds after an initial ballistic launch phase^[2][1]
2. Hypersonic cruise missile: cruise missiles which use air-breathing engines such as scramjets to reach high speeds^[2][1]
3. Hypersonic aircraft using air-breathing engines such as scramjets to reach high speeds^[1]
4. Guns which fire cannon-launched guided projectiles. These may be developments of traditional artillery or novel technologies such as railguns.^[1]

Other types of weapons, such as traditional ballistic missiles, may achieve hypersonic speeds but are not typically classified as hypersonic weapons due to lacking the use of aerodynamic lift to allow their reentry vehicles to maneuver under guided flight within the atmosphere.^[3][4]