What is the Difference Between Supersonic and Hypersonic?
Simply put, hypersonic is considered to be above Mach 5 (five times the speed of sound), while supersonic is merely above Mach 1. The difference is one of degree, relating to certain dynamics of the airflow, but the supersonic/hypersonic distinction also has relevance to the defense world of the near future, in which aerospace companies must compete to give the armies of their home countries the fastest possible bombers and fighter planes. Methods of propulsion also differ greatly between the supersonic and hypersonic regimes, with air-breathing, or ramjet, designs more popular for increased speeds. Hypersonic is one of three rough classifications for airflow regimes – subsonic (less than Mach 0.8), transonic (Mach 0.8 – 1.2), supersonic (Mach 1.2 – 5.0), and finally hypersonic (Mach 5.0+). By comparison, a Space Shuttle in orbit travels at about Mach 23. The fastest conventional planes, such as the SR-71 Blackbird, reach flight speeds of about Mach 3.2. Scramjets, of which there has b
