06-07-2021, 08:07 PM
(This post was last modified: 06-07-2021, 08:11 PM by Tim Randal Walker.)
Mach (pronounced "mock" in American English and "mack" in British English, I believe) number is used to describe the speed of a supersonic aircraft. Mach 1 is the speed of sound, Mach 2 is twice the speed of sound, and so on. Hypersonic is the term applied to Mach 5 and above.
Other than astronauts (who were basically riding ballistic missiles) the fastest speed attained by a human was Mach 6.72 in the X-15 rocket plane. The fastest operational aircraft was the SR-71 spy plane, the fastest acknowledged speed being Mach 3.2. It has been rumored that there may be a successor spy plane reaching perhaps Mach 6, possibly a drone-I cannot confirm.
Governments know when a spy satellite will be overhead, so they may periodically attempt to hide their activities. But that may not work if a super fast spy plane makes an unannouced visit.
Other than astronauts (who were basically riding ballistic missiles) the fastest speed attained by a human was Mach 6.72 in the X-15 rocket plane. The fastest operational aircraft was the SR-71 spy plane, the fastest acknowledged speed being Mach 3.2. It has been rumored that there may be a successor spy plane reaching perhaps Mach 6, possibly a drone-I cannot confirm.
Governments know when a spy satellite will be overhead, so they may periodically attempt to hide their activities. But that may not work if a super fast spy plane makes an unannouced visit.