TRAVELLING AT SUPERSONIC SPEED
SUPERSONIC SPEED IS A RATE OF TRAVEL OF AN OBJECT THAT EXCEEDS THE SPEED OF SOUND. FOR OBJECTS TRAVELING IN DRY AIR OF A TEMPERATURE OF 20 °C, THIS SPEED IS APPROXIMATELY 1,235 KM/H.
SPEEDS GREATER THAN FIVE TIMES THE SPEED OF SOUND ARE OFTEN REFERRED TO AS HYPERSONIC.
FLIGHT DURING WHICH ONLY SOME PARTS OF THE AIR AROUND AN OBJECT, SUCH AS THE ENDS OF ROTOR BLADES, REACH SUPERSONIC SPEEDS ARE CALLED TRANSONIC.
Most modern fighter aircraft are supersonic, but there have been supersonic passenger aircraft, namely Concorde and the Tupolev Tu-144. Both these passenger aircraft and some modern fighters are also capable of supercruise, a condition of sustained supersonic flight without the use of an afterburner. Due to its ability to supercruise for several hours and the relatively high frequency of flight over several decades, Concorde spent more time flying supersonically than all other aircraft combined by a considerable margin. it profitably flew these routes in less than half the time of other airliners. With only 20 aircraft built, the development of Concorde was a substantial economic loss; Since Concorde's final retirement flight on November 26, 2003 after a crash, there are no supersonic passenger aircraft left in service.
Most spacecraft, most notably the Space Shuttle are supersonic at least during portions of their reentry, though the effects on the spacecraft are reduced by low air densities. During ascent, launch vehicles generally avoid going supersonic below 30 km (~98,400 feet) to reduce air drag.