The US air force will test an experimental aircraft on Tuesday designed to fly at six times the speed of sound, or about 4,600mph.
The X-51A Waverider will be dropped from a B-52 bomber at around 50,000ft over the Pacific Ocean before attempting to achieve speeds that would see it fly from New York to Los Angeles in 46 minutes.
It is the third test of the hypersonic aircraft in the last two years. The earlier incarnations failed to fly for the 300 seconds that engineers hope the X-51A will be able to sustain, leading to tweaks to the craft's engine ahead of Tuesday's launch.
The Los Angeles Times reported that the X-51A, which is unmanned, is expected to reach Mach 6 when it takes flight off the Southern California coast near Point Mugu. The aim of flying for five minutes is longer than the aircraft's personal best, which came in 2010 when it flew for more than three minutes.
Robert A Mercier, from the high speed systems division at the Air Force Research Laboratory in Ohio told the LA Times:
Attaining sustained hypersonic flight is like going from propeller-driven aircraft to jet aircraft. [...] Since the Wright brothers, we have examined how to make aircraft better and faster. Hypersonic flight is one of those areas that is a potential frontier for aeronautics. I believe we're standing in the door waiting to go into that arena.In the most recent test, in 2011, the X-51 fell for about four seconds before its booster rocket ignited, but the aircraft failed to separate from the rocket and plunged into the ocean. Although the potential for the X-51 to ferry passengers around the world at hitherto unheard-of speeds will catch the eye, the most likely potential use for the craft is as a missile capable of hitting targets thousands of miles away in an extremely short space of time.
The hypersonic craft, which weighs around 4,000lb and in present form is capable of travelling over 400 miles, has been built by Boeing in collaboration with the US air force. After it is dropped from the B-52 it is set to climb to around 70,000ft during the 300-second flight, before breaking up over the Pacific Ocean.