The fastest-ever manned aeroplane made its record-setting flight 47 years ago. In the early days of the Space Race, the X-15 was designed to test the limits of aeronautical engineering at the edge of space. Built like a short-winged fighter jet, the X-15 packed a rocket under its hood. To fly, it would hitch a ride on a massive B-52 up to 13,700 metres (45,000 feet). Dropped from the bomber, the X-15 lit its liquid propellant rocket capable of 500,000 horsepower. The X-15 only carried enough fuel for 83 seconds of powered flight – but it was enough to rocket its pilots into the record books.