June 12, 2009 8:54 AM PDT
An X-15 takes off from its B-52 mothership, in this photo from 1959. These airborne launches took place at about 45,000 feet with the planes moving at 500 miles per hour or better. The X-15 typically was propelled by its rocket engine for about 1 to 2 minutes, then flew for 8 to 12 minutes without power before--even with its stubby wings--coming to Earth in a 200-mph glide landing.
The inaugural flight in June 1959 was a completely unpowered glide flight intended to check out the handling of the X-15. The second flight, which took place in September of that year, was the first in which the X-15 was powered.
Photo by NASA
Caption by Jonathan Skillings
