The sign accompanying the X-15. It reads
North American X-15A-2
The X-15, designed to provide data on materials and human factors of
high-speed, high-altitude flight, made the first manned probes into the lower
edges of space. It was built for speeds up to 4,000 mph and altitudes of 50
miles, but these goals were exceeded on numerous occasions. Several X-15
pilots earned "astronaut" rating by attaining altitudes above 50 miles. The
X-15 program contributed significantly to the Mercury, Gemini, and Apollo
The X-15 was carried aloft by a B-52 and was released at
about 45,000 feet and 500 mph. Its rocket engine then fired for the first 80
to 120 seconds; the remainder of the 10 to 11 minute flight was powerless and
ended with a 200 mph glide landing on a dry lake bed.
The first powered X-15 flight was made on September 17, 1959, and 199 flights
were made between 1959 and 1968 by the three X-15s which were built. The No. 1 X-15 is at the National Air and Space Museum, Washington,
D.C., and the No. 3 X-15 was destroyed in a crash. The No. 2 aircraft was
retired to the USAF Museum in October 1969.
||22 ft. 5 in.
||52 ft. 5 in.
||56,132 lbs (at launch with ram-jet test engines)
||Reaction Motors YLR-99 rocket
of over of 50,000 lbs. thrust [heroicrelics: all other sources I've seen
refer to the engine as the "XLR-99"]
||4,520 mph/3,927 knots (unofficial record)
||More than 250 statute miles/217 nautical miles (flight
||354,000 ft (unofficial record)