The North American X-15 was the first winged vehicle to take a man into space and to speeds great than 6 times the speed of sound. The X-15 rocket research airplane was designed to conduct research experiments during actual flight conditions beyond the Earth's atmosphere and to obtain knowledge of aerodynamic heating, re-entry conditions, acceleration and deceleration forces, and reactions of man to weightlessness. It exceeded its design specifications of 4,000 miles per hour and altitudes up to 50 miles.