And yes, both the Air Force and NASA say it went into space.
UNVEILING THE X-15
Model: North American X-15, a manned, hypersonic research aircraft. Length: 50 it. Height: 13 ft.
Wing area: 200 sq. ft. in a 25° sweep-back. Weight at launching: 31,275 lbs. Cargo: Pilot plus 1,300 lbs. of instruments. Fabrication: Inconel-X, titanium and stainless steel to withstand temperatures in excess of 1,000°F.