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SpaceRef - Exploration and Missions - Human Missions - Atmospheric Tests and Experimental Aircraft - X-Planes
X-Planes Project Overview - The "X" designation, originally "XS" for eXperimental Supersonic, applied to a family of experimental aircraft not intended for production beyond a limited number built solely for flight research. This page documents the history of X-plane research at NASA and its predecessor, NACA. from the X-1 to the X-33, X-34, X-37, and X-38.
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