The X-37 's aerodynamic design was derived from the Space Shuttle , hence the X-37 has a similar lift-to-drag ratio , and a lower cross range at high altitudes and mach numbers than the Hypersonic Technology Vehicle . The X-37 's aerodynamic design was derived from the Space Shuttle , hence the X-37 has a similar lift-to-drag ratio , and a lower cross range at high altitudes and Mach numbers than DARPA 's Hypersonic Technology Vehicle .