Encyclopedia entry XCOR USA Original archive entry. The text, images and links below are kept as they were written. XCOR Aerospace RelatedCountryUSAEnginesRotary Rocket, XR2P1, XR3A2, XR3B4, XR3M9, XR4A3, XR4K14, XR4K5, XR5M12, XR5M15SpacecraftXerus