Orbital Space Plane, Past, Present, and Future

Abstract

This paper addresses the future of flight test for the American space program. The key emphasis is development of an orbital space plane (OSP). The discussion includes high-level mission analysis and includes those configurations that are most advantageous for accomplishing the space plane mission. Examination of operational requirements; launch, reentry, and orbital phases of the mission; and the feasibility of single-stage-to-orbit (SSTO) follows. The paper discusses reusable and expendable launch vehicle issues, compares previous space plane concepts and key performance elements, and presents data indicating vertical-launch-horizontal-landing as the most economical concept for achieving space plane objectives. While launch and reentry mission phases can be accomplished with a wingless vehicle; the higher lift-to-drag ratio of a delta-winged vehicle offers a significant increase in operations flexibility. This makes a case for the X-37 as a platform for integrating technologies and for redeveloping the operational experience required for deploying an OSP. Methods for testing prototype OSP configurations are discussed. The examination suggests movement from an initial test-and-development vehicle with no humans on board to an operational space plane with full cockpit and a wide variety of pilot displays and capabilities. Nomenclature