Two-stage-to-orbit spaceplane concept with growth potential

A two-stage-to-orbit (TSTO) spaceplane concept developed in 1993 is revisit ed, and new information is provided to assist in the development of the nex t-generation space transportation vehicles. The design philosophy, TSTO spa ceplane concept, and the design method are briefly described. A trade study between cold and hot structures leads to the choice of cold structures wit h external thermal protection systems. The optimal Mach number for staging the second stage of the TSTO spaceplane (with airbreathing propulsion on th e first stage) is 10, based on life-cycle cost analysis. Mass properties of four TSTO spaceplanes with a turbo/ram/scramjet propulsion system on the f irst stage are presented, and the specification and performance of one of t hese spaceplanes are discussed. Two of these spaceplanes have builtin growt h potential, and one of these is proposed as a prototype/experimental TSTO spaceplane to address the near-term access to space needs. The internal rat e of return on investment is the highest for the proposed TSTO spaceplane, vis-A-vis a single-stage-to-orbit rocket vehicle and a TSTO spaceplane with out builtin growth. Additional growth potentials for the proposed spaceplan e are suggested. This spaceplane-can substantially decrease access-to-space cost and risk and increase safety and reliability in the near term. It can be a serious candidate for the next-generation space transportation system .