On-Demand Reusable Space Launch Systems That Use In-Flight Oxidizer Collection 931451
This paper describes air breathing reusable space launch vehicle concepts intended to provide very rapid response launch of 10,000 lb polar orbit payloads (or approximately 20,000 lbs Eastern). The vehicles are two-stage, with the first stage employing turboramjet propulsion and the second stage using rockets. Liquid oxygen (LOX) for the second stage is collected during first stage ascent using technologies from the original Aerospaceplane work along with recent improvements. No LOX is carried at takeoff, thus eliminating the need for LOX ground servicing facilities.
A dual fuel approach, liquid hydrogen and ambient storable hydrocarbon fuel (LH2 and JP), uses JP fuel for first stage acceleration and second stage rocket ascent. LH2 in the amount just sufficient to condense and collect second stage LOX, is the only cryogenic fluid that is loaded on the vehicle at takeoff. Another concept, which eliminates all cryogenics at takeoff, uses the heat sink of conventional JP fuel and water coolant to drive a lightweight adaptation of the commercial LOX production process.
Both of the concepts are believed to permit true launch-on-demand capability since ground operations would be aircraft-like, using conventional airbase facilities and services.