Launch Vehicle Concepts Research Articles

Launch vehicle evolution - from multistage expendables to single-stage reusables

The paper provides a survey about the technical development trends and alternatives in the launch vehicle area. The traditional solution is the multistage expendable launch vehicle. The American STS with the reusable winged Shuttle is the first step towards a reusable system. While the launch cost of an expendable system comprises about 70% hardware cost, the STS (Shuttle) has reduced the hardware cost per flight to some 50%. A fully reusable vehicle would come down to less than 30%. The technical development trends as engine performance, stage mass ratio, vehicle payload ratio, etc. are discussed and the requirements for fully reusable two-stage and single-stage vehicles shown. For each launch vehicle concept examples are presented which have been conceived in the past 20 years. It is shown how the trend to fully reusable systems will allow to reduce the launch cost. As final and most cost-effective solution the single-stage winged vehicle will probably evolve for manned space transportation and small payloads, while for heavy cargo transportation the unmanned single-stage ballistic vehicle seems to be the most advantageous concept.

The transcost-model for launch vehicle cost estimation and its application to future systems analysis

The first part of the paper describes the structure of the analytical cost estimation model (1982 edition) for launch vehicle development, fabrication and launch operations cost. Especially the new approach for a cost assessment of operations cost including refurbishment (in case of reusable vehicles), direct and indirect operations is presented for discussion and subsequent improvements by introduction of more reference values. The model uses the Man-Year (MY) as cost unit which is independent from inflation and currency exchange rate changes. The second part of the paper deals with its application to future systems analysis and cost comparison with the example of a potential future European launcher (Post-Ariane-4) with 15 tons LEO payload capability: ten different two-stage launch vehicle concepts (expendable, semi-reusable and fully reusable) with storable and cryogenic propellants are analysed with respect to development cost and cost per launch. The key problem for a future European launch vehicle is the optimum solution between the (limited) development effort and the desired minimum launch cost. More advanced (partially) reusable systems could provide an essential reduction in cost per launch, require, however, a higher development effort. In such a case an analytical cost model based on realistic reference data can provide important data for the vehicle concept selection process.

Aerodynamics of a Turbojet-Boosted Launch Vehicle Concept

Results from analytical and experimental studies of the aerodynamic characteristics of a turbojet-boosted launch vehicle are presented. The success of this launch vehicle concept depends upon several novel applications of aerodynamic technology, particularly in the area of takeoff lift and minimum transonic drag requirements. The take-off mode stresses leading edge vortex lift generated in parallel by a complex arrangement of low aspect ratio booster and orbiter wings. Wind-tunnel tests on a representative model showed that this low-speed lift is sensitive to geometric arrangements of the booster-orbiter combination and is not predictable by standard analytic techniques. Transonic drag was also experimentally observed to be very sensitive to booster location; however, these drag levels were accurately predicted by standard farfield wave drag theory.

Solar power satellite transportation

Preliminary studies and concepts are discussed relative to the feasibility and economics of developing the capability to transport a network of operational 10-GWe solar power satellites into geosynchronous orbit by A.D. 2025. The satellite is briefly described, and its space transportation options are presented. Launch vehicle requirements and concepts are discussed in relationship to the transportation task.

Evaluation of multimission launch vehicle concepts.

The use of future launch vehicles for a multitude of mission applications appears to he a necessity. The specific applications for these future systems are uncertain at this time. The launch rates for present and projected future missions are relatively low. These low launch rates and the uncertainties in performance and operational modes focus attention on launch vehicles that have the potential of performing a range of missions. An evaluation and comparison is sho\vn for multimission and single-mission concepts capable of performing three typical future missions. This paper uses 13 evaluation criteria to measure the effectiveness of the several launch concepts. The results of a consensus to establish the relative value of the criteria are discussed. The flexibility of the multimission vehicles is shown to be achievable with only a small penalty in weight, although a superiority in cost is maintained.