ELV: Pressure-fed LO_x/LH_2 upper stage

摘要

Cnes is leading extensive studies for the future generation of ELVs. The trend is today to research easy to use, robust and reliable solutions for the propulsion of future expendable launch vehicles but also with a high level of performances associated to as low as possible recurring cost of the launch vehicle. Among the different configurations (i.e. "linear", linear with SRBs, tri stages, parallel with cross feeding) conventional two stage architecture seems the one of the best to reach these goals. In the two stage configuration, there is competition between SRB (500ton of propellant), LO_x/LH_2 (350ton of propellant) or even LO_x/methane, but always the second stage is cryotechnic (LH_2/LO_x), different technological solutions are possible.rnA way could be an extensive use of composite materials both for the structures, the tanks and the engines with use, as much as possible of automatic processes. In near future breakthrough or improvement of the fiber strength may increase the interest of such technologies.rnThe aim of this paper is to present the technical choices for 40ton of propellant second stage leading to cost effective configuration.