Launcher Pre-Design: VENUS II - Trajectory optimisation with ASTOS

Abstract

This technical report gives an overview of the results of the trajectory analyses done with Astos for the 3- stage and the 4-stage launch vehicles studied in the framework of the VENUS II DLR-Astrium contract. Following the preliminary design and the CEF studies, additional analyses done at Astrium Bremen and Astrium Ottobrunn allow refining the mass budget of the stage and the engine performances for both concepts. Based on these results (status 5th April 2011), trajectory analyses and optimisations have been done with the help of Astos and Tosca for the reference 700 km polar orbit, for a 700 km sunsynchronous orbit and for the ISS orbit. Contrary to what the results of the CEF left to think, based on the more accurate mass estimations, the two configurations have quite difference performances. Indeed the 3-stage configuration has a maximum payload performance for the reference orbit around 2350 kg, whereas the 4-stage configuration can only put around 1850 kg in the reference orbit.