RE-IGNITABLE EPS UPPER STAGE PROVIDING FULL VERSATILITY FOR ARIANE 5

摘要

On the 16th of February 2011, close to three years after the first-ever launch of the ATV (Automated TransferVehicle), dubbed Jules Verne, into LEO (Low Earth Orbit), ATV-2 Johannes Kepler was launched with the A5ES(ARIANE 5 Evolution Stockables) L544 launcher in order to serve once again the ISS (International Space Station)by an ATV.This paper presents the evaluation of the ATV-2 Johannes Kepler flight mission results and compares the data withATV-1 Jules Verne post flight analysis. Further the A5ES ATV launcher behavior is compared to a standard typeGTO mission with an ARIANE 5 GS (Generique Stockables - Generic Configuration with Upper Stage propelled byStorable Propellants) launch vehicle. The chosen mission is the A5GS L526 launch as here once again a re-ignitiondemonstration of 7 seconds of EPS (Etage à Propergols Stockables) upper stage AESTUS engine was performedafter the A5GS launcher commercial mission. Finally the comparison includes not only the flight data from three A5missions but also the flight performance prediction for the future A5ES Galileo mission is considered. The A5ESGalileo mission will be performed into a MEO (Medium Earth Orbit) and will be in fact a mixture of a GTO mission(e.g. taking into account the initial propellant loading) and an ATV mission (e.g. P/L separation is taking place afterthe first re-ignition boost phase).The focus within the comparison is put on the FPS (Functional Propulsion System) behavior of the ARIANE 5 upperstage EPS including also the Engine re-ignition behavior in flight under different thermal conditions by taking intoaccount measurement data from qualification and acceptance hot firing tests on ground and of the VEB (VehicleEquipment Bay) stage with a special focus on the SCA (Système de Contr?le d'Attitude - Attitude Control System).The comparison is split into the different launch vehicles life phases starting with the ground phase on ZL (Zone deLancement - Launch Pad) and ending with De-orbiting phase.No major flight anomaly occurred up to now w.r.t. EPS re-ignition boost phases and ballistic flight phases so that noblocking point exists w.r.t. the performance of the remaining ATV missions ATV-3 to ATV-5 in the next years andthe functional feasibility of the A5ES Galileo mission for the deployment of the Galileo satellites by A5 is shown.