IAC-03-Q.4.04 1 VISION BASED NAVIGATION FOR PLANETARY EXPLORATION OPPORTUNITY FOR AURORA B.Polle, B.Frapard, T.Voirin EADS Astrium 31, avenue des Cosmonautes, 31402 Toulouse Cedex 4, France bernard.polle@astrium.eads.net J. Gil-Fernández, E. Milic, M. Graziano, R. Panzeca GMV S.A., c/ Isaac Newton 11, 28760 Tres Cantos, Madrid, Spain jesusgil@gmv.es J. Rebordão, B. Correia, M. Proença, J. Dinis, P. Motrena, P. Duarte INETI, Estrada do Paço do Lumiar, 1649-038 Lisboa, Portugal ABSTRACT Much interest has been given in recent years to vision based navigation for planetary mission. A dedicated experiment has been conducted by NASA on Deep Space One, further experiments are planned on the Mars Reconnaissance Orbiter spacecraft. Recently, the preparation of the European framework for a manned exploration of Mars, the so-called AURORA missions has set the challenge. This paper presents the progress in this frame, results of the ESA Technological Research Program “Autonomous Navigation for Interplanetary Missions” * . In a first part, navigation requirements of exploration missions are addressed. Navigation needs depends on phases, such as cruise, approach or rendezvous, and also on the nature of the target, either small or large bodies. Parametric performances for various classes of cruise and encounters, with large and small bodies, are presented and compared to mission requirements. Both impulsive and continuous propulsion are considered. Vision based navigation appears as a natural supporting technology for continuous propulsion systems. A preliminary camera design is presented. Major challenges in detection of faint objects, imagery of extended bodies with or without atmosphere, with low Sun-Object- Target angles are introduced and discussed. The first tests on images acquired on ground telescopes, combined with simulation of the navigation prototype demonstrate the maturity of the concept, preparing flight demonstration of this full concept planned in the frame of the ESA SMART-1 project in 2004. * ESTEC contract #15292/01/NL/EC INTRODUCTION The objective of this study is to take a major step towards a European capability for autonomous onboard navigation. The study involves design, prototype implementation and test of the developed autonomous onboard navigation system (ObNav) covering all the phases of the mission: cruise, low thrust deep space manoeuvre, planetary or small bodies (asteroid, comet or planet) encounters. The achieved navigation accuracy is generally competitive with ground based radiometric navigation and in some cases much more accurate. AN AURORA PERSPECTIVE In the frame of the AURORA missions, optical navigation is now a valuable alternative providing autonomy and accuracy for cruise navigation but also for aerocapture and rendez-vous. Low thrust cruise navigation is certainly the domain where optical navigation interest is more obvious allowing to recover autonomy in this phase where introduction of new propulsion technology actually decrease autonomy when using a conventional ground based radiometric navigation system. Accurate rendez-vous and encounter is also a potential application of vision based navigation, as has been demonstrated on DS1. Application to aerocapture, aerobreaking can also be considered as a potential application, although achievable accuracy in presence of planetary atmosphere has still to be demonstrated. This will be one of the main objectives of the SMART-1 navigation experiment planned in this study. Vision based navigation can also be applied to relative navigation in a Martian orbit rendez-vous with a passive target. Although this type of application is not within the scope of this study, many techniques developed are fully