Adv. zyxwvutsrqponmlkjihgfedcbaZYXWV SpaceRes. Vol. 23, No. 2, zyxwvutsrqponmlkjihg pp. 333-340, 1999 Q 1999 COSPAR. Published by Elsevier Science Ltd. All rights reserved Pergamon PII: SO273-1177(99)00054-X Printed in &eat Britain 0273-l 177199 $20.00 + 0.00 zyxwvutsrq THE COSAC EXPERIMENT ON THE LANDER OF THE ROSETTA MISSION H. Rosenbauer’, S.A. Fuselier2, A. Ghielmetti2, J.M. Greenberg3, F. Goesmann’, S. Ulamec4, G. Israel’, S. Livi’, J.A. MacDeimott6, T. Matsuo’, C.T. Pillinger’, F. Raulin’, R. Roll’, and W. Thiemann” ‘Max-Planck-lnstitutf: Aeronomie, M ax- Planck- Str. 2, O - 37191 Katlenburg- Lindau, Germany ‘Lockheed M artin Space Science Laboratory , 3251 Hanover Street, Palo Alto, CA 94304, USA 3Huygens Laboratory, Leiden University, NG2300 RA Leiden, The Netherlands ‘Deutsches zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA Zentrum zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA fiir Lt.@ - und Raumfahrt, DLR-MUX, D-51 147 Koln, Germany ‘Service d’Aeronomie du CNRS, F-91371 Verridres-le-Buisson, France 6Dept. of Chemistry, Lensfield Road, Cambridge CB2 IEW , U.K. ‘University Osaka, Dept. of Physics, Toyonaka, Osaka 560, Japan ‘Open University, Planetary Science Unit, W alton Hall, Milton Keynes MK7 6AA, U.K. ‘LISA, CNRS & Universites Paris 12 & 7, 61 Av. du General de Gaulle, F-94010 Cre’teil, France “Physikalische Chemie FB02, Universitat Bremen, Leobener Strasse, D-28334 Bremen, Germany ABSTRACT The COSAC experiment on the Lander of the ESA mission ROSETTA is aimed at the in situ investiga- tion of matter of a cometary nucleus (P/Wirtanen) with respect to its chemical and isotopic composition. Special emphasis is put on the identification of complex organic molecules including their chirality. The instrument, presently under development, will employ for analysis a multi-column gas-chromatograph and a high-resolution TOF mass spectrometer. These instruments can be controlled from ground and used either separately or in the GC/MS coupling mode. They are suited for analysis of the natural cometary atmosphere or pyrolytically generated gas from surface or near-surface samples. INTRODUCTION 01999 COSPAR. Published by Elsevier Science Ltd. The Scientific Scenario After several cometary fast flyby missions (e.g. GIOTTO, VEGA) which provided, among else, first images of a cometary nucleus and in situ measurements of the composition of gas and dust released from the surface, it is the goal of the ESA ROSETTA Mission to explore the nucleus of a comet in detail from close distance over an extended period of time, not only remotely from the Orbiter, but also by means of a Lander on the surface of the nucleus. The ROSETTA Mission Rosetta is an ESA comer-stone mission for cometary research including a Lander. An Ariane V is to launch a 2 ton (dry mass) spacecraft with appr. 240 kg scientific payload in early 2003. After two gravity- assist flybys at Earth and one at Mars, the spacecraft will be on an elliptic orbit with an aphelion of appr. 5.1 AU and a perihelion of appr. 1.1 AU which is close to the trajectory of the target comet PWirtanen. After flybys for scientific reasons at two asteroids (at present 140 Siwa and 4979 Otawara are the targets favoured most), the spacecraft will approach the comet in 2011 at a heliocentric distance of about 4.5 AU. After careful inspection of the nucleus by means of the on-board cameras and selection of a landing site, the landing manoeuvre is expected to take place in 2012 at a heliocentric distance of appr. 3 AU. 333