SP-1291 ESA Member States Austria Investigations Scientific The EXPRESS → MARS Belgium Czech Republic Denmark Finland France Germany Greece Ireland Italy Luxembourg Netherlands Norway Portugal Spain Sweden Switzerland United Kingdom → MARS EXPRESS The Scientific Investigations E uropean Space Agency Agency Space uropean An ESA Communications Production Copyright © 2009 European Space Agency SP-1291 June 2009 → MARS EXPRESS The Scientific Investigations Cover: An image taken by the High Resolution Stereo Camera (HRSC) on ESA’s Mars Express. See page viii for the full image. (ESA/DLR/FU Berlin/G. Neukum) An ESA Communications Production Publication Mars Express: The Scientific Investigations(ESA SP-1291, June 2009) Project Leader K. Fletcher Scientific Coordinator O. Witasse, Research & Scientific Support Dept., ESA Editing/Layout Contactivity bv, Leiden, the Netherlands Publisher ESA Communication Production Office ESTEC, PO Box 299, 2200 AG Noordwijk, the Netherlands Tel: +31 71 565 3408 Fax: +31 71 565 5433 www.esa.int ISBN-10 92-9221-975-8 ISBN-13 978-92-9221-975-8 ISSN 0379-6566 Copyright © 2009 European Space Agency ii Contents Foreword v Overview Mars Express: Summary of Scientific Results 1 A. Chicarro, O.G. Witasse & A.P. Rossi Scientific Instruments HRSC: High Resolution Stereo Camera 15 G. Neukum, R. Jaumann and the Co‑Investigator Team OMEGA: Observatoire pour la Minéralogie, l’Eau, 75 les Glaces et l’Activité J.‑P. Bibring, Y. Langevin, F. Altieri et al. MARSIS: Mars Advanced Radar for Subsurface 97 and Ionospheric Sounding J.J. Plaut, G. Picardi, T.W. Watters et al. PFS: Planetary Fourier Spectrometer 115 V. Formisano, F. Angrilli, G. Arnold et al. SPICAM: Spectroscopy for the Investigation of the 139 Characteristics of the Atmospheric of Mars J.-L. Bertaux, O. Korablev, D. Fonteyn et al. ASPERA-3: Analyser of Space Plasmas and Energetic Neutral Atoms 199 R. Lundin, S. Barabash and the ASPERA-3 team MaRS: Mars Express Radio Science Experiment 217 M. Pätzold, S. Tellmann, T. Andert et al. Operations and Archiving Mars Express Science Planning and Operations 249 R. Pischel & T. Zegers Spacecraft and Payload Data Handling 257 J. Zender, F. Delhaise, C. Arviset et al. Acronyms and Abbreviations 279 iii FOREWORD Mars Express: foreword Mars Express arrived at its destination in December 2003 to investigate most of the facets of the Red Planet – the interior, surface, atmosphere and ionosphere – in unprecedented detail. In addition to these global studies, the unifying theme of the mission is the search for water in its various states everywhere on the planet. The resulting water inventory (so far covering water vapour and water ice) has a great significance for the search for potential life forms, past or present, on the surface and below. The first ESA volume (SP-1240, Mars Express: The Scientific Payload), describing the scientific instruments, was published a few months after arrival. This companion volume focuses on the scientific results up to the end of the mission design lifetime (nominal mission and first extension), bearing witness to the tremendous success of Mars Express, scientifically and technically. The nominal science mission (January 2004 – November 2005) has already been extended twice (November 2005 – September 2007 and September 2007 – May 2009). Funding for a third extension (May 2009 – December 2012) is being requested. Following a summary of the scientific results so far presented in a thematic manner, the scientific investigations are explained in detail in this volume for each of the instruments. First, the instruments dealing primarily with the solid planet (subsurface and surface): the High Resolution Stereo Camera (HRSC), the OMEGA infrared mineralogical mapper, and the MARSIS subsurface sounding radar. Second, the instruments addressing the gaseous planet (atmosphere and ionosphere): the Planetary Fourier Spectrometer (PFS), the SPICAM UV and IR spectrometer, and the ASPERA Energetic Neutral Atom Analyser. Finally, the MaRS radio science experiment, providing insights into all areas, including interior gravity anomalies, surface roughness, atmospheric and ionospheric structure, and solar corona. Two further chapters, on science planning and operations, and data archiving complete the volume. Mars Express is the first European mission to another planet, following ESA missions to other Solar System bodies (Giotto to Comet Halley and Huygens to Saturn’s moon Titan) by the Science Programme. Mars Express has opened the way to the exploration of Mars in Europe, soon to be followed by missions of ESA’s Aurora Exploration Programme. ExoMars will focus on detailed geochemical analysis of the martian surface with an ambitious rover, and Mars-NEXT will establish a network of three or four surface stations complemented by an orbiter to determine the deep internal structure of the planet and the global circulation of the atmospheric, and to analyse the rocks and soil at each landing site. Mars-NEXT will be an important technological milestone in preparation for the international Mars Sample Return mission. Mars Express has positioned European scientists at the forefront of Mars research in all fields, giving Europe a significant presence at international planetary sciences meetings. In spite of numerous US missions to Mars, Mars Express has provided exciting new and fully complementary scientific results. It has taken its rightful place between NASA’s Mars Global Surveyor and the Mars Exploration Rovers, and the Mars Odyssey and Mars Reconnaissance Orbiter missions. Mars Express has given ESA unprecedented visibility among the general public worldwide, unmatched until the later landing of Huygens on Titan. Through its data archive, its data are continuously being made available to the scientific community in all fields of research. Biweekly web releases are reaching a vast portion of the general public on all continents. From a technical point of view, the legacy of Mars Express is highly significant, showing that first-class planetary missions can be built in record time with limited resources. This made Venus Express possible by using the same spacecraft design and more than half of the Mars Express instruments. From a scientific point of view, in addition to the outstanding results in all areas of Mars science, the legacy of the mission will be measured by the global imaging of its surface at high resolution, largely improving on the 1970s Viking coverage. Agustin F. Chicarro Mars Express Project Scientist ESTEC, September 2008 vii SP-1291 First high-resolution colour-coded Digital Terrain Model (DTM) mosaic with superimposed HRSC ortho mosaic of the central part of Valles Marineris. The stereo information from 20 HRSC individual orbit swaths has been used to generate a DTM mosaic with a ground resolution of 100 m per pixel. The information from the high-resolution panchromatic nadir channel of the HRSC has been used to create an ortho-image mosaic with a ground resolution of 25 m per pixel covering an area of approximately 630 000 km2. Both sets of processed data have been combined to create this sharpened colour-coded DTM view. viii Mars Express First near-true colour oblique view of the central part of Valles Marineris. The stereo information from 20 HRSC individual orbit swaths has been used to generate a DTM mosaic with a ground resolution of 100 m per pixel together with the colour information of 12 HRSC orbit swaths to generate this near-true colour ortho-image mosaic covering an area of approximately 630 000 km2. In order to improve the spatial resolution, the HRSC colour channels and the high- resolution nadir channel have been combined (Hue-Intensity-Saturation Transformation) and then recast into a sharp, improved colour image. This colour image and the DTM data combined have been used to generate the particular bird’s eye view of Valles Marineris at an angle of 45° to the surface at four times vertical exaggeration. ix OVERVIEW 1 Mars Express: Summary of Scientific Results A.F. Chicarro, O.G. Witasse & A. Pio Rossi Solar System Missions Division, Research & Scientific Support Department, ESA/ESTEC, PO Box 299, 2200 AG Noordwijk, the Netherlands Email: [email protected] Mars Express is the first European mission to another planet. It has opened the way to further European exploration of Mars with the ExoMars rover and, one day, with a network of surface stations in preparation for the international Mars Sample Return mission. The Mars Express spacecraft has been orbiting the Red Planet for more than five years, during which time it has investigated many scientific aspects of Mars in unprecedented detail, which are summarised in this chapter. Mars Express has revolutionised our understanding of the planet’s geological evolution, allowing us to build a comprehensive and multidisciplinary view of Mars, including the surface geology and mineralogy, the subsurface structure, the state of the interior, the climate’s evolution, the atmospheric dynamics, composition and escape, the aeronomy and the ionospheric structure. Major advances have been made through discoveries such as the very recent (in geological timescales) occurrence of volcanic and glacial processes, the presence of water ice below the surface and the fine structure of the polar caps. The various types of ice in the polar regions have been mapped, and the history of water abundance on the surface of Mars has been determined in view of the alteration minerals formed at different epochs. The mission has revealed the unequivocal presence of methane in the atmosphere, the existence of nightglow, mid-latitude auroras above crustal magnetic fields in the southern highlands and very high-altitude CO2 clouds, as well as the solar wind scavenging of the upper atmosphere down to 270 km altitude and the current rate of atmospheric escape. Detailed studies have been made of the crustal gravity anomalies (and thus the properties of the interior), the surface roughness and the fine structure of the ionosphere. Indeed, the presence of methane, independently confirmed by ground measurements, suggests that either volcanism or biological processes are currently active on Mars.