Athena Coustenis (Αθηνά Κουστένη) is an Astrophysicist specialising in Planetology, Director of Research Exceptional Class with the National Centre for Scientific Research (CNRS) of France, working at theParis Observatory in Meudon.
View from a Titan lake shore: collage © Dimitris Sivyllis 



Athena Coustenis
Director of Research Exceptional Class CNRS

Paris-Meudon Observatory, France

Athena Coustenis is an Astrophysicist, Director of Research Exceptional Class with the National Centre for Scientific Research (CNRS) of France, working at Paris Observatory in Meudon. Her specialty is Planetology (exploration and study of the Solar System from ground-based and space observations). Her research is devoted to the investigation of planetary atmospheres and surfaces, with emphasis on the outer solar system bodies, in particular icy moons like Titan and Enceladus, Saturn’s satellites, and Jupiter’s Ganymede and Europa, objects with high astrobiological potential. She also works on the characterisation of exoplanetary atmospheres. She has led many observational campaigns from the ground using large telescopes (CFHT, UKIRT, VLT, etc) and has used the Infrared Space Observatory (ISO) to conduct planetary investigations.

A. Coustenis contributes to the definition and development of space missions and to the exploitation of the acquired data. She is Co-Investigator of three of the instruments (CIRS, HASI, DISR) aboard the recently completed Cassini-Huygens space mission to Saturn and Titan, in which she was involved from the beginning of the definition phase. She analyses and interprets the spectro-imaging data recovered since 2004 using her own radiative transfer codes and other analysis tools.

She has contributed in or led several other proposals, studies and development phases for space missions to the outer solar system and the exoplanets. Her expertise in space missions has allowed her to Chair or to participate in several advisory groups within ESA and NASA and other European Institutions, which, among others, currently include: Chair of the European Science Foundation Space Science Committee (ESF-ESSC); Chair of the COSPAR Panel on Planetary Protection; Chair of the ESA Human Spaceflight and Exploration Science Advisory Committee (HESAC); and, Chair of the Comité d'Evaluation sur la Recherche et l'Exploration Spatiales (CERES) of the French Centre National des Etudes Spatiales (CNES).




Full Curriculum Vitae


Dr HDR Athena Coustenis

LESIA UMR8109 (Bât. 18)
Paris Observatory,
5, place Jules Janssen, 92195 Meudon Cedex, France
Tel: +33 145077720

Professional status

Athena Coustenis is Director of Research Exceptional Class with the National Centre for Scientific Research (CNRS) of France, based at the Paris Observatory in Meudon.
Affiliation: Paris Observatory, Paris Science Letters University, CNRS, University of Paris.

Her specialization is in Planetary Sciences and Space Techniques: she works on the exploration and study of Solar System objects and of exoplanets from ground-based and space observations.

  • 1986: Master in Astrophysics and Space techniques, Univ. Paris 7 (P. & M. Curie)
  • 1987: Master in English Literature, Univ. Paris 3 (Sorbonne Nouvelle)
  • 1989: PhD in Astrophysics and Space techniques, Univ. Paris 7 (P. & M. Curie)
  • 1996: Habilitation to Direct Research (HDR), Univ. Paris 6 (P. & M. Curie).
  • LANGUAGES: French (native level), English (Proficient), Greek (native tongue), Italian (basic)
Professional History
  • Since Oct. 2022: Director of Research Exceptional class (DRCE2), of CNRS, at LESIA, Paris Observatory
  • Oct. 2019-Oct. 2022: Director of Research Exceptional class (DRCE1), of CNRS, at LESIA, Paris Observatory
  • Oct. 2013-Oct. 2019: Director of Research 1st class, CNRS, at LESIA, Paris Observatory
  • Oct. 2008-Oct. 2013: Director of Research 2nd class, CNRS, at LESIA, Paris Observatory
  • 1991-2008: Chargée de Recherche (Senior researcher) at Paris Observatory
  • 1989-1991: Post-Doc at Paris Observatory
Areas of expertise

Athena Coustenis is an astrophysicist specializing in space exploration. She works in the field of planetary sciences. Her research is devoted to the investigation of planetary atmospheres and surfaces, their origins and evolution, with emphasis on the habitable conditions in the Solar System and in exoplanets. She is involved in the definition, development and exploitation of space missions to solar system bodies with high astrobiological potential, in particular icy moons like Titan and Enceladus, Saturn’s satellites, and Jupiter’s Ganymede and Europa, but also Mars and exoplanets.

She has also led sevceral observational campaigns from the ground using large telescopes (CFHT, UKIRT, IRTF, VLT, etc) and has used the Infrared Space Observatory (ISO) to conduct planetary investigations. She analyses and interprets space and ground-based spectro-imaging data using radiative transfer codes and other analysis tools.

Beyond her scientific work, A. Coustenis is actively involved in several advisory groups within the ESA and NASA and other international bodies, helping establish the space programs and optimize their scientific return. She currently Chairs the COSPAR Panel on Planetary Protection and the Comité d'évaluation de la recherche et de l'exploration spatiale (CERES) of CNES.

Contribution to space-related projects

A. Coustenis was Co-Investigator or associated scientist, with several of the instruments aboard the NASA-ESA Cassini-Huygens space mission to Saturn and Titan. She is currently involved in three future space missions: ESA’s JUICE to the Jupiter system, JAXA’s Martian Moon Explorer (MMX) to Phobos and ESA’s ARIEL which will spectroscopically characterise transiting exoplanets. She has contributed in or led several proposals, studies and development phases for space missions to the outer solar system and the exoplanets, from the scientific, programmatic and planetary protection point of view. More in detail:

  • JUICE: Since 2009, she was involved in ESA’s JUICE mission as European Science co-
    Lead and then as member of the Science Working Team and Co-I of the JANUS camera.
    The mission will study essentially Ganymede and the Jupiter system, and has launched in
    April 2023, arrival expected in 2031.
  • ARIEL: member of the Science Definition Team and the Consortium: Selected as ESA’s Cosmic Vision M4 mission to fly in 2029.
  • MMX: Co-I on the MIRS instrument of the JAXA-led Martian Moons Exploration mission to
    launch in 2025.
  • TSSM, EJSM, Kronos, JET, E2T, etc…: In 2007 and 2008 she was the Lead European
    Scientist of the TandEM proposal to ESA which became the Titan/Saturn System Mission
    (TSSM) studied jointly by ESA and NASA. More than 150 scientists were involved in this
    project which was not selected for implementation. She has been since then actively
    involved in several other proposals to ESA and NASA. In particular, she was the European
    Co-Lead in the EJSM mission which became JUICE.
  • Deputy coordinator of H2020 and then H2024 Research Infrastructure EUROPLANET,
    Europe's leading forum for the Planetary Sciences ( Vice-
    President of the EUROPLANET Society until 2019.
  • Main coordinator of efforts towards improving or complementing molecular databases for
    planetary studies and exoplanetary data analyses (French Agence Nationale pour la
    Recherche - ANR) CH4 at Titan and e-PYTHEAS projects) involving several French laboratories and international partners.
Current research management and functions
  • President of the Comité d'Evaluation sur la Recherche et l'Exploration Spatiale (CERES) of the French Centre National des Etudes Spatiales (CNES) since 2019
  • President of the Panel for Planetary Protection (PPP) of COSPAR since 2018
  • Member ex-officio of the COSPAR Scientific Advisory Committee (CSAC) since 2014
  • Member of the Space Advisory Committee (SAC) of the Swedish National Space Board (SNSB)
  • Member of the F.R.S.-FNRS Scientific commission Sciences Exactes et Naturelles-2 (SEN-2) of Belgium.
  • Member of the Consulting Council of the Athens Observatory
  • Member of the Science Advisory Board (SAB) of the IEEC of Catalunia
  • Member of the External Scientific Advisory Board (ESAB) of the Institute of Astrophysics of Andalucia (IAA)
  • Member of the Steering Committee of NASA/NASEM Planetary Science and Astrobiology Decadal Survey 2023-2032.
  • Member of the Outer Solar System Task Group (OSSTG) of the Working Group for Planetary System Nomenclature (WGPSN) of IAU:
  • Member of the Working Group on Global Coordination of Ground and Space Astrophysics (WGGCGSA) of the IAU Executive Committee
  • Member of the Intl Astronomical Union (IAU) Executive committee of Commission F:
  • Member of the International Academy of Astronautics (IAA):
    • Chair of Section 1
    • Member of the Board of Trustees of IAA
    • Member of the IAA Scientific Activities and Publications Communication Committees
  • Associated Member Academician of the Royal Academy of Belgium, Classe des Sciences.
  • Member of the Council of the Laboratoire d’Etudes Spatiales et d’Instrumentation en Astrophysique (LESIA) of the Paris Observatory
  • Member of the Paris Science Letters (PSL) University Senate.
  • Bureau and Honorary Member of the IUGG
  • Member of the HITRAN International Committee
  • Member of the EGU Copernicus medal committee
  • Councillor of the International Society for the Study of the Origins of Life (ISSOL)
  • Member of the Editorial Board of the Chinese Space Science and Technology Journal.
  • Organiser/convener of Meetings and Planetary sessions in the international colloquia of: EGU, IUGG/IAMAS, COSPAR, AOGS, DPS, EPSC, IPPW and others.
Recent Past research management and functions (extract)
  • Chair of the Human Exploration and Science Advisory Committee (ESA-HESAC) of ESA (2018-2023)
  • President of the European Science Foundation Space Sciences Committee (ESF/ESSC) ( (2014-2020)
  • Member ex-officio of ESA’s Advisory Committee for Earth Observations (ACEO) (2018-2020)
  • Member ex-officio of the High-level Science Policy Advisory Committee (HISPAC) of ESA
  • Member ex-officio of the Space Studies Board (SSB) of the US National Academies of Science, Engineering and Medicine (2014-2020)
  • President of the International Association of Meteorology and Atmospheric Sciences (IAMAS) of the IUGG, 2011-2015. Member of the Bureau until mid-2019.
  • Member of the Science Council of Paris Observatory, 2011-2015.
  • Chair of ESA’s Solar System and Exploration Working Group (SSEWG), 2010-2013.
  • Secretary of the Committee of the Division for Planetary Sciences (DPS) of the American Astronomical Society (AAS), 2010-2014.
  • President of the Division for Planetary Sciences of the European Geophysical Union (EGU), 2009-2013.
  • Vice-Chair of the IUGG Union Commission on Planetary Sciences (UCPS):
  • Deputy coordinator of the Horizon 2024 RI EUROPLANET:
  • Chair of the Honours and Awards committee of the IUGG.
  • Chair of the EGU Jean Dominique Cassini Medal committee
  • Member of the Exec. committee of the International Space Sciences Institute 2014-2017.
  • President of the International Commission for Planetary Atmospheres and Environment (ICPAE) of the IUGG, 2003-2011.
  • Member-at-large of the Observing Program Committee of the ESO/Very Large Telescope (2001-2003) and chair of Panel C ("Stars, planets and ISM") until 2006.
  • Faculty in Post-Master courses at Paris Univ. and Ecole Doctorale Ile de France until 2017.
  • Member of the National Committee of CNRS (Jury Section 17) (2010-2012).
  • Member of the Executive committee of the Astrobiology Society
  • Member of the Editorial Board of Icarus of Elsevier ; Philosophical Transactions A of the RAS; Acta Astronautica of IAA; Astronomy & Astrophys. Reviews of Springer
  • Head Guest Editor for special issues of Planetary and Space Sciences.
  • 2023: Medal of the Académie de l’Air et de l’Espace
  • 2023: EGU Union Award: Jean Dominique Cassini Medal
  • 2019: Member correspondant du Bureau des Longitudes
  • 2019: Chevalier de la Légion d’Honneur
  • 2019: The Al Seiff Memorial Award of the International Planetary Probes Workshop
  • 2019: Honorary Member (Fellow) of the International Union of Geodesy and Geophysics
  • 2019: ARGO Award for Sciences
  • 2017: Honorary plaque from the Greek Union of Physicists
  • Associated Member of the Royal Academy of Belgium, Class of Sciences since 2016
  • Member of the International Academy of Astronautics since 2015
  • The 2014 Masursky AAS/DPS Award for meritorious service to Planetary Science
  • The 2012 Trophy for Feminine Success of the French Mediterranean Association
  • The ESA Award for making an outstanding contribution to the Huygens Probe
  • The NASA Public Service Group Achievement Award for the Descent Imager Spectrometer radiometer (DISR)
  • The NASA Public Service Group Achievement Award for the Huygens Atmospheric Structure Instrument (HASI)
  • The NASA Group Achievement Award for the Cassini Program Descent Imager Radiometer Spectrometer (DISR)
  • The NASA Group Achievement Award for the Cassini Programme Huygens Atmospheric Structure Instrument (HASI)
Scientific production and Outreach activities
  • She has written more than 260 scientific papers (H=51), with about 180 in peer-reviewed journals. She has first-authored 3 books and several chapters of Encyclopaedias.
  • Coustenis has participated in many E/PO activities. She has delivered more than 700 science talks (of which more than 150 invited in international meetings) and delivered many public lectures and conferences, including in schools.
Selected extract of publications

For the full list of publications and communications see:
A. Coustenis, full list of publications
or download this PDF:

  • Coustenis, A., Bézard, B. 1995. Titan's Atmosphere from Voyager Infrared Observations: IV. Latitudinal Variations in Temperature and Composition. Icarus 115, 126-140.
  • Coustenis, A., Salama, A. Lellouch, E., et al., 1998. Evidence for water vapor in Titan’s atmosphere from ISO/SWS data. Astron. Astrophys. 336, L85-L89.
  • Coustenis, A., Gendron, E., Lai, O., et al., 2001. Images of Titan at 1.3 and 1.6 microns with adaptive optics at the CFHT. Icarus 154, 501-515.
  • Coustenis, A., Salama, A., Schulz, B., et al., 2003. Titan’s atmosphere from ISO mid-infrared spectroscopy. Icarus, 161, 383-403.
  • Moutou, C., Coustenis, A., Schneider, J., Queloz, D., Mayor, M., 2003. Search for the HeI absorption feature in the transmission spectrum of HD209458. Astron. Astroph. 405, 341-348.
  • Coustenis, A., Hirtzig, M., Gendron, E., et al., 2005. Maps of Titan’s surface from 1 to 2.5 micron. Icarus 177, 89-105.
  • Coustenis, A., Negrao, A., Salama, A., et al., 2006. Titan’s 3-micron spectral region from ISO high-resolution spectroscopy. Icarus 180, 176-185.
  • Coustenis, A., 2007. Titan. In the Encyclopedia of the Solar System, Second Edition, P. R. Weissman, L.-A. McFadden, T.V. Johnson, Eds., Academic Press.
  • Coustenis, A., Taylor, F.W., 2008. Titan: Exploring an Earth-like World. World Scientific Press, Singapore.
  • Lavvas, P. P., Coustenis, A.,  Vardavas, I. M., 2008. Coupling photochemistry with haze formation in Titan's atmosphere. Part II: Results and Validation with Cassini/Huygens data. Plan. Space Sci. 56, 67-99.
  • Coustenis, A., Atreya, S., Balint, T., and 142 co-authors, 2008. TandEM: Titan and Enceladus mission. Experimental Astronomy 23, 893-946.
  • Coustenis, A., Jennings, D., Jolly, A., et al., 2008. Detection of C2HD and the D/H ratio on Titan. Icarus 197, 539-548.
  • Lebreton, J-P., Coustenis, A., Lunine, J., Raulin, F., Owen, T., Strobel, D., 2009. Results from the Huygens probe on Titan. Astron. & Astrophys. Rev., 17, 149-179.
  • Coustenis, A., Jennings, D. E., Nixon, et al., 2010. Titan trace gaseous composition from CIRS at the end of the Cassini-Huygens prime mission. Icarus 207, 461-476.
  • Bampasidis, G., Coustenis, A., et al., 2012. Thermal and temperature structure variations in Titan’s stratosphere during the Cassini mission. Astroph. J. 760, Issue 2, article id. 144, 8 pp.
  • Tinetti, G., Encrenaz, Th., Coustenis, A., 2013. Spectroscopic characterization of exoplanets. Astron. Astrophys. Rev., 21:63, DOI 10.1007/s00159-013-0063-6.
  • Coustenis, A., Encrenaz, Th., 2013. Life beyond Earth: the search for habitable worlds in the Universe. Cambridge Univ. Press (book), ISBN: 9781107026179.
  • Grasset, O., Dougherty, M.K., Coustenis, A., et al., 2013. JUpiter ICy moons Explorer (JUICE): an ESA mission to orbit Ganymede and to characterise the Jupiter system. Plan. Space Sci. 78, 1-21.
  • Mitri, G. Coustenis, A., et al., 2014. The Exploration of Titan with an Orbiter and a Lake Probe. Plan. Space Sci. 104, 78-92.
  • Coustenis, A., 2014. « Titan ». In Encyclopedia of the Solar System, Third Edition, T. Spohn, D. Breuer, & T. V. Johnson (Eds.), Elsevier (pp. 831–849), ISBN 9780124158450.
  • Coustenis, A., Raulin, F., 2015. “Titan Astrobiology”. Chapter in the Encyclopedia of Astrobiology, 2nd edition, M. Gargaud, R. Amils, J. Cernicharo, H. J. Cleaves II, K. Kobayashi, D. Pinti, M. Viso (Eds), Springer, 2550 p., ISBN 978-3-662-44184-8.
  • Coustenis, A., 2015. “The Cassini-Huygens mission”. Chapter in the Encyclopedia of Astrobiology, 2nd edition, M. Gargaud, R. Amils, J. Cernicharo, H. J. Cleaves II, K. Kobayashi, D. Pinti, M. Viso (Eds), Springer, 2550 p., ISBN 978-3-662-44184-8.
  • Solomonidou, A., Coustenis, A., et al., 2016. Temporal variations of Titan’s surface with Cassini/VIMS. Icarus 270, 85-99.
  • Coustenis, A., Jennings, D. E., Achterbergh, R. K., Bampasidis, G., Lavvas, P., Nixon, C. A., Teanby, N. A., Anderson, C. M., Flasar, F. M., 2016. Titan’s temporal evolution in stratospheric trace gases near the poles. Icarus 270, 409-420.
  • Encrenaz, Th., Tinetti, G., Coustenis, A., 2017. Transit spectroscopy of temperate Jupiters with ARIEL: a feasibility study. Experimental Astronomy, DOI 10.1007/s10686-017-9561-2
  • Solomonidou, A., Coustenis, A., et al, 2018. The Spectral Nature of Titan’s Major Geomorphological 1 Units: Constraints on Surface Composition. J. Geophys. Res.- Planets 123, 489-507.
  • Coustenis, A., Taylor, F.W., Plainaki, Ch., 2018. Chapter “Climate issues from the planetary perspective and insights for the Earth”. In Future Earth: The Geodetic and Geophysical Perspective. T. Beer, J. Li, K. Alverson, Eds. Cambridge Univ. Press, ISBN 9781107171596. DOI: 10.1017/9781316761489
  • Lunine, J., Coustenis, A., Mitri, G., Tobie, G. Tosi, F., 2018. Chapter “Future exploration of Enceladus and other Saturnian moons”. In “Enceladus and the Icy Moons of Saturn”. LPI/UA/Space Science Series, Eds. Paul M. Schenk, Roger N. Clark, Carly J. A. Howett, Anne J. Verbiscer, J. Hunter Waite Eds., ISBN 9780816537075.
  • Encrenaz, Th., Coustenis, A., 2018. Chapter “Atmospheres of Terrestrial Planets: Mars, Venus and Titan”. In Handbook of Exoplanets. H. J. Deeg and J. A. Belmonte, Eds. Springer.
  • A. Coustenis et al 2018. Seasonal Evolution of Titan's Stratosphere Near the Poles. ApJL 854 L30.
  • Tinetti, G., Drossart, P., Eccleston, P., Hartogh, P., Heske, A., Leconte, J., Micela, G., Ollivier, M., Pilbratt, G., Puig, L., Turrini, D., Vandenbussche, B., Wolkenberg, P., Beaulieu, J.-P., Griffin, M., Guedel, M., Min, M., Nørgaard-Nielsen, H.-U., Rataj, M., Ray, T., Ribas, I., Swain, M., Burleigh, M., Cho, J., Coudé du Foresto, V., Coustenis, A., et al., 2018. A chemical survey of exoplanets with ARIEL. Exp. Astron.,
  • Rodriguez, S., Le Mouélic, S., Barnes, J.W., Kok, J.F., Rafkin, S., Lorenz, R.D., Charnay, B., Radebaugh, J., Narteau, C., Cornet, T., Bourgeois, O., Lucas, A., Rannou, P., Griffith, C.A., Coustenis, A., et al., 2018. Observational evidence for active dust storms on Titan at equinox. Nature Geoscience 11, 727–732.
  • Jennings, D.E., Tokano, T., Cottini, V., Nixon, C.A., Achterberg, R.K., Flasar, F.M., Kunde, V.G., Romani, P.N., Samuelson, R.E., Gorius, N.J.P., Guandique, E., Kaelberer, M.S., Coustenis, A., 2019. Titan surface temperatures during the Cassini mission. Astroph. J. Lett. 877, issue 1, #L8, 6 pp.
  • Lopes, R.M.C., Wall, S., Elachi, C., Burch, S., Corlies, P., Coustenis, A., et al., 2019.  Titan as revealed by the Cassini RADAR. Space Sci. Rev. 215, issue 4, #33, 50 pp.
  • Solomonidou, A., Le Gall, A., Malaska, M.J., Birch, S.P.D., Lopes, R.M.C., Coustenis, A., et al., 2020. Spectral and emissivity analysis of the raised ramparts around Titan’s northern lakes. Icarus 344, 113413.
  • Simon, A.A., Fletcher, L.N., Arridge, C., Atkinson, D., Coustenis, A.,  et al, 2020. A review of the in situ probe designs from recent Ice Giant mission concept studies. Space Science Rev., 216, Issue 1, # id.17.
  • Coustenis, A., Jennings, D., Achterberg, R., Lavvas, P., Bampasidis, G., Nixon, C.A., Flasar, F.M., 2020. Titan’s neutral atmosphere seasonal variations up to the end of the Cassini mission. Icarus 344, 113413.
  • Hand, K.P., Sotin, C., Hayes, A., Coustenis, A., 2020. On the habitability and future exploration of ocean worlds. Space Sci. Rev. 216, Issue 5, article id.95. DOI: 10.1007/s11214-020-00713-7
  • Solomonidou, A., Neish, C., Coustenis, A., et al., 2020. The chemical composition of impact craters on Titan: Implications for exogenic processing. Astron. & Astrophys. 641, A16.
  • Ferri, F., Colombatti, G., Aboudan, A., Bettanini, C., Debei, S., Harri, A.-M., Lebreton, J.-P., Montmessin, F., Berthelier, J.-J., LeGall, A., Modolo, R., Aplin, K., Coustenis, A., 2020. The atmospheric structure of the Ice Giant planets from in situ measurements by an entry probe. Space Sci. Rev. 216, 118.
  • Coustenis, A., 2021. The Atmosphere of Titan. In Read, P. (Ed.), Oxford Research Encyclopedia of Planetary Science. Oxford University Press. DOI: 10.1093/acrefore/9780190647926.013.120
  • Coustenis, A., Witasse, O., Erd, Ch., 2021. The JUICE Mission: Challenges and Expectations. The Bridge 51.        
  • Fletcher, L.N., Simon, A.A., Hofstadter, M.D., Cohen, I., Masters, A., Mandt, K., Coustenis, A., 2020. Ice Giant System Exploration in the 2020s: An Introduction. Phil. Trans. Royal Soc. A. 378, Issue 2187, article id.20190473. DOI:10.1098/rsta.2019.0473. arXiv:2008.12125.
  • Mitri, G., Barnes, J., Coustenis, A., Flamini, E., Hayes, A., Lorenz, R. D., Mastrogiuseppe  M., Orosei, R., Postberg, F., Reh, K., Soderblom, J. M., Sotin, C., Tobie, G., Tortora, P., Vuitton, V., Wurz, P., 2021. Exploration of Enceladus and Titan: Investigating Ocean Worlds’ Evolution and Habitability in the Saturn System. Exp. Astronomy (juillet 2021), DOI: 10.1007/s10686-021-09772-2
  • Mousis, O., Atkinson, D., Ambrosi, R., Atreya, S., Banfield, D., Barabash, S., Blanc, M., Cavalié, T., Coustenis, A., et 21 co-auteurs, 2021. In Situ Exploration of the Giant Planets. Exp. Astronomy (juillet 2021),
  • Encrenaz, Th., Coustenis, A., et al., 2021. Observability of temperate exoplanets with ARIEL. Exp. Astronomy (Sept. 2021), DOI: 10.1007/s10686-021-09793-x
  • Rodriguez, S., Vinatier, S., Cordier, D., Tobie, G., Achterberg, R.K., Anderson, C., Badman, Barnes, J.W., Barth, E.L., Bézard, B., Carrasco, N., Charnay, B., Clark, R.N., Coll, P., Cornet, T., Coustenis, A., et 21 co-auteurs, 2022. Science goals and new mission concepts for a future exploration of Titan’s atmosphere, geology and habitability: Titan POlar Scout/orbiteEr and In situ DrONe fleet (POSEIDON). Exp. Astronomy,
  • Gordon, I. E., Rothman, L. S., Hargreaves, R. J., Hashemi, R., Karlovets, E. V., Skinner, F. M., Conway, E. K., Hill, C., Kochanov, R. V., Tan, Y., Wcislo, P., Finenko, A. A., Nelson, K., Bernath, P. F., Birk, M., Boudon, V., Campargue, A., Chance, K.V., Coustenis, A., et 69 co-auteurs, 2022. The HITRAN2020 molecular spectroscopic database. J. Quant. Spectrosc. Radiat. Transfer 277, article id. 107949. DOI: 10.1016/j.jqsrt.2021.107949
  • Cohen, I.J., Beddingfield, C., Robert Chancia, R., DiBraccio, G., Hedman, M., MacKenzie, S., Mauk, B., Sayanagi, K.M., Soderlund, K.M., Turtle, E., Ahrens, C., Arridge, C.S., Brooks, S.M., Bunce, E., Charnoz, S., Coustenis, A., et 21 auteurs, 2022. The case for a New Frontiers-class Uranus Orbiter: System science at an underexplored and unique world with a mid-scale mission. Plan. Sci. J., Vol. 3, Issue 3, id.58, 14 pp.
  • Mousis, O., Atkinson, D. H., Ambrosi, R., Atreya, S., Banfield, D., Barabash, S., Blanc, M., Cavalié, T., Coustenis, A., et al., 2022. In Situ exploration of the giant planets. Experimental Astronomy 54, no. 2–3, pp. 975–1013.
  • Mitri, G., Barnes, J., Coustenis, A., et al., 2021. Exploration of Enceladus and Titan: Investigating Ocean Worlds’ Evolution and Habitability in the Saturn System. Exp. Astronomy 54, Issue 2-3, p.877-910.
  • Olsson-Francis, K., Doran, P., llyin, V., Raulin, F., Rettberg, P., Kminek, G., Zorzano Mier, M. P., Coustenis, A., et al., 2023. The COSPAR Planetary Protection Policy for missions to Mars: ways forward based on current science and knowledge gaps. Life Sciences in Space Research, Vol. 36, p. 27-35.
  • Zorzano Mier, M. P., Olsson-Francis, K., Doran, P., Rettberg, P., Coustenis, A., et al., 2023. The COSPAR Planetary Protection Requirements for Space Missions to Venus. Life Sciences in Space Research, Vol. 37, 18–24.
  • Coustenis, A., Hedman, N., Doran, P.T., et al.., 2023. Planetary Protection: an international concern and responsibility. Editor’s Challenge in Planetary Science: the Future of Planetary Exploration and the Next Generation of Planetary Missions. Frontiers in Astronomy and Space Sciences - section Planetary Science. 10:1172546.






Or, how a Greek girl became a planetologist

I come from a country where people look up at the sky quite often, especially at nighttime. And from ages lost in time, they usually try to make sense of what they see. How Aristarchus invented the heliocentric solar system, how Eratosthenes proved the Earth was round and discovered the distance to the moon and how Anaximander had the Universe all structured out were my bedtime stories. And of course, I was very close to the sky myself. Not only because my name gave me rights to an Olympian abode, but also because in my family, except for my mother, we were all a little nuts about the sky: my father and brother are both in the Greek Air Force.

And I? I wanted to go higher, I wanted to be an astronaut. It wasn’t being a girl that stopped me, it never has. It was being diagnosed with severe myopia (short-sightedness) and realizing that I’d have to train in the challenging military way where the toughest part for me was getting up early in the morning… No way- I’m a night owl.

So, when I collided with books by Isaac Asimov (oh, the Foundation Series…) and Carl Sagan’s Cosmos series on TV, a new approach occurred to me (a girl has to adapt to situation changes). I could be an astronomer. I was inspired by Carl’s description of the Universe, I never missed an episode of Star Trek™ or ‘Lost in Space’ and – I was hooked. My family sort of tried to laugh me out of it. An uncle suggested that I should perhaps think of becoming an astrologer (much more money in that business). An aunt said she had a job for me in a bank (bright girl like you – you’ll catch yourself a husband in a jiffy!). I remained unmoved and unmovable. I was going away to do astronomy, the Greek Sun was not enough for me, I wanted to be where the action was and where space missions were being developed. My father finally cut me a deal: he’d let me go “do my space hobby” in France (not the US, no, no – too far away for a Greek girl of 18) if I promised to study (simultaneously) English Literature, the diploma that would be providing my real bread-and-butter some day. And (just to make doubly sure I didn’t stray far with all this free time on my hands (!?) , the deal stipulated that I had to pass all the exams in June (no second chances in September), go to Greece for three full summer months and return for the next academic year all clean, nice and rested, with my suitcase full of feta cheese and keftédes (meatballs).

So I did. I got two Masters degrees and started two Ph.D.’s with a lot of unconscious enthusiasm . I had about 250 pages of my thesis on English Horror Literature (big fan of Stephen King….) written before I finally had to quit and focus on Astronomy, much to my dismay but with relief. This came with my father’s blessings since the scholarship enabling me to continue my work had come from the French Ministry for my research at Paris Observatory in Meudon. He still encourages me to one day go back and finish my English thesis … and Stephen King still writes books, so it may happen one day…


I did my PhD at Paris Observatory in Meudon, getting my first ‘taste’ of Titan from Voyager 1 infrared data working with colleagues who since then have become good friends. Once I got a glimpse of Titan, I was hooked, bewitched, inspired and haven’t left the Outer Solar System since then… Right after my Ph.D. defense in 1989, I was engaged in three instrument proposals, all of which managed to get aboard Cassini-Huygens: CIRS on the orbiter (I knew quite a lot by then about infrared Titan spectra analysis of Titan) and HASI and DISR on the probe. I was the luckiest girl in world! The teams were fantastic, we threw ourselves into the definition of the instruments, we made observing plans and created models to be tested against the ground truth one day.

By then, the French National Center for Scientific Research had offered me a permanent position and France had become my home. I am grateful to both my mother (Greece) and host (France) countries and feel quite European. While waiting for the mission to arrive safely at its destination, of course I had to occupy myself. I went to large telescopes all over the world and observed Titan with spectra and images. I used the Infrared Space Observatory (ISO). I attacked the problem of understanding Titan from all possible perspectives: models and observations, atmospheric chemistry and surface geology, inside and out and using anything I could get my hands on…

And then one day (very early in the morning of October 1997), we watched, during one of my most memorable career and personal moments, the launch of Cassini-Huygens from Cape Canaveral… just us and the alligators waiting for their breakfast… I cried seeing the launch, I cried of joy and anticipation and thankfulness and pride to be part of this wonderful crowd of people: All the members of the teams, the ESA and NASA representatives who had us on our way to a big new adventure.

And while I was waiting for Cassini to arrive at destination, I also managed to ‘“settle down’” as my mother had long hoped for, got married to Franck, with extraordinary computer skills in his repertoire, and brought into this world my daughter, Callista (“the most beautiful” in Greek), a little star brightest than any in the sky.… Neither one of them cares very much about astronomy, but our association has worked wonders in making me happy and productive in both my personal and professional lives. It takes some organizing efforts for me to attend meetings and also be present for school and dancing shows while following all the mission’s landmarks, but it was and still is worth it.


How does one become an astronomer?

What is it like in every day life once you’ve finished your studies and managed to get a job as a researcher in this field? I recently contributed to a short movie by O. Borderie, @tmosphere en images Production.

The film “Astronomy and Space careers” (in English and in French) shows some of us who work in the field describing our “job” as an astronomer, what we do, why we became astronomers and giving some hopefully helpful hints about how to become an astronomer. Researchers, engineers and other people involved in the job of astronomy talk about their work from the inside to allow others to grasp what are the requirements in terms of studies, responsibilities, autonomy and initiatives, functional relations, specificities, environment, etc. You can also get an idea of the evolution of this craft in the future. Les métiers de l’astronomie et de l’espace by atmosphereenimages

It was fun talking about our job and how it affects our lives. We, astronomers, come from different directions, diverse backgrounds, men and women from all over the world and yet we are all linked by our passion for astronomy and a strong motivation to add a small contribution to our understanding of the Universe.

I enjoyed participating in this film, hope you enjoy it too!



What is an astrobiologist?

I came to Astrobiology quite early in my research. How could I miss the implications ‘Titan: the frozen Earth’, ‘organic chemistry closest to our planet’, the ‘methane cycle mimicking the water cycle on Earth’, etc. Of course, ancient Greek philosophers (them again !) had already thought of a universe consisting of “many worlds”. Thales, from Militos, and his students in the 7th century BCE argued for a Universe full of other planets, teaming with extraterrestrial life. They also proposed the idea with which we’re all familiar today (through Drake’s equation, among other and Carl Sagan’s musings, and the contributions of many other scientists’ arguments), i.e. that a Universe so full of stars must also have a large number of populated worlds. This proposal, was already defended by Epicurus and other Greek atomists who countered the geocentric models brought forward later on by Aristotle. The latter concept stuck, though, and hindered scientific progress in this domain for quite a long period of time. In 1862, the French scientist Camille Flammarion , published ‘La pluralité des mondes habités’ (‘on the plurality of inhabited worlds’), in which the conditions of habitability and the presence of life on such habitable planets of our Solar System is discussed. The public loved the book, but Urbain Le Verrier, then Director of the Paris Observatory , and many of his colleagues completely rejected Flammarion’s arguments, as did many of his colleagues. Flammarion was consequently fired from the Observatory… I have had better luck so far…

I’m allowed to be fascinated by the possibility that we could find information on how human beings arose and/or discover life forms elsewhere. Mars, Venus, Titan, Enceladus, Europa and other such places have been our favorite targets for exploring habitats in the Solar System and pushing current models of the origin and evolution of life to their limits, and beyond. Subsurface liquid water oceans, organic constituents swimming in exposed hydrocarbon lakes, water-laden geysers, the possibility of water hiding beneath the CO2 ice fields of Mars: All these new opportunities for exploration in the field of Astrobiology make my every day life and research work exciting and busy. Learning about and contributing to future missions to the Saturnian and Jovian systems are constant sources of joy and reward. understanding of the Universe.

And I love sharing these new findings in Astronomy with the public, always supportive and sometimes as passionate as we are… [an excerpt of this text was published in the “Pioneers in Astrobiology” section of the Astrobiology Magazine in February 2012]



Athena Coustenis was born in Athens, Greece and grew up in a garden suburb by the Saronic Bay before moving to France where she earned two Masters degrees and one PhD in Astronomy and Space Techniques (she started another PhD in English Literature and hopes to finish it one day…) thanks to a scholarship provided by the French University which furthermore allowed her to complete a Post-Doc at Paris Observatory and apply for a position with the Centre National des Recherches Scientifiques (CNRS).

Coustenis then got a permanent CNRS Researcher position at the Paris-Meudon Observatory, in the Space Lab for Space Studies and instrumentation in Astrophysics (LESIA). Paris-Meudon Observatory is the most important scientific observatory in France. The facilities at Meudon include a 36-metre tall concrete tower containing a sophisticated spectrograph for examination of the Sun. Nearby, astronomers have converted the beautiful and luxurious Chateau de Meudon into an observatory and some have even lodged there!

Meudon was named by the Gauls, who called it Mol-Dum (sand dune). It is now a suburb on the south western edge of Paris, nestled in the hills and valleys of the river Seine half way between Paris and Versailles.

Coustenis is heavily involved in the Cassini-Huygens mission to Saturn and Titan, and has used a variety of large telescopes to conduct planetary investigations on outer planet systems and exoplanets. She has written more than 100 peer-reviewed publications and has given more than 300 communications in scientific conventions and public events. She has first-authored three books.

She is leading or contributing to several advisory groups for the European Space Agency and for NASA.


Message to early career planetary scientists

with Athena Coustenis, Motivational Journeys
Episode 5, published February 20, 2020


In this interview, shot at the Geneva 2019 EPSC, I speak to Rutu Parekh of the Europlanet Early Career committee (EPEC), discussing and addressing the diversity related issues faced by early careers. As a senior researcher, I discuss my journey to become an astrophysicist, share experience and information about my course, my motivation, the challenges I faced and a message I would like to give to early careers in the field.


Legion of Honor / Ordre national de la Légion d'honneur

France, my adopted country, named me to the rank of knight of the national Order of the Legion of Honor, Chevalier de la Légion d’honneur, a distinction which is humbling to receive.

The ceremony took place on Novembre 4, 2019, at the Salle Cassini in Paris and the decoration was bestowed by the President of Paris Observatory and fellow Knight of the Legion of Honour, Dr Claude Catala.




The 2023 Jean Dominique Cassini Medal & Honorary Membership is awarded to Athena Coustenis for her major discoveries in the field of planetary atmospheres and surfaces and outstanding contribution to international space missions.




Argo Awards

On March 21, 2019, the Argo Award for Sciences was presented to Dr Athena Coustenis at a ceremony in Athens, Greece. The Argo Brussels Hellenic Network, based in Brussels, Belgium, presents these awards in eight fields of achievement from Sciences to Culture and the Arts, Entrepreneurship to Innovation, Humanitarian Contribution to Public Affairs and from Athletics to Gastronomy. Argo’s aim is to reward outwardly-directed achievement that ushers-in new horizons and to raise awareness in Greece to the successes of her native sons and daughters who live and work abroad. The event was organized under the auspices of the office of the President of the Hellenic Republic.

The 2019 Argo Awards

Dr. Athena Coustenis, astronomer specialising in space exploration (France)
Culture and Arts
Yorgos Lanthimos, film director (US)
Mary Katrantzou, fashion designer (UK)
Maria Themeli, professor of medicine (Netherlands)
Humanitarian Contribution
Dr. Auxentios Kalagos, cardiovascular surgeon and professor (Switzerland)
Contribution to Public Affairs
Andromache Karakatsani, Supreme Court Justice (Canada)
Katerina Stefanidi, Olympic medallist (US)
Konstantin Filippou, celebrity chef (Austria)

In the News (in English)
Argo Brussels Hellenic Network official website (in Greek)
Press Release (in Greek)
Dr. Athena Coustenis: interview in the Greek newspaper Ethnos (in Greek)
Dr. Athena Coustenis: interview in the Greek newspaper Ethnos (PDF in English)


The Nobel Prize in Physics 2019

Congratulations to the recipients of the 2019 Noble Prize in Physics

James Peebles
for theoretical discoveries in physical cosmology

Michel Mayor & Didier Queloz
for the discovery of an exoplanet orbiting a solar-type star

I’m so very happy that my good friends of over two decades now, Michel Mayor and Didier Queloz, were presented with the Nobel Prize for Physics in 2019. I do not know of anybody who more deserves such an award and the recognition that goes along with it for the wonderful discoveries and the hard work they have done to give life to a whole new field in Astronomy: the study of exoplanets. I had the pleasure to meet Michel in 1996, just after he and Didier had announced the discovery of the first exoplanet, 51 Pegasi b, in December 1995. We were at a meeting (the 5th International Conference on Bioastronomy, IAU Colloquium No. 161, which took place in Capri, Italy, on July 1-5 1996) and I had the immense pleasure of sitting next to Michel at dinner (see photo)… We got talking about exoplanets as at the time I was looking for signatures of the atmosphere around an exoplanet by observing 51 Peg and other exoplanets in high resolution spectroscopy using large ground-based telescopes (like the VLT). After that and for some time we worked together with Michel and Didier, along with several other colleagues, on characterising the exoplanets and thus going beyond detections, which is the purpose of the newly selected fourth medium size mission of ESA, ARIEL ( My heartfelt congratulations to Michel and Didier ! The world needs such scientists with vision and enthusiasm. Bravo et à bientôt !



Space Exploration

The Cassini-Huygens era and beyond



How exciting are these near and far future plans for the exploration of the outer solar system and even as far as the exoplanets?

Being a member of the Cassini-Huygens mission changed my life for ever… I always felt like I had boarded the spacecraft when it left and visited all these wonderful worlds on our way to Saturn, looked at the beauties of the system and landed on Titan. I’ve lived intensively every year, month and minute of that fantastic mission and wondered if anything else would happen in coming years to make me again feel so much as part of the cosmos…

How exciting are these near and far future plans for the exploration of the outer solar system and even as far as the exoplanets?

Being a member of the Cassini-Huygens mission changed my life for ever… I always felt like I had boarded the spacecraft when it left and visited all these wonderful worlds on our way to Saturn, looked at the beauties of the system and landed on Titan. I’ve lived intensively every year, month and minute of that fantastic mission and wondered if anything else would happen in coming years to make me again feel so much as part of the cosmos…

ESA's JUpiter ICy moons Explorer, JUICE

And now, we have JUICE cleared up in May 2019 to fly by the Review Board (a major milestone signifying the beginning of the qualification and production phase, taking this ESA First large mission in the Cosmic Vision program one key step closer to starting its long journey to Jupiter in 2022). Then in June 2019 Arianespace and ESA confirmed that JUICE, will be sent into space on an Ariane launch vehicle. So, we’re perfectly on our way for this mission on which I had the pleasure to work with several European and US colleagues since its beginning, about 10 years ago… There is also the NASA Europa Clipper mission with a focus on Europa, with which the JUICE team is in very close collaboration. This winning combination will afford us major breakthroughs in our understanding of the Jovian system and in particular on the habitable conditions in icy moons like Ganymede and Europa.
For more information, see:

Artist’s impression of ARIEL on its way to Lagrange Point 2 (L2). Here, the spacecraft is shielded from the Sun and has a clear view of the whole sky. Image Credit: ESA/STFC RAL Space/UCL/Europlanet-Science Office

Within this same Cosmic Vision ESA Program, we have been following the trail to planets outside the Solar System… with ARIEL, the medium-size mission selected in 2018, destined to provide us with a so much clearer and comprehensive understanding of the exoplanets via a technique called spectroscopy. I’m so proud to have been part of this mission from its earlier study phases and am very excited by its concept which will allow us study the composition and temperature of exoplanets transiting in front of their stars and get new insights on how they formed and evolved, by surveying a large sample of 1000 extrasolar planets in visible and infrared wavelengths. ARIEL will be launched in 2028 on an Ariane 6.
Check out also the Details of the ARIEL Data Challenge Series 2019 available at:

And then ESA offers the scientific community the possibility to suggest new ideas for space exploration within its Voyage 2050, the next planning cycle in ESA's Science Programme, which was launched in spring 2019 and looks via what we call “White Papers” for science themes that should be covered during this new cycle after CoCosmicmsic Vision, which covers the time period 2035-2050. Same as for calls in the US, I’m happy to say that ideas to return to Titan and Saturn after Cassini-Huygens and Dragonfly will be submitted as well as to go back to the icy giants, Uranus and Neptune, with orbiters and probes ! That would be so wonderful to follow in the footsteps of the Voyager missions (at last I would say…it’s been too long) and monitor phenomena that we been following from the ground (those magnificent storms and cloud formations…) And Triton, that so exciting other icy moon and its geysers… So many ideas will flow in for the space agencies to take on board…

So, there’s so much to look forward to in the coming years, all stay tuned !




In July 2004 the Cassini mission finally arrived at Saturn and entered into orbit around the planet, visiting the whole system. Even our wildest models and speculations hadn’t prepared us for what we’ve seen since then with instruments performing beyond our expectations. During one freezing cold night, on 15 January 2005, at Darmstadt, ESA’s Ccontrol Center in Germany, “we heard the baby cry” as Jean-Pierre Lebreton announced after the successful descent and landing of the Huygens probe. The images and all the data returned by that probe, the farthest landed man-made machine, are extraordinary and have taught us so much. Since then, many scientists and engineers around the world have participated in this extraordinary adventure by processing and analyzing the huge amount of data returned by the mission. The orbiter’s lifetime has been extended to 2017, so I’ll be busy for quite some time more. … When I think how the Voyager flyby of 1980 allowed me, a decade later, to do research not only during my Ph.D. but also for years afterwards, I have no doubt that the Cassini-Huygens data will keep several future generations of astronomers busy.

We mainly work in front of a computer if the data come from space missions. We wait for the data to be retrieved and processed at the different instruments centers. They are then sent to the team, where the people are called “co-investigators”. Each one of these has a specific expertise and a task and so they work on the data from a given point of view and produce results which are then published in a scientific journal.

If, on the other hand, we go observing at a big telescope somewhere, we then do the observations ourselves, bring back the data on a CDROM and then process them and analyze them ourselves at our institute.

It is extremely rewarding both ways, observing on a clear night from the top of a large telescope in Hawaii or Chile, or watching in awe as a space mission arrives and turns on the instruments that then send you back all the wonderful images, spectra and other data, are among the most wonderful experiences in my life…


Good-bye Cassini


Cassini-Huygens, 1997-2017

I was at Caltech in California on September 15 2017, with 1500 other people, colleagues, friends and their families, to witness the «end-of-mission» event for Cassini.

Early in the morning, at 2 am, I got up and drove to the site, the mood was of sober festivity, you might have thought we were gathering for a late night summer open air movie. Stands were handing out memorials and snacks. People were tapping others in the back, smiling,watching the big screen with friendly faces pouring out information and feelings.

Later hugs would start, after the signal got smaller and then stopped completely on the screen, hugs would be necessary to hide the tears, half of them tears of happiness that we had accomplished such a wonderful mission, the rest tears of unavoidable chagrin: after a valiant fight against Saturn’s atmosphere, Cassini’s heart stopped, and we lost a star in the sky, someone who communicated with us for more than 20 years since the launch in October 1997.

A video of the last minutes of the mission at Caltech.

Counting my years working on the mission, I realise it’s a full career time, starting since the early 1990s. First a dream, then a reality, now a souvenir. But the memory will linger on, because the notes of the voyage are still here with us, delivered until the very last moment and we will analyse them and interpret them for years to come, as we’re doing with the data from the Huygens mission.

So, good bye Cassini, you are the best ! How will we ever top such a mission? Well, we have ideas, we have new technologies and most of all we have your legacy.

Nova Lens
“Something Special Is Happening”: Cassini’s Scientists Honor Their Favorite Photos


future exploration

a look at what can be

Titan, plans

A Montgolfière for 40000 pounds…

You know by now that I’m very interested in hot-air balloons (or Montgolfière as they were called by reference to their inventors, the Montgolfier brothers who lived during the second half of the 18th century in France). I imagined them roaming around Titan, but as said before, we have to wait and see when that happens. As everyone understands these days, money is hard to come by and a study for a Titan Montgolfière would be rather costly… How much? Probably several millions of Euros. But in 1787, King Louis XVI gave a sum of 40000 English livres (or pounds) to M. de Montgolfier as an advance payment for the construction of a new aerostat (as the attached document from the French archives testifies). What would that mean in today’s money I wonder? And could it bring us closer to flying around Titan????



Titan exploration into the future

We have finally recently found out which way things are planned to go for future exploration into the Outer Solar System. The decision from the two agencies (NASA and ESA) was posted on:

As an extract:
“National Aeronautics and Space Administration and European Space Agency officials decided to continue pursuing studies of a mission to Jupiter and its four largest moons, and to plan for another potential mission to visit Saturn’s largest moon Titan and Enceladus. ”
“The [SSWG] group recommended, and NASA agreed, that both missions should move forward for further study and implementation. ”“Although the Jupiter system mission has been chosen to proceed to an earlier flight opportunity, a Saturn system mission clearly remains a high priority for the science community.”

So it seems that we may have to wait a little longer to see this mission launched, to plunge through Enceladus’ plumes, to hover over dune fields and to land in a Titan lake. No matter. The first aim of this community is to have the need for a future space mission to the outer planets recognized and transformed into reality. We may be heading for Jupiter first, but as said in the text, and as it has been well demonstrated by the reactions within this community, the public and the press, we shall need to go even further in the future.

For myself, the excitement I have felt during the past 15 months continues. During that time, I have had the immense pleasure and honor to work, exchange ideas and argue with people from all over the world over the most fascinating subject ever: a future mission to return to the Saturnian system to hunt down information on fascinating aspects like Titan’s atmosphere and surface, Enceladus geysers and Saturn’s magnetosphere. Actually, the adventure had started even earlier for me, when we were preparing the proposal for Tandem within the framework of ESA’s Cosmic Vision 2015-2025 or the study of the 2007 Flagship Titan Explorer mission. With the help and enthusiasm from friends and colleagues and in general from Titan exploration afficionados, I think I’m ready to continue towards the exploration of the Outer Solar System with a first stop at Jupiter and then on to Saturn.

Indeed, NASA and ESA have decided that TSSM studies must continue. We do not know the exact terms for this continuation yet, but we will at least set up communication paths that will allow us to stay in touch and to exchange ideas on future Titan, Enceladus and Saturn System exploration through web sites for TSSM and products.

I’m looking forward to see how best this future exploration will be implemented in the coming months.

Busy times for Outer solar system exploration

As you can see from my feature article, I am very much involved in the preparation studies for future space explo-ration of our Solar System. Besides Pluto (recently demoted to a dwarf planet to be studied NASA’s mission New Horizons), the two largest giant planets, Jupiter and Saturn (Zeus and Kronos for the Greeks…) are major targets for the coming years. Studies for two ambitious concepts were performed in 2008, one mission was called Tan-dEM/TSSM heading for Saturn’s system, and another was Laplace/EJSM, targetting Jupiter’s system, both evolving from the original proposals to ESA and NASA into fully-blown architectures for challenging science return in a col-laboration among the agencies that would have matched the excellent Cassini-Huygens achievements.

Because we can’t do everything and a space mission costs quite a lot of money (we are talking billions of $US…) one of the two systems was chosen for a space mission which will launch around 2022 and will arrive around 2030 in the jovian system…!!!

After the choice of the EJSM mission, NASA had to withdraw from the partnership and so ESA had the mission reformulated into the currently-selected concept of JUICE.

For more details on these studies and the targets, you could read the articles in 22 January 2009 Nature science magazine and some of the attached links…

I was European science Lead for the TandEM/TSSM mission and it was the most amazing experience I have had up to now, mostly because of the synergy of 150 scientists and engineers working together towards the concept described in my previous article.

I quickly became part of the Jupiter mission and had the pleasure to contribute to its formulation, definition and finally selection process by ESA. Hereafter I describe a little more the ESA-led mission which will head for the Jupiter system in 2022.


Jupiter icy moons

JUpiter ICy moons Explorer (JUICE):


The Jupiter Icy Moons Explorer (JUICE) mission was recently selected by ESA as the first large mission within the Cosmic Vision 2015-2025 plan. It is being developed to address questions regarding the Jupiter system and its satel-lites, with a focus on the largest moon, Ganymede. By thoroughly exploring the system and thereby unravelling the history of its evolution, from initial formation of the planet to the development of its satellite system, we will gain a general understanding of how gas giant planets and their satellite systems form and evolve and of how our Solar System works.

The overarching theme for JUICE is the emergence of habitable worlds around gas giants taking into account the necessary conditions involving the simultaneous presence of organic compounds, trace elements, water, energy sources and a relative stability of the environment over time. JUICE will thus address the question: Are there current habitats elsewhere in the Solar System with such necessary conditions to sustain life? The spatial extent and evolu-tion of habitable zones within the Solar System are critical elements in the development and sustainment of life, as well as in addressing the question of whether life developed on Earth alone or whether it was developed or could develop in other Solar System environments. The focus of JUICE is to characterise the conditions that may have led to the emergence of habitable environments among the Jovian icy satellites, with special emphasis on the three ocean-bearing worlds, Ganymede, Europa, and Callisto.

Titan Saturn System Mission
Cosmic Vision 2015-2025 and the candidate missions are
JUICE is Europe’s next large science mission
Jupiter Icy Moon Explorer


April 14, 2023

ESA’S JUICE (Jupiter Icy Moon Explorer)


Athena Coustenis


The JUpiter ICy moons Explorer (JUICE), 13 years in the making, finally launched on April 14, 2023 at 14:14 CEST (9:14 AM local), from the ESA spaceport in Kourou, in French Guiana. It was with immense joy that, along with several of my friends and colleagues, I had the chance to attend the launch event from the Toucan site in Kourou.

Thinking back with emotion to the time when in 2010 we recovered the Ganymede orbiter from the former NASA-ESA joint Europa Jupiter System Mission (EJSM) with, among many other colleagues, Michele Dougherty, Olivier Grasset, Emma Bunce and Christian Erd, to propose it as the JUICE mission to ESA’s Cosmic Vision 2015-2025 programme, of which it was finally adopted as the first Large mission (L1) in 2012. The instruments to go on board, with a large international participation from Europe, the US and Japan, was selected in 2013.
The mission is scheduled for an arrival in the Jovian system in mid-2031 and a nominal duration at least until 2035, but probably much more if we look at the extensions that allowed for instance for the Cassini-Huygens mission to stay in the Saturnian system for 13 years.

The launch was a fantastic event, especially since we had had to wait an extra day, after the initial launch on 13 April was postponed to the next day following a thunder alert. But on 14 April, the sky was clear and we all watched in a very emotional context, as the penultimate Ariane 5 lifted the spacecraft from pad ELA-3 at the Centre Spatial Guyanais (CSG) and then carried it safely on a perfect trajectory east out over the Atlantic Ocean, inclined just a little under three degrees to the Equator. At T+3:09 into the flight, the fairing halves separated, followed by the upper stage separation from the core stage at T+8:44. After a very short coast phase, the upper stage’s HM-7B engine ignited at T+8:49. The burn pushed JUICE, to a speed of 2.5 kilometers per second, giving the spacecraft enough energy to escape the Earth-Moon system. The upper stage shut down at T+25:25, with spacecraft separation occurring shortly after at T+27:45.

First contact with the spacecraft was achieved after some long minutes of us all watching the screen and the antenna and then JUICE’s 85 square-meter solar arrays (which are the largest solar panels ever flown on an interplanetary spacecraft) were deployed about an hour later.
In the coming days, JUICE will deploy its antennae, magnetometer, and probes.

The JUICE spacecraft is a 3-axis stabilized spacecraft, weighing 5963 kilograms at launch, that will use Venus, Earth-Moon and Earth gravity assists in its ~8 years cruise to Jupiter.

The mission will study the largest planet in our solar system and its extended system, as well as the coupling among the various components within it, including its magnetosphere. The emphasis, however, will be on three of the Galilean large moons, making detailed observations of Ganymede, Callisto and Europa with a suite of ten unique instruments + an experiment called PRIDE for and Planetary Radio Interferometer and Doppler Experiment which will make precise measurements using Radiotelescopes on Earth and a Radiation Monitor (RADEM).

With this payload, the mission will characterise the three moons both as planetary objects, highlighting their unique features, and as possible habitats investigating their astrobiological potential. It will also explore Jupiter’s complex environment in depth, and study the wider Jupiter system as an archetype for gas giants across the Universe and in other exoplanetary systems.

Juice will accomplish a number of Solar System exploration firsts. It will be the first spacecraft ever to orbit a moon other than our own – Jupiter’s largest moon Ganymede. And en route to Jupiter it will perform the first ever lunar-Earth gravity assist to save a significant amount of propellant. After 2 Europa flybys and 21 Callisto flybys, the mission will culminate in a dedicated nine months orbital tour around Ganymede during which the spacecraft will perform detailed investigations of this moon and its environment. During that phase, the orbits will include an elliptical phase, then a circular orbit at 5000 km altitude, followed by a second elliptical phase. Then, a final maneuver will put the spacecraft into a circular orbit at 500 km altitude. Mission extension through continued operations at the final or at lower orbit (target 200 km) may be feasible, depending on the how much propellant is available, and the solar array and spacecraft overall performances. Once the mission ends, JUICE will eventually impact the surface of Ganymede, in an uncontrolled way, but this is allowed by planetary protection requirements due to the fact that the large moon is considered to be in Cat. II.

The science objectives for JUICE cover a broad range of different disciplines and call for a large number of measurements. The high-level goals are to investigate the gas giant, its magnetosphere, the icy moons and their inter-relations in all their complexity. JUICE will carry out extensive new studies of Jupiter’s atmosphere and magnetosphere and their interaction with the satellites to further enhance our understanding of the evolution and dynamics of the Jovian system. A particular emphasis is on Ganymede as a planetary body and potential habitat while the mission will seek more generally to characterize the conditions that may have led to the emergence of habitable environments on the three satellites, Ganymede, Europa, and Callisto that are expected to harbor liquid water oceans underneath their surfaces. Ganymede and Europa are believed to be internally active, due to a strong tidal interaction and other energy sources.

Ganymede, the largest natural satellite in the solar system, became the main target of this space mission not only because it provides a natural laboratory for the investigation of a possible habitable world, but also because of its unique magnetic and plasma interactions with the surrounding environment and also because of the role it plays with the other Galilean satellites within the Laplace resonance.

The mission will also characterize the diversity of processes in the Jupiter system that may be required in order to provide a stable environment at the icy moons on geologic time scales, including gravitational coupling between the Galilean satellites and their long-term tidal influence on the system as a whole and this study will be enhanced with additional information gathered on Io and the smaller moons by remote sensing. The tidal response of the satellites' icy shells strongly depends on the presence of oceans. The Galilean moons are locked in a stable 1:1 spin-orbit resonance. However, slight periodic variations in the rotation rate (physical librations) and the amplitudes associated with these librations can provide further evidence for subsurface oceans. JUICE will measure precisely the rotation rate, pole-position, obliquity and libration amplitude of Ganymede. This will further constrain the dynamical history of the satellite, e.g., despinning, resonance capture, non-synchronous rotation of the icy shell, besides yielding information on the subsurface ocean and deeper interior.

The JUICE spacecraft will carry a remote sensing, geophysical, and in situ instruments specifically engineered to the challenge of talking measurements in Jupiter’s intense radiation environment. The instrumentation consists of 10 state-of-the-art instruments and one experiment that uses the spacecraft telecommunication system with ground-based instruments. The people involved in this complete payload are from many different countries and expertise, representing large scientific and engineering communities. The remote sensing suite includes imaging (JANUS) and spectral-imaging capabilities from the ultraviolet to the sub-millimetre wavelengths (MAJIS, UVS, SWI). A geophysical package consists of a laser altimeter (GALA) and a radar sounder (RIME) for exploring the surface and subsurface of the moons, and a radio science experiment (3GM) to probe the atmospheres of Jupiter and its satellites and to perform measurements of the gravity fields. The PRIDE experiment will use ground-based very-long-baseline interferometry to provide precise determination of the spacecraft position and velocity data for complementary gravity science. Particle and field investigations will be performed by the particle environment package (PEP), a magnetometer (J-MAG) and a radio and plasma wave instrument (RPWI), including electric field sensors and a Langmuir probe. This suite of instruments demonstrates the large international collaboration around the project.

The instruments on board of JUICE will allow for an investigation of the evolution and chemical composition of the surfaces and of the subsurface oceans, and enable an evaluation of the processes that have affected the satellites and their environments through time. The investigations that JUICE will conduct of the undersurface liquid water oceans in several of these bodies will lead to a better understanding of their chemical composition and the possible sources and cycling of chemical and thermal energy. It will provide the community with detailed information on how gas giant planets and their satellites form and evolve and enable an evaluation of the processes that have affected the satellites and their environments through time.

Building on previous investigations by space missions and ground-based observatories, JUICE is expected to revolutionize our understanding of the Jovian system. As with previous such large endeavors, JUICE is an international mission: NASA has contributed the UVS instrument and hardware for two European-provided instruments, while JAXA has contributed hardware for various of the European-provided instruments.

The complex system around Jupiter is a privileged target of several space missions and ground-based observations starting with the Juno mission in 2016 and continuing with JUICE, while Europa Clipper is being implemented to fly in 2024 and arrive in 2030. The detailed JUICE characterization of the wider Jovian system will extend Juno’s focused study of Jupiter’s interior and inner magnetosphere. Juno’s observations will be very helpful for the in situ measurements by JUICE and Europa Clipper.

JUICE and Europa Clipper will certainly provide original and ground-breaking results when associating their monitoring of the Jovian system elements on the planet’s atmosphere, magnetospheric and plasma environment, as well as of the exospheres of the icy moons. Having two spacecraft at the same time around Jupiter will also improve the ephemerides of the Galilean moons, thus improving the knowledge of the dynamics, resonances and internal dissipation in the Jovian system.

I wanted to say a huge thanks to the whole JUICE team, the leads, the SWT, the PIs, the project and in particular Olivier Witasse, Giuseppe Sarri, Nicolas Altobelli, Claire Vallat and everyone working on this mission for the past 13 years! Hoping to get a glimpse of the arrival in mid 2031 and looking forward to the joint observations and breakthroughs by the JUICE and Europa Clipper missions!

Artist's rendition of JUICE arriving at the Jupiter system (ESA)

With Josef Aschbacher (ESA DG) and Daniel Neuenschwande (Director/Space Transportation)
on site at Kourou in the Jupiter Hall before the launch.

With Hauke Hussmann (JUICE GALA PI), and Paul Hartogh (SWI PI).

With Claire Vallat (Operation Scientists for the JUICE mission)

With PIs and Team Members of the MAJIS instrument and Günther Hasinger, former ESA Science Director.

With Thierry Bred-Dibat, Pascale Ultré-Guerard and Olivier La Marle



Juice just left! Happy…

With the PIs of the different instruments on JUICE.





Science notes


Life Beyond Earth:
The Search for Habitable Worlds in the Universe

my new book

It all started with Therese and I getting interested in exoplanets, the (still) new field in astronomy dealing with the planets discovered (about 1000 by now) around other stars than our Sun. And also my long-lived passion for Astrobiology, the study of habitable worlds in our solar system and beyond. Looking at how life might have emerged on other planets, seeking to evaluate to potential for hosting life and supporting its development under the surfaces of outer plant satellites in deep oceans of liquid water, and trying to define what makes an environment potentially habitable are some things I have been working on ever since my interest in Saturn’s moons Titan and Enceladus and in some of the Galilean satellites like Europa and Ganymede. Satellites turn out to be great places for looking for habitable conditions (liquid water, organic chemistry, energy sources, etc).

So, we decided to look at the problem from a different perspective: from that of astronomers, planetologists, who don’t know much about biology but would like to share their understanding of where life could possibly emerge and be able to survive.

If you want to know more, attached to this entry are some of the current reviews by Journals and Magazines.

We hope the book and its different point of view will add something to the current available literature which abounds since Astrobiology and Exoplanetology are relatively new interdisciplinary fields but vey attractive ones for all kinds of experts: biologists, geologists, atmospheric physicists, astronomers, climatologists, etc…

Links about the book Life Beyond Earth:


Funny things happening around Saturn
how does an astronomer work?

We all know by now that Titan is fantastic… ;-) But did you know that other wonderful worlds are evolving around the Lord of the Rings (Kronos, Saturn, whatever you want to call the giant planet).

Just a few days ago, my next favorite moon, Enceladus, gave us new cause for wonder. Enormous plumes of water spurt in giant jets out of deep cracks we call “tiger’s stripes” in the South pole of the satellite. Researchers now provide evidence that the plumes originate in an underground salty ocean.

This is extremely important in the quest of astrobiologists for the origins and evolution pathways that lead to life in our Solar System and elsewhere, because in that, liquid water is essential. So that now we know that liquid water can exist as far as 10 Astronomical Units (10 times the distance of Earth to the Sun). An there are strong suspicions also that Titan harbors a liquid water ocean also… This is really wonderful news also for our understanding about how the moons in the Solar System are formed and how they have evolved in time.

You may want to also see: Salty Ocean In The Depths Of Enceladus

Stay tuned for more amazing discoveries around Saturn and in the meantime you may want to go and see the new movie Startrek and watch closely for something related to our discussions

(see also: Have you found it? And how do you like the new movie?)



Events notes



Landmark International Project
focusing on the power of interdisciplinary cooperation
towards solutions for the climate and energy issues on Earth

ALPHA MISSION -ΔELOS 1st seed gathering


ALPHA MISSION - ΔELOS events are synthesized on an approach of interdisciplinary gathering, connecting mythology, art and science
by people who want to exchange ideas, to learn from one another and to find a way towards a better future for our planet and for humanity.

The main events take place on the Greek island of Delos.
Delos is a place that still has a mission today, inspiring people as the mythical birthplace of Apollo and Artemis
but also as a model city for sustainability, to also take care of our roots and assist in the healing of planet Earth.


Island of Delos

03/06/2023: Delos island: Third Delos Global Gathering, highlighting the power of interdisciplinary and intersectional cooperation for the protection of life on Earth. Read more
30/03/2023: St. Elisabeth, Berlin, an evening for the regeneration of the Earth. Screening of of the May 2022 Concert. Read more
30/01/2023: UNESCO headquarters, Paris: Starting point for a major conversation on climate crisis, culture and the future of humanity. Read more
17/11/2022: European Parliament: Screening of the May 2022 concert. Read more
30/05/2022: Delos Island: ALPHA MISSION – ΔELOS & The [uncertain] Four Seasons Inaugural Concert. Screening of the May 2022 concert. Read more
24/06/2021: Delos island: ALPHA MISSION – ΔELOS seed gathering. Delos island. Read more


2023 event, Island of Delos

Athena Coustenis
speaking at the event
June 4, 2023
on the island of Delos

2023 event, Island of Delos

2023 event, Island of Delos

Athena Coustenis
speaking at the event
January 30, 2023

2022 event, Island of Delos

2022 event, Island of Delos

2022 event, Island of Delos

The 2023 Third Delos Global Gathering, highlighting the power of interdisciplinary and intersectional cooperation for the protection of life on Earth was held on the island of Delos on June 3d and 4th.

The meeting was attended by 70 leading representatives of science, education, space technology, arts, environment, philosophy and inner development.

Among the speakers were Costas Synolakis – Μember of US National Academy of Engineers, natural hazards professor, Mark Moffet – Tropical biologist, ecologist, story teller, Farooq Chaudhry – OBE, co-founder & Producer, Akram Khan Company, John Tasioulas – Director of the Institute for Ethics in AI, University of Oxford, Athena Coustenis – Astrophysicist, Planetologist at Paris Observatory-PSL, Marshall Marcus – CEO, European Union Youth Orchestra, Marianne Poncelet – Executive Vice-President, International Yehudi Menuhin Foundation, Richard Dunne – Founder & director, the Harmony Project, Indra Adnan – Founder, The Alternative Global, Gary Bolles – Author, Chair for the Future of Work, Singularity University, Kiran Bir Sethi – Designer, Founder, Riverside School, Brent Sherwood – Senior vice president, Advanced Development Programs for Blue Origin and Akram Khan – MBE, dancer, choreographer.

One of the most special moments of the gathering was the performance of “Peaux” by Iannis Xenakis from Pleiades. The internationally acclaimed Greek percussion soloist Dimitris Desyllas with his ensemble “TYPANA” in front of the island’s emblematic lions performed the work with unique power, symbolizing the deep connection between ancient myths, art and human creativity.



On 30 May, 2022, the emblematic Greek island of Delos -the cosmopolitan centre of the Mediterranean in antiquity, now an open museum- comes to life again! This date will mark the official launch of ALPHA MISSION – ΔELOS. A collective initiative that combines the strengths of Mythology, Art and Space Technology to raise awareness globally about the urgent need for the regeneration of our planet.

For the first time in its thousands of years of history, Delos welcomes a classical music orchestra for a broadcast concert of an international scope and great symbolic value. The European Union Youth Orchestra (EUYO), together with Ukrainian & Russian musicians, and soloists the Ukrainian born rising star Diana Tishchenko (violin) and Greek virtuoso Sokratis Sinopoulos (lyra) will perform the concert entitled “The [uncertain] Four Seasons”, a concert especially created to underscore the uncertainty about the future of our planet if we do not act urgently.

The concert will be live-streamed (19:30 CET) on ARTE, on the social-media platforms of Cultural and Technological institutions, and projected live onto big screens in Megaron the Athens Concert Hall and various European cities. It will additionally be broadcast on ARTE’s Sunday TV concert on 5 June -17.25 (CET) in Germany and 18.25 (CET) in France. The concert will be available on from 30th May until end of August and will then travel around the world. The event also marks the 30th anniversary of ARTE, the important European cultural channel, symbol of Franco-German friendship.

The ALPHA MISSION - ΔELOS concert is a co-production of the World Human Forum & ARTE in partnership with Europa Nostra, the Hellenic Space Center, the National Research Center for Natural Sciences “Demokritos", the Hellenic Foundation for Culture, Megaron the Athens Concert Hall - and in collaboration with the Ephorate of Antiquities of Cyclades. The EUYO is artistic partner of the event.

ALPHA MISSION - ΔELOS in a nutshell: NASA’s ARTEMIS MISSION will take the first woman to the Moon by 2025, following the APOLLO MISSION which took the first man to the moon in 1969. Delos is the island where, according to the myth, the twin gods Apollo and Artemis were born, and where light was born. For many centuries in antiquity, Delos was the cosmopolitan centre of the Mediterranean. Today, the whole island is an open museum and the ancient ruins on it are already affected by the climate crisis and rising sea level. Parallel to our quest to explore space, Delos -and the events connected to it- will be emblematic reminders that wings also need roots and that the healing of our planet should be a priority. NASA’s Artemis Mission, following the Apollo Mission, gives us the unique opportunity to understand that Humanity will not succeed in addressing the challenges we face unless we combine the wisdom of the past with the knowledge and possibilities of today, humanities with science, mythology, art and spirituality with space and technology.

The program consists of Vivaldi’s The Four Seasons, improvised episodes for Lyra, Carmen Fizzarotti’s Floating Autumn from “The [uncertain] Four Seasons” and Marshall Marcus’ 17 Strokes of the Bell for Peace and Sustainability.

The EUYO will be welcomed by the lyra, the modern continuation of Apollo’s instrument with a 3000-year history that will masterfully intertwine with the work of Vivaldi and the concert’s contemporary composers.

Carmen Fizzarotti’s Floating Autumn from The [uncertain] Four Seasons, is an algorithmic re-composition of Vivaldi’s ‘Autumn’. Developed by composers, musicians, climate and computer scientists using geospatial climate predictions for 2050, it depicts what a future world might feel like if we do not reverse biodiversity loss by 2030. The [Uncertain] Four Seasons is an initiative of AKQA and Jung von Matt, composer Hugh Crosthwaite, Sydney Symphony Orchestra and the Monash Climate Change Communications Research Hub.

The European Union Youth Orchestra, cultural ambassador for the European Union, represents the European ideal of a community working together to achieve peace and social understanding. Founded in 1976 by Lionel and Joy Bryer following a unanimous vote of the European Parliament, with Maestro Claudio Abbado as its Founding Music Director, it brings together the most talented young musicians from all EU member states united by a shared sense of European heritage, innovation, sustainability, and the constant pursuit of excellence. Together with Russian and Ukrainian musicians it represents the voice of the youth of Europe. The EUYO's Honorary President is the President of the European Parliament and its Honorary Patrons are the Heads of State and Prime Ministers of each of the EU member states, headed by the President of the European Commission.

The soloist, violinist Diana Tishchenko, of Ukrainian origin, is amongst the most exciting young artists of recent years and has won several international competitions for her musicality and technical mastery, and posseses musical imagination far beyond her years. She has been a guest on major international concert stages.

Greek musician Sokratis Sinopoulos is a contemporary master of the lyra, a bowed instrument that dates back to ancient times. His playing is delicate and nuanced yet highly expressive, and his proficiency on the instrument has been widely acclaimed. Sinopoulos has collaborated with numerous musicians throughout the world. He is equally comfortable crossing genre boundaries into jazz and classical, as he is to staying true to folk traditions of Greece and Eastern Mediterranean.



Space is cool


Solar Orbiter Launch
Kennedy Space Center, February 10, 2020

So, this was my third launch and the second one at Cape Canaveral more than 22 years after Cassini in 1997! As I walked to the viewing deck it all came back: the excitement, the perfect night (this time with a full moon!), the colleagues and friends, the expectations…. and the alligators in the river in front of us… And the Atlas V far away with our mission on top… A mission to the selection of which I contributed back in 2011 when I was Chair of the Solar System and Exploration Working Group of ESA and fought for it to be recognised as the first possible medium-class mission within the Cosmic Vision Program.

The two hours of waiting after arrival went by so fast, I didn’t even realise we were counting down from 4 minutes and launch being authorised and everything « go » and looking out above the dark ocean to the launch pad and then the phenomenal blast illuminating the sky and the mission rising, simingly, to a perfect rendez-vous with the Moon…

Every launch is a lifetime experience, so I am grateful for being there… in person, for a monumental moment that I’ll cherish... and then the Sun


A video of the launch from my mobile.


GRAVITY: The Journey To And From Earth

I’m sure you’ve all seen the movie GRAVITY, otherwise you’re not really so interest in space or such rocket-freaks as I am. If you haven’t, what follows includes spoilers… Some of my friends who saw it said it was excellent but hated the suspense. Others the ending, my friend Isabelle hated the disappearance of Clooney so soon, but then again Isabelle so looooooves Clooney (which is why she and I are still good friends, I’m simply craaaaaazy about Pitt and Cruise…)
But I digress…

The movie moved me (sorry about the pun) a lot, and apologies to all, I loved it all – start, middle and ending. Also Sandra Bullock is a favorite of mine and she’s so real and such a great actress (how does she manage to keep so fit?). So, first of all, after having endured the suspense (congrats to the authors for managing to keep us interested with basically only one actor and void throughout the film… I wasn’t bored one second…) it’s always nice to have a happy ending. And what ending ! Coming out of the water, learning to walk… what a great analogy with humankind’s first steps, emerging from the oceans, learning to breathe and slowly rising on their two legs and learning how to use them… Never mind how she managed to land on one small tiny little bit of water pond…

Even a scientist like me can ignore some of the possible strays from real facts because the purpose here is to show than humans can survive anywhere: In space and on all kinds of extreme environments on Earth. See my recent book with Therese Encrenaz, published by Cambridge University Press, in which we discuss “Life Beyond Earth: the search for habitable worlds in the Universe”. And maybe the reason why we look for them is not only about finding other life forms, but also about discovering other places where humanity could move and inhabit when our Sun turns into a Red Giant and other places that could teach us how life emerged and how to survive in strange environments.

And even if the Clooney ghost and lost little girl melodrama do not add to the facts, I cried my eyes out with them which proves it’s a good movie, a healthy movie because humans like to get emotional in space, I know I would if I had a chance to fly out there, but I won’t – short-sighted you see… Although, in a Radio show recently someone asked me if I’d like to go to space and the same answer came out again, the one I don’t have to think about: “yes, I’d like to go, but only if I were sure not to return”. Returning takes up so much of your energy that it seems to me you won’t be able to appreciate the trip. I’d like to just sit back in a cabin and spend hours reading and contemplating the wonders in our Solar System, not having to worry about oxygen supply and lift-off and re-entry and landing and all of those things that make a space mission so cumbersome and impossible in some cases. But perhaps I’d do that only after I’m 90 or so, I’d like to take advantage of life on Earth and my family in the meantime. But maybe they won’t take me in NASA when I’m old and decrepit – I’ll have to get Sandra to give some hints about keeping fit…
But I digress again…

I’m sure we’ll land on Mars some day and we may be capable of exploring or even terraforming other planets or satellites – that’s why I got so interested in Titan in the first place: can it be a different kind of Earth that could teach us so much about our planet and life occurrence just by changing perspectives? But the most important thing, as Ulysses (Odysseus in reality) would put it, is the journey – the journey to Ithaca, the journey from Earth to planets (and back for some). Humans can do it!


Listen to C. Kavafis: Enjoy the journey !

by Constantine P. Kavafis (1911)

When you set out on your journey to Ithaca,
pray that the road is long,
full of adventure, full of knowledge.
The Lestrygonians and the Cyclops,
the angry Poseidon — do not fear them:
You will never find such as these on your path,
if your thoughts remain lofty, if a fine
emotion touches your spirit and your body.
The Lestrygonians and the Cyclops,
the fierce Poseidon you will never encounter,
if you do not carry them within your soul,
if your soul does not set them up before you.

Pray that the road is long.
That the summer mornings are many, when,
with such pleasure, with such joy
you will enter ports seen for the first time;
stop at Phoenician markets,
and purchase fine merchandise,
mother-of-pearl and coral, amber and ebony,
and sensual perfumes of all kinds,
as many sensual perfumes as you can;
visit many Egyptian cities,
to learn and learn from scholars.

Always keep Ithaca in your mind.
To arrive there is your ultimate goal.
But do not hurry the voyage at all.
It is better to let it last for many years;
and to anchor at the island when you are old,
rich with all you have gained on the way,
not expecting that Ithaca will offer you riches.

Ithaca has given you the beautiful voyage.
Without her you would have never set out on the road.
She has nothing more to give you.

And if you find her poor, Ithaca has not deceived you.
Wise as you have become, with so much experience,
you must already have understood what Ithacas mean.

The Day the Earth Smiled at Saturn

On 19 July 2013, my favorite space mission, Cassini, turned its cameras and took a picture of the Earth, of us, of all of us fitting us in a pixel. This has happened before a couple of times, but this is the first time we, Earth people, knew in advance that this could happen, that our picture would be taken from one and a half billion km away, and that between 23:27 and 23:42 this past Friday, some of us were outside smiling and waving at Saturn. This “interplanetary photo op” worked well I hear, as people gathered among colleagues, friends or family and had their picture taken by one of the most sophisticated cameramen out there at the moment.


And as Carl Sagan, a mentor I very much miss, said:

“Consider again that dot. That’s here. That’s home. That’s us. On it everyone you love, everyone you know, everyone you ever heard of, every human being who ever was, lived out their lives. The aggregate of our joy and suffering, thousands of confident religions, ideologies, and economic doctrines, every hunter and forager, every hero and coward, every creator and destroyer of civilization, every king and peasant, every young couple in love, every mother and father, hopeful child, inventor and explorer, every teacher of morals, every corrupt politician, every “superstar,” every “supreme leader,” every saint and sinner in the history of our species lived there – on a mote of dust suspended in a sunbeam.

The Earth is a very small stage in a vast cosmic arena. Think of the rivers of blood spilled by all those generals and emperors so that in glory and triumph they could become the momentary masters of a fraction of a dot. Think of the endless cruelties visited by the inhabitants of one corner of this pixel on the scarcely distinguishable inhabitants of some other corner. How frequent their misunderstandings, how eager they are to kill one another, how fervent their hatreds. Our posturings, our imagined self-importance, the delusion that we have some privileged position in the universe, are challenged by this point of pale light. Our planet is a lonely speck in the great enveloping cosmic dark. In our obscurity – in all this vastness – there is no hint that help will come from elsewhere to save us from ourselves.

The Earth is the only world known, so far, to harbor life. There is nowhere else, at least in the near future, to which our species could migrate. Visit, yes. Settle, not yet. Like it or not, for the moment, the Earth is where we make our stand. It has been said that astronomy is a humbling and character-building experience. There is perhaps no better demonstration of the folly of human conceits than this distant image of our tiny world. To me, it underscores our responsibility to deal more kindly with one another and to preserve and cherish the pale blue dot, the only home we’ve ever known.”

—Carl Sagan, Pale Blue Dot: A Vision of the Human Future in Space, 1997 reprint, pp. xv–xvi

In the future, there should also be another such photo op by the Messenger mission around Mercury…

...reactions from around the world:

Paris:‘I just smiled in the darkness of the Paris night thinking of you all! Thinking of these rare moments when at last, we, human beings, breathe in the consciousness of our universality.’

Unknown:‘I had my Arms out in a big Y … telling the universe I loved it, and glad I am a part of it. Felt Fantastic. Nice to be a part of something bigger than myself.’

Madrid:‘Felt very connected for we are all the same Human family.’

Lake Ontario: ‘The thought that a camera was taking pictures from so very far away IS just incredible. We may not be unique… we may be transient… we may be only flying along on a dust mote. But darn it, for 15 minutes we were there, we were aware, and we smiled.’

Unknown:‘Thanks.It was a wonderful way to bring the world together.’

Unknown:‘One awesome moment in history and I am soooo chuffed to have been a part of it. Gave me goosebumps it did, the thought of everyone taking part.’

Malaysia: ‘I got up specially at 5.27 am to give a wave, just to say ‘I was there!’ Luckily none of the locals saw me!’

South England: ‘At the appointed time, I raised a glass of fine red wine, and [my daughter] a glass of fizzy pop. We said ‘cheers’ to Saturn, To Cassini, to each other. Then smiled, laughed, waved and cheered and took photos of ourselves. Both beaming! It was perfect.’

Germany: ‘I tock a moment to marvel over the acomplichments of ouer species, how far we have come, and how far we can go if we just work together:)’

British Columbia: ‘It was great feeling … the same “oneness” as thousands of others all around the globe smiled in sync.’

US Eastern Seaboard: ‘What a feeling of connection and oneness with the miracle that is life on Earth. This experience was beyond meaningful. It was transcendent. What a beautiful thing.’

Unknown:‘I usually smile a lot, but today it felt even better!And thinking there is really something flying around Saturn taking pics from earth is really overwhelming! Thanks a lot! ‘

The Day Earth Smiled


Astronomy picture of the day