Abstract
Titan, Saturn's largest moon, is the only Solar System planetary body other than Earth with a thick nitrogen atmosphere. The Voyager spacecraft confirmed that methane was the second-most abundant atmospheric constituent in Titan's atmosphere, and revealed a rich organic chemistry, but its cameras could not see through the thick organic haze. After a seven-year interplanetary journey on board the Cassini orbiter, the Huygens probe was released on 25 December 2004. It reached the upper layer of Titan's atmosphere on 14 January and landed softly after a parachute descent of almost 2.5 hours. Here we report an overview of the Huygens mission, which enabled studies of the atmosphere and surface, including in situ sampling of the organic chemistry, and revealed an Earth-like landscape. The probe descended over the boundary between a bright icy terrain eroded by fluvial activity—probably due to methane—and a darker area that looked like a river- or lake-bed. Post-landing images showed centimetre-sized surface details.
This is a preview of subscription content, access via your institution
Access options
Subscribe to this journal
Receive 51 print issues and online access
$199.00 per year
only $3.90 per issue
Buy this article
- Purchase on SpringerLink
- Instant access to full article PDF
Prices may be subject to local taxes which are calculated during checkout
Similar content being viewed by others
References
Smith, P. H. et al. Titan's surface revealed by HST imaging. Icarus 119, 336–349 (1996)
Meier, R., Smith, B. A., Owen, T. C. & Terrile, R. J. The surface of Titan from NICMOS observations with the Hubble Space Telescope. Icarus 145, 462–473 (2000)
Gibbard, S. G. et al. Titan: high-resolution speckle images from the Keck telescope. Icarus 139, 189–201 (1999)
Coustenis, A. et al. Maps of Titan's surface from 1 to 2.5 µm. Icarus 177, 89–105 (2005)
Porco, C. C. et al. Imaging of Titan from the Cassini spacecraft. Nature 434, 156–165 (2005)
Campbell, D. B., Black, G. J., Carter, L. M. & Ostro, S. J. Radar evidence for liquid surfaces on Titan. Science 302, 431–434 (2003)
Lebreton, J.-P. & Matson, D. L. The Huygens probe: science, payload and mission overview. Space Sci. Rev. 104, 59–100 (2002)
Matson, D. L., Spilker, L. J. & Lebreton, J.-P. The Cassini-Huygens mission to the saturnian system. Space Sci. Rev. 104, 1–58 (2002)
Fulchignoni, M. et al. The characterisation of Titan's atmospheric physical properties by the Huygens Atmospheric Structure Instrument (HASI). Space Sci. Rev. 104, 395–431 (2002)
Bird, M. K. et al. The Huygens Doppler Wind Experiment—Titan winds derived from probe radio frequency measurements. Space Sci. Rev. 104, 613–640 (2002)
Israel, G. et al. Huygens probe aerosol collector pyrolyser. Space Sci. Rev. 104, 433–468 (2002)
Niemann, H. B. et al. The gas chromatograph mass spectrometer for the Huygens probe. Space Sci. Rev. 104, 553–591 (2002)
Zarnecki, J. C. et al. Huygens' surface science package. Space Sci. Rev. 104, 593–611 (2002)
Tomasko, M. G. et al. The Descent Imager/Spectral Radiometer (DISR) experiment on the Huygens entry probe of Titan. Space Sci. Rev. 104, 469–551 (2002)
Fulchignoni, M. et al. In situ measurements of the physical characteristics of Titan's environment. Nature doi:10.1038/nature04314 (this issue)
Clausen, K. C. et al. The Huygens probe system design. Space Sci. Rev. 104, 155–189 (2002)
Pogrebenko, S., et al. in Proceedings of the International Workshop: Planetary Probe Atmospheric Entry and Descent Trajectory Analysis and Science (6–9 October 2003, Lisbon) (ed. Wilson, A.) 197–204 (ESA SP-544, ESA Publications Division, Noordwijk, 2004)
Bird, M. K. et al. The vertical profile of winds on Titan. Nature doi:10.1038/nature04060 (this issue)
Tomasko, M. G. et al. Rain, winds and haze during the Huygens probe's descent to Titan's surface. Nature doi:10.1038/nature04126 (this issue)
Zarnecki, J. C. et al. A soft solid surface on Titan as revealed by the Huygens Surface Science Package. Nature doi:10.1038/nature04211 (this issue)
Niemann, H. B. et al. The abundances of constituents of Titan's atmosphere from the GCMS instrument on the Huygens probe. Nature doi:10.1038/nature04122 (this issue)
Israël, G. et al. Complex organic matter in Titan's atmospheric aerosols from in situ pyrolysis and analysis. Nature doi:10.1038/nature04349 (this issue)
Waite, H. et al. Ion neutral mass spectrometer results from the first flyby of Titan. Science 308, 982–986 (2005)
Atkinson, D. H., Kazeminejad, B., Gaborit, V., Ferri, F. & Lebreton, J.-P. Huygens probe entry and descent trajectory analysis and reconstruction techniques. Planet. Space Sci. 53, 586–593 (2005)
Kazeminejad, B. Methodology Development for the Reconstruction of the ESA Huygens Probe Entry and Descent Trajectory. PhD thesis, Karl-Franzens Univ. (2005)
Kazeminejad, B. & Atkinson, D. H. The ESA Huygens probe entry and descent trajectory reconstruction. In Proceedings of the International Workshop: Planetary Probe Atmospheric Entry and Descent Trajectory Analysis and Science (6–9 October 2003, Lisbon) (ed. Wilson, A.) 137–149 (ESA SP-544, ESA Publications Division, Noordwijk, 2004)
Kazeminejad, B. et al. Simulation and analysis of the revised Huygens Probe entry and descent trajectory and radio link model. Planet. Space Sci. 52, 799–814 (2004)
Lorenz, R. D. & Mitton, J. Lifting Titan's Veil (Cambridge Univ. Press, Cambridge, UK, 2002)
Raulin, F. & Owen, T. Organic chemistry and exobiology on Titan. Space Sci. Rev. 104, 377–394 (2002)
Schulze-Makuch, D. & Grinspoon, D. H. Biologically enhanced energy and carbon cycling on Titan. Astrobiology 5(4), 560–567 (2005)
Acknowledgements
The Cassini-Huygens mission is the result of an exemplary international collaboration in space exploration. Huygens involved more than 40 European industries and two US suppliers. The work of the members of the Cassini and Huygens teams from ESA, NASA/JPL, the Huygens industrial consortium led by Alcatel, and all Cassini-Huygens investigators is acknowledged. We especially acknowledge the Cassini orbiter teams that made their early observations available in advance to Huygens, and to R. Yelle for his leadership in coordinating the Titan Atmosphere Model Working Group. Special acknowledgements to B. Smeds for his work in designing and managing the Huygens link test that allowed the Doppler problem to be detected and solved, to L. Popken for his modelling of the Huygens Digital Radio Receiver and to the whole Huygens recovery task force led by K. Clausen and L. Deutsch. We thank K. van't Klooster for his efforts to initiate and promote the Huygens VLBI experiment, and J. Louet for his support. The Earth-Based Huygens Doppler tracking experiment is led by W. Folkner. We appreciated the support provided by the National Radio Astronomy Observatory (NRAO), operated by Associated Universities Inc., under a cooperative agreement with the NSF, and the one provided by the Australia Telescope National Facility (ATNF) managed by CSIRO. We also thank M. Bird, R. Lorenz, R. A. Preston and J. C. Zarnecki for a careful reading of various versions of the manuscript and for providing comments.
Author information
Authors and Affiliations
Corresponding author
Ethics declarations
Competing interests
Reprints and permissions information is available at npg.nature.com/reprintsandpermissions. The authors declare no competing financial interests.
Supplementary information
Supplementary Figure 1
This figure shows an exploded view of the Huygens probe. (PDF 47 kb)
Supplementary Figure 2
This figure shows the accelerometer measurements (engineering sensors) during the whole descent. (PDF 79 kb)
Supplementary Figure 3
This figure shows the evolution of the probe internal temperature measurement during the descent and on the surface. (PDF 60 kb)
Supplementary Figure 4
This figure illustrates the overall variation of the communication radio link parameter during the mission and provides a comparison between the predicted signal envelope and the measured signal strength, both during the descent (probe spinning) and on the ground. (PDF 65 kb)
Supplementary Figure 5
This figure shows the location of all the radio telescopes that were used to receive the Huygens carrier signal. The telescope configuration is shown as seen from Titan at the beginning (left panel) and at the end (right panel) of the observation. (PDF 48 kb)
Supplementary Figure 6
This figure shows the path of the direct signal transmitted by Huygens and of the one reflected by the ground. The two signals produces an interference pattern that was detected on board Cassini. (PDF 47 kb)
Supplementary Notes
This includes Supplementary Table 1 (details about the six Huygens investigations), Supplementary Table 2 (a list of 17 radio telescopes that were part of the Huygens radio astronomy segment of the mission), Supplementary Figure Legends and technical information about the probe that was not appropriate to include in the printed version. It also describes the technical details of the radio astronomy segment of the Huygens mission. (DOC 65 kb)
Rights and permissions
About this article
Cite this article
Lebreton, JP., Witasse, O., Sollazzo, C. et al. An overview of the descent and landing of the Huygens probe on Titan. Nature 438, 758–764 (2005). https://doi.org/10.1038/nature04347
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1038/nature04347
This article is cited by
-
Planetary Radio Interferometry and Doppler Experiment (PRIDE) of the JUICE Mission
Space Science Reviews (2023)
-
Enceladus and Titan: emerging worlds of the Solar System
Experimental Astronomy (2022)
-
In-vacuum active colour sensor and wireless communication across a vacuum-air interface
Scientific Reports (2021)
-
Chemical and Isotopic Composition Measurements on Atmospheric Probes Exploring Uranus and Neptune
Space Science Reviews (2020)
-
The Atmospheric Structure of the Ice Giant Planets from In Situ Measurements by Entry Probes
Space Science Reviews (2020)