title: An overview of the descent and landing of the Huygens probe on Titan.
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.
authors.affiliation: Research and Scientific Support Department, ESA Science Directorate, ESTEC, 2200 AG, Noordwijk, the Netherlands. jean-pierre.lebreton@esa.int
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: Lebreton
authors.forename: Olivier
authors.initials: O
authors.lastname: Witasse
authors.forename: Claudio
authors.initials: C
authors.lastname: Sollazzo
authors.forename: Thierry
authors.initials: T
authors.lastname: Blancquaert
authors.forename: Patrice
authors.initials: P
authors.lastname: Couzin
authors.forename: Anne-Marie
authors.initials: AM
authors.lastname: Schipper
authors.forename: Jeremy B
authors.initials: JB
authors.lastname: Jones
authors.forename: Dennis L
authors.initials: DL
authors.lastname: Matson
authors.forename: Leonid I
authors.initials: LI
authors.lastname: Gurvits
authors.forename: David H
authors.initials: DH
authors.lastname: Atkinson
authors.forename: Bobby
authors.initials: B
authors.lastname: Kazeminejad
authors.forename: Miguel
authors.initials: M
authors.lastname: Pérez-Ayúcar