The Cassini-Huygens mission is a NASA/ESA/ASI mission to explore the Saturnian system. The ESA component consists largely of the Huygens probe, which entered the atmosphere of Saturn's largest moon, Titan, and descended under parachute down to the surface. The Cassini spacecraft is undertaking an extensive exploration of the Saturnian system with its rings and many satellites. Cassini completed its initial four-year mission to explore the Saturn System in June 2008 and the first extended mission, called the 'Cassini Equinox Mission', in September 2010.
A second extended mission, called the 'Cassini Solstice Mission' will continue until September 2017; this will allow scientists to study the Saturnian system until the summer solstice is passed in May 2017. By the time this new extension is completed the Cassini mission will have covered (since it arrived in the system) one half of a Saturnian year.
The Cassini-Huygens mission is designed to explore the Saturnian system and all its elements: the planet and its atmosphere, rings and magnetosphere, and a large number of its moons, particularly Titan and the icy satellites.
The exploration of Titan is at the very heart of the Cassini-Huygens mission. Titan encounters are used for making the gravity-assist orbit changes that shape the orbital tour around Saturn. During each Titan fly-by, the Orbiter will perform a set of in orbit and remote sensing observations of the surface, the atmosphere and the plasma environment.
The detailed atmosphere descent data set acquired by the Probe and the global coverage that will be provided by the Orbiter observations during targeted fly-bys will provide a unique wealth of new scientific information. It will substantially increase our knowledge of Titan, the enigmatic planet-sized moon shrouded by a thick, hazy and chemically active atmosphere.
Following the successful landing of Huygens it is anticipated that further details on the surface and possibly the interior of Titan will be discovered.
Christiaan Huygens (1629-1695), was a Dutch astronomer who discovered Saturn's rings and, in 1655, its largest moon Titan.
NASA's Saturn orbiter is named after the French/Italian astronomer Jean-Dominique Cassini, who discovered several Saturnian satellites and a number of ring features, including the eponymous Cassini division, during the period 1671-1685.
Built by an industrial consortium led by Aerospatiale, the Probe System comprises two principal elements:
- the 318 kg Huygens Probe, which enters Titan's atmosphere after separating from theSaturn Orbiter;
- the 30 kg Probe Support Equipment (PSE), which remains attached to the Orbiter after Probe separation.
The Probe itself consists of the Entry Assembly (ENA) cocooning the Descent Module (DM). The ENA provides Orbiter attachment, umbilical separation and ejection, cruise and entry thermal protection, and entry deceleration control. It is jettisoned after entry, releasing the Descent Module.
The DM comprises an aluminium shell and inner structure containing all the experiments and Probe support subsystems, including the parachute descent and spin control devices.
The PSE consists of:
- four electronic boxes aboard the Orbiter: two Probe Support Avionics (PSA), a Receiver Front End (RFE) and a Receiver Ultra Stable Oscillator (RUSO)
- the Spin Eject Device (SED)
- the harness (including the umbilical connector) providing power and RF and data links between the PSA, Probe and Orbiter.
To reach Saturn, Cassini-Huygens used a series of gravity-assist manoeuvres, with the following swing-bys:
- 27 April 1998 - Venus
- 24 June 1999 - Venus
- 18 August 1999 - Earth
- 30 December 2000 - Jupiter
Mission and Science Operations from Jet Propulsion Laboratory, Pasadena. Communication through NASA's Deep Space Network.
Operations are managed by the Huygens Probe Operations Center (HPOC), located in ESOC, Darmstadt, Germany.