Cassini-Huygens Overview

The Cassini spacecraft was launched on October 15, 1997. After a journey of nearly 7 years it entered orbit around Saturn on July 1, 2004. Since then Cassini has been exploring the planet, its rings, and its moons, including the deployment of a probe to the moon Titan--a world with an atmosphere sufficient to allow a parachute to land the probe on its surface

The Cassini spacecraft, composed of the orbiter and the Huygens probe, is the second largest interplanetary spacecraft ever to be launched, due to its cargo of multiple science instruments and an enormous quantity of fuel.

The Cassini mission is an international cooperative effort of NASA, the European Space Agency, and the Italian Space Agency. This NASA/European partnership provides an example of an undertaking whose scope and cost would not likely be borne by any single nation, but is made possible through shared investment and participation. Hundreds of scientists and engineers from 16 European countries and 33 U.S. states made up the teams that designed and fabricated the Cassini spacecraft. At the University of Kansas, two Dept. of Physics and Astronomy faculty members are associated with this mission: Prof. Thomas Cravens, a member of the INMS (Ion and Neutral Mass Spectrometer) team, and Prof. Emeritus Thomas Armstrong, a co-investigator of the MIMI (Magnetospheric IMaging Instrument) experiment.

The Huygens Probe

Huygens is designed to study the atmosphere and surface of Titan, Saturn's largest moon, by conducting detailed in-situ measurements of the physical properties, chemical composition and dynamics of the atmosphere and local characterisation of the surface. It is a highly sophisticated robotic laboratory carrying six scientific instruments. Huygens is the element contributed by ESA to Cassini/Huygens, the joint NASA/ESA dual-craft mission to the Saturnian system. NASA has provided the Saturn Orbiter. The overall mission is named after the French/Italian astronomer Jean-Dominique Cassini, who discovered several Saturnian satellites and ring features (the Cassini division) in 1671-1685. The Probe is named after Dutch astronomer Christiaan Huygens, who discovered Titan in 1655.

Click here to see the Huygens Probe Descent Video
NASA - Titan - A View from Huygens - Jan. 14, 2005 - Movie

The exploration of Titan is at the very heart of the Cassini/Huygens mission. The Orbiter will make repeated targeted close flybys of Titan, gathering data about the moon and making gravity-assisted orbit changes that will allow it to make a tour of the satellites, reconnoitre the magnetosphere and obtain views of Saturn's higher latitudes. During its 4-year nominal mission, Cassini will make detailed observations of Saturn's atmosphere, magnetosphere, rings, icy satellites and Titan. The detailed in-situ data set acquired by the Probe and the global data set from the Orbiter's tour will undoubtedly provide a unique wealth of information that will substantially increase our knowledge of Titan, a fascinating planet-sized moon shrouded by a thick, hazy and chemically active atmosphere.

The Cassini Orbitor

The Cassini spacecraft is loaded with an array of sophisticated instruments and cameras, to deliver valuable data from the mission to scientists around the world.

In many ways, the spacecraft's instruments can be classified to the way human senses operate. Your eyes and ears are "remote sensing" devices because you can receive information from remote objects without being in Cassini Spacecraft direct contact with them. Your senses of touch and taste are "direct sensing" devices. Your nose can be construed as either a remote or direct sensing device. You can certainly smell the apple pie across the room without having your nose in direct contact with it, but the molecules carrying the scent do have to make direct contact with your sinuses. Cassini's instruments can be classified as remote and microwave remote sensing instruments, and fields and particles instruments. These are all designed to record significant data and take a variety of close-up measurements.

However, the instruments on the Cassini spacecraft are much more advanced than our own. Cassini can "see" in wavelengths of light and energy that the human eye cannot. The instruments on the spacecraft can "feel" things about magnetic fields and tiny dust particles that no human hand could detect.

The remote sensing instruments can calculate measurements from a great distance. This set includes both optical and microwave sensing instruments including cameras, spectrometers, radar and radio.

The fields and particles instruments take direct sensing measurements of the environment around the spacecraft. These instruments measure magnetic fields, mass, electrical charges and densities of atomic particles. They also measure the quantity and composition of dust particles, the strengths of plasma (electrically charged gas), and radio waves.

2004 Mission Milestones:

Jun. 11, 2004: Cassini takes the first detailed images of tiny, battered Phoebe, a small moon on the edge of the Saturn system. The images and data are gathered at a range of 2,068 kilometers (1,285 miles).

Jul. 1, 2004: Cassini zips across Saturn's ring plane and settles into Saturn's gravitational grip - the first spacecraft to orbit the giant planet. The initial spectacular images of the rings reveal new details about their composition and structure.

Oct. 26, 2004: Cassini makes its first close pass by Titan. Cruising by at a distance of only 1,200 kilometers (750 miles), the spacecrafts radar provides the first detailed glimpses of the moon's mysterious surface.

Dec. 25, 2004 (UTC): The European Space Agency's Huygens probe separates from the Cassini orbiter and begins its 21 day journey to Titan. Dec. 25 counts as day one and Jan. 14 is day 21.

Dec. 31, 2004: Cassini caps off an amazing first year with a flyby of icy Iapetus, snapping the first close-up images of the battered moon

2005 Saturn Tour Highlights:

Jan. 14, 2005: The European Space Agency's Huygens probe descended through Titan's cloudy atmosphere, touching down on the surface about two and half hours later.

Feb. 15, 2005: Cassini makes another pass by Titan and it's first pass by Enceladus.

Mar. 9, 2005: Cassini flies within 504 kilometers (313 miles) of icy Enceladus.

Mar. 31, 2005: Cassini flies by Titan and Enceladus.

Sep. 26, 2005: Cassini studies Hyperion at a range of 1,010 kilometers (628 miles), the closest approach ever to the tiny moon. It is Cassini's only visit to the moon during the primary mission.

Oct. 11, 2005: Cassini turned its instruments on Dione from a distance of 500 kilometers (311 miles).

Nov. 26, 2005: Cassini passed within 500 kilometers (311 miles) of Rhea.

2006 Saturn Tour Highlights:

Jan. 15, 2006: Titan flyby -- the first solar occultation occurs, giving scientists the chance to see the sun shining directly through the atmosphere of Titan

Jan. 17, 2006: Flyby of Rhea -- one of the best non-targeted flybys of this icy moon in the tour, this pass complements last November's targeted flyby.

Feb. 27, 2006: Titan flyby -- these are the first of four coordinated Radio Science flybys that explore the interior of Titan. T22, T33, and T38 are the others. T11 is the flyby that occurs when Titan is near apoapsis, and the spacecraft flyby is at a low inclination

Mar. 19, 2006: Titan flyby -- the first Radio Science bistatic (bouncing a signal off the surface and returning it to Earth) and occultation (sending the radio signal through the atmosphere of Titan to the Earth) observations.

Mar. 21, 2006: Flyby of Rhea -- one of the closer non-targeted flybys of Rhea, this pass will display Rhea at a large phase angle, highlighting craters and topography.

Apr. 30, 2006: Titan flyby -- a shared closest approach between the Ultraviolet Imaging Spectrograph (UVIS) with another stellar occultation probing the atmosphere of Titan at a different latitude, and RADAR, exploring another interesting swath of the surface of Titan. Interestingly, we haven't had a RADAR observation since October 28, 2005.

May 20, 2006: Titan flyby -- the second Radio Science bistatic (bouncing a signal off Titan's surface and returning it to Earth) and occultation (sending the radio signal through the atmosphere of Titan to the Earth) flyby of the mission.

Jul. 2, 2006: Titan flyby -- this occurs two years to the date from our first detailed glimpse of Titan at T0. Titan is in an unusual position relative to the incoming solar wind, sun, and Saturn, which make this a particularly interesting flyby for the magnetospheric instruments who will control the pointing of the spacecraft up to closest approach, one of only two flybys in the whole mission where they do that. After closest approach, we turn the spacecraft over to the infrared instrument CIRS, which is probing the atmosphere.

Jul. 22, 2006: Cassini's orbit gets rotated out of the plane of the rings with this Titan encounter -- the start of the "Titan 180 transfer."

Sep. 9, 2006: Enceladus non-targeted, and Methone (perhaps closest in the mission) flybys occur.

Sep. 15, 2006: Cassini views the Sun as is passes behind Saturn and the rings. The rate of passage through the rings is very slow and the view will yield information on the D and C rings that is impossible at any other time in the tour.

Nov. 9, 2006: Enceladus non-targeted -- views of south pole from about 125,000 kilometers (about 77,700 miles).

Dec. 12, 2006: Titan flyby -- this flyby has a shared closest approach between a UVIS stellar occultation at a different latitude, INMS sniffing the atmosphere and RADAR exploring the surface.

Dec. 28, 2006: Titan flyby -- this flyby is the second of four coordinated radio science flybys exploring the interior of Titan (T11, T33, and T38 are the others). T22 is the flyby that occurs when titan is again near apoapsis, but the spacecraft flyby is at a high inclination.

Cassini at Saturn - January 10, 2007- Video From JPL

Credit: Nasa/JPL/ESA