Cassini Week: Huygens Probe 

When Cassini launched in 1997, it carried with it a special payload: a probe named Huygens that would penetrate the permanent haze of Saturn’s largest moon Titan, and reveal to us the shrouded world below.

Huygens descent module and shield

Huygens descent module and shield – Credit: ESA

And what a world Titan is!

It’s larger than Mercury, approaching the diameter of Mars (Titan: 5,150 km / Mars: 6,780 km). It has an atmosphere with superrotating winds, composed of 95 nitrogen and 5% methane. And it has an abundance of massive liquid methane lakes and rivers, as well as water ice and rocks of all sizes. A truly dynamic place that can only be referred to as a world.

And we owe most of what we know about Titan thanks to Huygens and Cassini.

Four images obtained at different altitudes during Titan's descent

Four images obtained at different altitudes during Titan’s descent – Credit: ESA/NASA/JPL/University of Arizona

The probe was named after the man who discovered Titan in 1655, the Dutch astronomer Christiaan Huygens.

Christiaan Huygens

Christiaan Huygens

After a seven year journey, Cassini entered Saturn’s orbit on July 1, 2004. On Christmas Day of that year (Spacecraft Event Time), the shelled Huygens probe separated from Cassini and began its three-week coast to Titan’s surface. Finally, on January 14, 2005, Huygens fell through Titan’s atmosphere, slowed by parachutes, for 2 hours and 27 minutes, before landing on the surface. On the way down, its suite of instruments and cameras captured priceless data about the mysterious world on which it would spend the rest of its life.

First color photo from Titan's surface

First color photo from Titan’s surface – Credit: NASA/JPL/ESA/University of Arizona

Huygens sent data back from the surface of Titan for 72 minutes, before Cassini–our relay station to the probe–dipped below the moon’s horizon. The amount of data collected and transmitted during that short time, however, was phenomenal. In addition to the breathtaking photos, Huygens provided us with unprecedented data about the alien moon, data that is still being analyzed for new discoveries to this day.

Stay tuned for more, as we continue our week of commemorating the Cassini mission on the eve of the spacecraft’s Grand Finale.

Cassini’s Grand Finale

On September 15, one of the most fruitful space missions ever imagined will come to an end. After two decades in space, Cassini’s fuel supplies are close to being depleted. To avoid contaminating one of Saturn’s moons, including a pair that could harbor life–Enceladus and Titan–the decision was made to retire Cassini into Saturn’s atmosphere. Up until contact between the orbiter and Earth is lost, Cassini will continue to study our beloved ringed planet. New insight will be gleaned from this mission that’s only made possible by Cassini’s fatal approach to the gas giant. Among the data to be collected:

  • The spacecraft will make detailed maps of Saturn’s gravity and magnetic fields, revealing how the planet is arranged internally, and possibly helping to solve the irksome mystery of just how fast Saturn is rotating.
  • The final dives will vastly improve our knowledge of how much material is in the rings, bringing us closer to understanding their origins.
  • Cassini’s particle detectors will sample icy ring particles being funneled into the atmosphere by Saturn’s magnetic field.
  • Its cameras will take amazing, ultra-close images of Saturn’s rings and clouds.

Cassini launched on Oct. 15, 1997. After a seven-year journey the orbiter arrived at Saturn, carrying the European Space Agency’s Huygens probe. In 2005, the probe successfully landed on Saturn’s largest moon, Titan.


Quick facts about Titan:

  • Titan is the solar system’s second largest moon.
  • It’s the only moon in our solar system that has cloud systems and a dense, planet-like atmosphere.
  • Titan has liquid hydrocarbon lakes, mountains, and seasonal weather patterns.

For 13 years, Cassini has orbited Saturn and provided us with fascinating information about, not just the planet, but its intricate ring system and many moons.

Cassini mission overview infographic

Cassini mission overview infographic – Click for larger version – Source: NASA/JPL

In addition to the important scientific data that was collected by Cassini, are the breathtaking images that have been collected: storms and aurorae on Saturn, detailed views of the worlds that are Saturn moons, and remarkable visions of Saturn’s sensational rings.

For the next week, we celebrate Cassini’s achievements.

Still from the short film Cassini's Grand Finale, the spacecraft is shown diving between Saturn and the planet's innermost ring.

Still from the short film Cassini’s Grand Finale, the spacecraft is shown diving between Saturn and the planet’s innermost ring. – Credit: NASA/JPL-Caltech