They are visions of a unique family of worlds on the other side of the solar system: a moon with lakes of liquid methane: a tiny, rocky world with geysers of water that are being sprayed into space and a strange mottled moon that has been splattered with dark, organic-rich gunk, like a comedian who has been hit by a custard pie.

These bizarre sets of images were released last week as Nasa, and the European Space Agency, Esa, prepare to celebrate the 10th anniversary of the launch of their Cassini-Huygens probe to Saturn. Blasted into space on 15 October, 1997, the probe took seven years to reach Saturn. Since then, the robot spacecraft has been delivering stunning photographs of the ringed planet and its fantastic family of moons. 'The launch was the start of one of space exploration's great adventures and we didn't really know what we would find,' said Professor Andrew Coates, of University College London, who heads one of the UK teams involved in Cassini. 'Now we are reaping the rewards of nearly 20 years' work on the mission and the science continues to be amazing.'

The mission's most spectacular moment occurred in December 2004, when its tiny Huygens probe separated from its mother craft, Cassini, and headed towards Saturn's main satellite, Titan, the only moon in the solar system with an atmosphere. Several weeks later, it parachuted down to a landing on its surface and returned close-up images of this weird, distant world.

Huygens stopped working after only a few hours, as expected, but Cassini has continued to survey Saturn and its moons - with startling results. In the case of Iapetus, it has helped solve - or at least partly solve - a 300-year-old scientific mystery. Astronomers had noted the little moon darkened and lightened as it moved round Saturn but couldn't work out why.

Now Cassini has helped provide the answer. Dark, organic-rich material is splattering the face of Iapetus as it orbits Saturn, like a car whose windscreen is sprayed with water from other cars on a rainy day.

'Dusty material spiralling in from outer moons [of Saturn] hits Iapetus head-on, and causes the forward-facing side of Iapetus to look different than the rest of the moon,' said Tilmann Denk, a Cassini team member based at the Free University, Berlin. Which moon is responsible for imposing this indignity on Iapetus remains unknown, however.

In addition, Cassini radar images have shown that both poles of Titan are pitted with hydrocarbon lakes, one of them larger than Lake Superior, Earth's largest freshwater lake. 'This is our version of mapping Alaska, Canada, Greenland, Scandinavia and northern Russia,' said Rosaly Lopes, of the Jet Propulsion Laboratory, Pasadena. 'It's like mapping these regions of Earth for the first time.'

Titan's north pole is currently gripped by winter. And quite a winter it is, with temperatures dropping to -180C and a rain of methane and ethane drizzling down, filling the moon's lakes and seas. These liquids also carve meandering rivers and channels on the moon's surface.

Finally, last week Nasa and Esa revealed images from Cassini which confirmed that jets of fine, icy particles are spraying from Saturn's moon Enceladus and originate from a hot 'tiger stripe' fracture that straddles the moon's south polar region. The discovery raises the prospect of liquid water existing on Enceladus, and possibly life.

'These are findings with tremendously exciting implications,' said Carolyn Porco, of the Space Science Institute in Boulder, Colorado. 'Do the jets derive from near-surface liquid water or not? And if not, then how far down is the liquid water that we all suspect resides within this moon?'