TALISE would paddle across Titan's vast hydrocarbon sea...,

nationalgeographic | Titan's allure is manyfold: It has a thick atmosphere—the only moon in the solar system to have one—stable liquid on its surface, and a landscape of lakes, seas, and dunes. So it's no surprise that astronomers are keeping an eye on Saturn's largest satellite.

Scientists now say the Huygens probe that landed on Titan in 2005 did so with a bounce, slide, and wobble, yielding new clues about its Earthlike terrain.

Meanwhile, a Spanish team has proposed sending a boatlike probe that could paddle or propel itself across Ligeia Mare, a vast, liquid hydrocarbon lake near Titan's north pole. The inspiration for the probe's design includes Mississippi River paddleboats and an amphibious Soviet vehicle with screwlike propellers.

"We thought, why not be capable of moving after landing so you can study the landing site, cruise to the shore, and explore the shore?" said Igone Urdampilleta, an aerospace engineer with SENER, a private Spanish engineering firm.

SENER is developing the design—presented at the European Planetary Science Congress in Madrid in September—with Madrid's Centro de Astrobiología.

The still conceptual probe, called the Titan Lake In-situ Sampling Propelled Explorer (TALISE), would take both liquid and soil samples to learn more about Titan's organically rich environment.

Titan Atmosphere Like "Oil Refinery"

Imagine a world shrouded in an orange-brownish fog where it rains methane, the temperature is minus 290 degrees Fahrenheit (nearly 180 below zero Celsius), and a year lasts 29.5 Earth years.

"If you were to bottle some of Titan's atmosphere, then opened the bottle on Earth, it might smell a bit like an oil refinery," said Titan expert Ralph Lorenz of the University of Arizona. "Titan is so much colder, [so] what might be sticky goop on Earth is literally rock hard on Titan."

By the same token, methane and ethane—components of natural gas on Earth and thought to be prevalent on Titan—would exist in liquid form there.  According to Lorenz, scientists are "99-plus percent" certain that Ligeia Mare consists mostly of liquid ethane and methane, with the lake stretching several hundred meters across and at least 33 feet (10 meters) deep.