Ten years ago last January 14, 2005, a space probe was sent to check on Titan, Saturn’s largest moon, and to explore what’s behind those thick mists that perpetually enveloped the enigmatic satellite.
Nobody knows anything about Titan until Huygens started taking pictures and sending them back to earth via its mother ship Cassini. On its way down to the moon’s surface, carried by a parachute, it was blown by strong winds and it was oscillating back and forth like a pendulum. It was greeted by a rugged terrain of frozen rocks, black rivers of chemicals composed of liquid ethane, methane and several other hydrocarbon particles.
The probe landed with a tender thud, all 319 kilograms of it. It was relatively light considering the weak gravitational pull of the moon. The European Space Agency was behind the space project. And the landing is the farthest ever achieved by man. Unless of course somebody else manage to send a probe as far as Uranus or Neptune or the Krueger Belt where the once planet Pluto now belonged since it was downsized to what is called icy worlds.
For 72 minutes, Huygens kept on taking pictures and sending valuable pictures and other data not before Cassini totally disappeared from the horizon. Huygens’s batteries eventually drained out. Nevertheless, that short window was enough to deliver a deep understanding about this moon.
“We didn’t know what we would land on, whether it would be solid ice as hard as granite or a liquid sea,” says Professor John Zarnecki of the Open University, who was the lead scientist on the probe’s Surface Science Package, which was one of six instrument suites onboard Huygens. “So for ESA the primary mission was to make measurements of the atmosphere. Survival on the surface was always going to be an added bonus.”
And it was certainly a bonus. The team have a hunch that Huygens hit a pebble before settling down. Round pebbles are only found where there is a steady flow of liquid over rocks. The liquids will polish the rock’s rough edges by their scraping movements. Definitely, liquid was flowing at the landing place of Huygens one time or another. Maybe as recent as 10 to 15 years before. Huygens may have landed in a flood plain or a seasonal type of lake.
“Cassini and Huygens have done a fantastic job showing what a varied place Titan is,” Zarnecki tells Astronomy Now. “In some ways it is incredibly frustrating because although the mission has been an enormous success, we have just got to go back and do a lot more stuff because Cassini has shown how varied the surface is. There are dunes, cryo-volcanoes, river systems, lakes. Titan has absolutely lived up to the hype.”