A European spacecraft landed on the Saturn moon Titan Friday for the first close-up look of a celestial body scientists say may give clues to what Earth might have been like billions of years ago. The spacecraft pierced Titan's murky atmosphere and revealed a world of coastlines and drainage channels.
After a seven year ride to Saturn on the U.S. Cassini spacecraft, the European Space Agency's Huygens probe finally reached its destination, the surface of the mysterious moon Titan, the only moon in the solar system with an atmosphere. The agency's director general, Jean-Jacques Dordain, hailed the feat as a fantastic success for Europe and for international space cooperation.
"We are the first visitors [to] Titan and scientific data that we are collecting now shall unveil the secrets of this new world," he said.
Huygens separated from Cassini on Christmas Day and moved gradually in free fall toward Titan for the final, blazing two-and-a-half hour descent Friday at 28,000 kilometers per hour. It deployed two parachutes to slow it and a heat shield to protect it from searing friction with the moon's atmosphere.
Its mission was to collect data on the obscuring atmosphere, whose thick methane and nitrogen composition is believed to have been similar to that of the young Earth before life appeared. It also was to reveal Titan's hidden surface for the first time. Scientists have speculated that it is a blend of rock, methane ice and chemical lakes.
Now, the first images relayed through the Cassini mothership confirm the suspicions. Mission scientist Martin Tomasko of the University of Arizona says they show features such as shorelines and channels for flowing liquid. He described the flow as more like seepage from canyon walls rather than rivers.
"We suspected there would be liquid on the surface of Titan,” he said. “We suspected that we would see things that look like drainage channels and shorelines. We've never been able to see them with this clarity."
The European Space Agency's science director, David Southwood, was exultant, saying Huygens’ first pictures of Titan delight him.
"I just wanted to know that there was complexity down there, that this really was a world that was going to yield totally new science,” he explained. “I'm now convinced we're going to do it. For me, it's the end of a wonderful day."
To the delight of mission controllers, Huygens survived its impact on Titan and continued to transmit data far longer than the two hours they had predicted. Its batteries were designed for seven hours of operation, but officials feared the moon's extremely frigid temperature of -180 degrees Celsius might sap them, especially if the probe landed in chilly liquid. However, missions operations chief Claudio Sollazzo says data sent back shows that the interior of Huygens was a hospitable 25 degrees Celsius, thanks to thick foam insulation.
"This is an important thing because maybe it gives us some explanation of the long life on [the] ground, because it was so warm inside that it could survive longer than we expected," he noted.
Mission officials say scientists will pore over the data from Huygens' plunge for months, looking for clues that might help them understand how life originated in a similar environment on the young Earth. In the meantime, the Cassini spacecraft is returning to its normal orbit to continue its four-year mission to study Saturn.