Land Ho! Huygens Plunged to Titan Surface 5 Years Ago

Land Ho! Huygens Plunged to Titan Surface 5 Years Ago

The full version of this story with accompanying images is at:
http://www.jpl.nasa.gov/news/features.cfm?feature=2448&cid=feature_2448

The Huygens probe parachuted down to the surface of Saturn's haze-shrouded
moon Titan exactly five years ago on Jan. 14, 2005, providing data that scientists on
NASA's Cassini mission to Saturn are still building upon today.

"Huygens has gathered critical on-the-scene data on the atmosphere and surface of
Titan, providing valuable groundtruth to Cassini's ongoing investigations," said Bob
Pappalardo, Cassini project scientist at NASA's Jet Propulsion Laboratory.

The Huygens probe, built and managed by the European Space Agency, was bolted
to Cassini and rode along during its nearly seven-year journey to Saturn. Huygens'
descent marked mankind's first and only attempt to land a probe on another world
in the outer solar system.

Huygens transmitted data for more than four hours, as it plunged through Titan's
hazy atmosphere and landed near a region now known as Adiri. Atmospheric
density measurements from Huygens have helped engineers refine calculations for
how low Cassini can fly through the moon's thick atmosphere.

Huygens captured the most attention for providing the first view from inside
Titan's atmosphere and on its surface. The pictures of drainage channels and
pebble-sized ice blocks surprised scientists with the extent of the moon's similarity
to Earth. They showed evidence of erosion from methane and ethane rain.

"It was eerie," said Jonathan Lunine, an interdisciplinary Cassini scientist at the
University of Rome, Tor Vergata, and University of Arizona, Tucson, and was with
the Huygens camera team five years ago as they combed through the images
coming down. "We saw bright hills above a dark plain, a weird combination of light
and dark. It was like seeing a landscape out of Dante."

Combining these images with detections of methane and other gasses emanating
from the surface, scientists came to believe Titan had a hydrologic cycle similar to
Earth's, though Titan's cycle depends on methane and ethane rather than water.
Titan is the only other body in the solar system other than Earth believed to have
an active hydrologic cycle.

Huygens also gave scientists an opportunity to make electric field measurements
from the atmosphere and surface, revealing a signature consistent with a water-
and-ammonia ocean under an icy crust.

While the Huygens probe itself remains inactive on the Titan surface, insights
inspired by the probe continue and ESA has convened a conference this week to
extend the discussion, said Jean-Pierre Lebreton, Huygens Project Scientist for ESA.

"Huygens was a unique, once-in-a-lifetime mission," he said. "But we still have a lot
to learn and I hope it will provide guidance for future missions to Titan."

The Cassini-Huygens mission is a cooperative project of NASA, the European Space
Agency and the Italian Space Agency. JPL, a division of the California Institute of
Technology in Pasadena, manages the Cassini mission for NASA's Science Mission
Directorate, Washington, D.C. JPL designed, developed and assembled the Cassini
orbiter. Huygens data was sent to NASA's Cassini spacecraft, and was recorded and
relayed to Earth by NASA's Deep Space Network. JPL also manages the Deep Space
Network.

Jia-Rui C. Cook 818-354-0850
Jet Propulsion Laboratory, Pasadena, Calif.
jia-rui.c.cook@jpl.nasa.gov

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