Fwd: 10 years since Titan landing

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From: "Gary Johnson" <gjohnson144@comcast.net>
Date: January 15, 2015 at 9:27:23 PM CST
To: "Gary Johnson" <gjohnson144@comcast.net>
Subject: FW: 10 years since Titan landing

 

 

10 years since we landed on Titan

January 14, 2015 by Keith Cooper

Ten years ago today, on 14 January 2005, a compact, flattened cylinder called Huygens, chock-full of sensors, cameras and scientific experiments, went hurtling through the orange skies of the mysterious moon Titan.

An artist's impression of Huygens on the surface of Titan. Image: ESA/C Carreau.

The surface of Titan was still largely unknown at the time, hidden behind a veil of dense smog produced by a haze of hydrocarbon aerosols, but all was about to be revealed. As its parachutes unfurled, Huygens was buffeted by winds, swaying on its ropes as the surface loomed up, a terrain of craggy ice-rocks and the dark tributaries belonging to rivers formed from a black, oily chemical mix of liquid ethane, methane and other hydrocarbon molecules. Then came touchdown, the 318 kilogram probe reduced to a relative featherweight in Titan's light gravitational touch. On the surface, Huygens fired pictures of its new surroundings, relayed by way of its mothership Cassini, back home to Earth and the eagerly awaiting throngs of scientists and press, to confirm that the European Space Agency had successfully accomplished the most distant landing ever achieved. Until we send something to land on one of the moons of Uranus or Neptune, or a body in the Kuiper Belt, this record will not be broken.

Huygens spent 72 minutes transmitting data from the surface of Titan before the relaying station – Cassini – disappeared over the horizon (Huygens' batteries died soon thereafter). Yet in that short time it provided a profound view of this alien 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."

What a bonus though. Zarnecki's team suspect that Huygens hit a pebble before touching down on softer, icy gravel. Round pebbles are formed by the action of liquid flowing over rocks (or rock-hard chunks of ice, in this case), smoothing their edges through abrasion. Clearly liquid had flowed over Huygens' landing site at some point, perhaps only ten or fifteen years earlier. Huygens had come down in either a floodplain or a dried-up seasonal lake (the seasons on Titan last much longer than Earth's seasons, by virtue of its greater distance from and longer orbit around the Sun).

Aerial views of Huygens' landing site, taken by the probe as it floated down through Titan's atmosphere. Image: ESA/NASA/JPL/University of Arizona.

"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."

For more about the anniversary of the Huygens landing, see the February issue of Astronomy Now, on sale 15 January from newsagents, or available from our online store in print or PDF format. Alternatively you can read the magazine on the Pad or iPhone or Android devices.

• Cassini
• Huygens
• Saturn
• Titan

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Crescent Saturn and Titan seen by Cassini

 

 

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Epic Landing on Saturn's Moon Titan Remembered 10 Years Later

by Mike Wall, Space.com Senior Writer   |   January 14, 2015 03:38pm ET

 

Ten years ago today (Jan. 14), humanity got its first up-close look at a bizarre, frigid moon that may be capable of supporting life as we know it.

The European Space Agency's (ESA) Huygens probe touched down on the surface of Saturn's huge moon Titan on Jan. 14, 2005, three weeks after being deployed from its mothership, NASA's Cassini spacecraft. For the first time ever, an emissary from Earth had landed softly on a world in the outer solar system.

"I distinctly recall the dreamy feeling of being in one universe one moment and in another universe the next," Cassini imaging team leader Carolyn Porco wrote of Huygens' landing in a blog post today. "But it was no dream. We had, without doubt, journeyed to Titan, 10 times farther from the sun than the Earth, and touched it. The solar system suddenly seemed a very much smaller place." [What Huygens Saw on Titan (Video)]

This series of images was taken by the European Space Agency's Huygens probe as it descended to the surface of Saturn's smoggy moon Titan on Jan. 14, 2005.
Credit: ESA/NASA/JPL/University of Arizona

View full size image

Cassini reached the Saturn system in July 2004 and thus had already observed Titan by the time Huygens touched down. But the lander beamed home information impossible to obtain from afar, a data haul that began during Huygens' two-and-a-half-hour descent through the moon's thick atmosphere.

"The images taken by the falling probe and released to the public that night were everything our images from orbit were not: unfiltered, exquisitely detailed views of the moon's surface and unambiguous in their account," Porco wrote.

Those images revealed what appeared to be a shoreline, as well as snaking channels that had obviously been carved by flowing liquid, she added. But that liquid was not water; Titan has a hydrocarbon-based weather system.

The European Space Agency's Huygens lander returned this image from the surface of Saturn's moon Titan on Jan. 14, 2005.
Credit: ESA/NASA/JPL/University of Arizona

View full size image

"It was circumstantial but incontrovertible evidence for the liquid hydrocarbons that we had strained from orbit to find, and thrilling beyond measure," Porco wrote. "It was soon to be followed, after landing, by another unforgettable sight, under a cloudy sky and across a cobble-strewn ground to the moon's horizon in the distance."

Huygens kept sending data to Earth from Titan's freezing surface for 72 minutes before its batteries died and the probe went dark.

The lander's measurements and observations helped lift the veil of mystery that had enshrouded Titan. For example, Huygens took a detailed profile of Titan's nitrogen-dominated atmosphere, gathering temperature, pressure and density readings over a wide range of altitudes.

Furthermore, Huygens' analyses of Titan's atmospheric methane did not support the suggestion that the gas was produced by microbes, ESA officials said. (Most of the methane found in Earth's atmosphere has a biological origin.)

You can read more about Huygens' discoveries here, in a top 10 list ESA compiled to commemorate today's anniversary.

While Huygens ceased operations shortly after touching down on Titan, Cassini has continued to study the huge moon (along with Saturn itself, and many of its other moons). For example, over the course of more than 100 flybys, Cassini has mapped much of Titan's surface and, using radar, probed the depth of some of the moon's biggest hydrocarbon seas. Moreover, gravity measurements by Cassini suggest that Titan harbors a subsurface ocean of liquid water, NASA officials said.

The $3.2 billion Cassini-Huygens mission — a joint effort of NASA, ESA and the Italian Space Agency — launched in 1997. The Cassini spacecraft is scheduled to keep making observations through September 2017, when the orbiter will end its life with an intentional death dive into the ringed planet's thick atmosphere.

 

 

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