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Probe Lands on Moon of Saturn

A First Glimpse of Smog-Covered Titan

By Guy Gugliotta
Washington Post Staff Writer
Saturday, January 15, 2005; Page A01

DARMSTADT, Germany, Jan. 14 -- Europe's Huygens probe parachuted 789 miles to the surface of Saturn's moon Titan on Friday, ending one of space exploration's most dramatic missions by collecting the first-ever close-up photographs of a bleak, icy world.

One of the black-and-white images, taken from an altitude of 10 miles, showed what appeared to be treacly, glacierlike slush. Another, taken after landing, showed boulders and scree reminiscent of the pictures taken by NASA's Mars rovers last year. A third revealed what looked like mountain crags.


An image of Saturn's moon Titan from the European Space Agency Web site after the Huygens probe beamed data including this image back to Earth through its Cassini mothership, which is orbiting Titan. (European Space Agency Via AP)

_____A Celebrated Landing_____
Huygens Space Probe Video: Space officials' hopes were buoyed after the probe continued to transmit data well past its scheduled landing time.
_____Cassini-Huygens Sites_____
ESA Cassini-Huygens Mission
NASA's Cassini-Huygens site
_____Seeing Saturn_____
Saturn has reached its closest point to Earth and is shining at its brightest with its rings tilted at 23 degrees, an excellent angle for viewing.
_____From The Post_____
On to a Moon of Saturn -- and the Unknown
Summary: Probe Lands on Titan
From Associated Press at 9:38 AM

THE MISSION: The European Space Agency's Huygens probe entered the atmosphere of Saturn's moon Titan in a mission to provide clues to how life arose on Earth.

THE PLAN: The probe carries instruments to explore what Titan's atmosphere is made of and to find out whether it has cold seas of liquid methane and ethane.

THE BACKERS: The mission, a project of NASA, ESA and the Italian space agency, was launched on Oct. 15, 1997, from Cape Canaveral, Fla., to study Saturn, its spectacular rings and many moons.

"I am just delighted," said David Southwood, science chief of the European Space Agency (ESA). "I wanted to know that this [mission] was going to produce unprecedented science, and it has. It's the end of a wonderful day."

Huygens's arrival at Titan, 900 million miles away, marked the longest distance from Earth that a human-made spacecraft has ever traveled to make a landing, and the near-perfect journey put a new exclamation point on the four-year, $3.3 billion mission to explore Saturn, its rings and seven of its 33 known moons.

Titan holds a particular fascination for scientists. Not only is it the only moon in the solar system known to have a significant atmosphere -- about 1 1/2 times as dense as Earth's -- but it is also regarded as "pre-biotic," with characteristics that Earth probably possessed before life evolved.

These include an atmosphere composed mostly of nitrogen and the presence of water, ice and hydrocarbons -- building blocks of life. Because of its 900 million-mile distance from the sun, however, Titan is condemned to be frozen in time.

Until Friday, Titan had frustrated all efforts to get a clear peek at its surface. Methane in the atmosphere reacts in the sun's light to wrap the moon in a permanent blanket of smog -- green at higher altitudes, probably orange on the ground. Huygens was designed to breach this shroud.

The probe smacked into Titan's smoggy atmosphere at 5:13 a.m. EST and used three parachutes in a two-hour, 27-minute trip to the moon's surface, analyzing the atmosphere, measuring the wind and even checking for lightning before transmitting the data to the Cassini mother ship.

Radio telescopes on Earth detected Huygens's data transmissions for more than five hours after touchdown despite Titan's surface temperatures of 290 degrees below zero Fahrenheit, indicating the probe had probably landed on solid ground and not in a hydrocarbon slush or pond, where liquid could have crippled it.

Scientists got the first data from Cassini at 11:18 a.m. EST, and the University of Arizona's Marty Tomasko, head of Huygens's imaging team, displayed the first Titan pictures two hours later. "You see things that look very much like drainage channels," he said of the slushy image, "flowing down to what looks like a shoreline."

This picture suggested that Titan would provide a research bonanza, for it appeared to show that the moon's surface is geologically dynamic, unlike the sterile surface of Earth's moon. "It indicated some fresh activity," said Alphonso V. Diaz, NASA associate administrator for Science. But he cautioned that the "amazing" image will keep "scientists arguing about it for years."

The surface picture presented a forbidding, Mars-like landscape, and Tomasko said the large rocks "may well be ice boulders," hard as stone in Titan's frozen wilderness and eroded by the wind.

"We have a scientific success," announced Jean-Jacques Dordain, director general of the European Space Agency, when the Huygens data reached Earth, triggering prolonged cheers and applause from a packed meeting room. "We are the first visitors to Titan."

In the mission's lone glitch, one of Cassini's two transmission channels appeared to have malfunctioned, but the other -- sending almost all the same information -- worked flawlessly. The data on Titan's wind speed were to move only on the malfunctioning channel, but signals picked up by ground stations effectively duplicated those readings.


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