ESA/NASA
European space officials today displayed the first pictures of the surface of Saturn's largest moon.
ESA/NASA
This image of Titan was taken from an altitude of 16.2 kilometers with a resolution of approximately 40 meters per pixel.
Posted on 01/14/2005 7:16:29 PM PST by neverdem
DARMSTADT, Germany, Jan. 14 - A European spacecraft plunged through the murky atmosphere of Saturn's moon Titan on Friday and successfully came to rest on a bizarre landscape never before explored.
Astronomers expressed joy at achieving the first landing on another planet's moon, particularly Titan, the only moon in the solar system with substantial atmosphere.
"We clearly have a success," said Dr. Jean-Jacques Dordain, director general of the European Space Agency. "This is a fantastic success for Europe."
The first pictures from the spacecraft, Huygens, did nothing to undermine the reputation of Titan as a strange place. One showed what appeared to be deep channels leading to the shoreline of a dark, flat surface, possibly a lake of liquid methane.
"Clearly there is liquid matter flowing on the surface of Titan," said Dr. Martin G. Tomasko of the University of Arizona, an imaging specialist for the mission. That possibility has tantalized scientists, who say Titan may resemble Earth early in its development and could give clues to the origin of life here.
Another picture evoked the rocky landscape of Mars, although astronomers said the boulders were probably ice. The black-and-white pictures, taken as Huygens descended, were a foretaste of more highly processed color pictures that are expected to be made public on Saturday, Dr. Tomasko said.
The photos capped an eventful direct encounter with a mysterious moon. Through the day, officials of the European Space Agency moved from anxiety as the probe approached the Titan atmosphere, to relief when a radio signal hinted that all was well, and finally to elation at the arrival of data analyzing the moon's complex hydrocarbon chemistry and of pictures of the world beneath the enveloping smog.
At 5:13 p.m. local time (11:13 a.m. Eastern time), cheers went up here at the European Space Operations Center as the engineering and scientific data arrived, a seal of mission success.
Although the Huygens spacecraft was part of the $3.2 billion Cassini mission to Saturn in partnership with the United States, the Europeans saw it as a particularly challenging engineering endeavor that could elevate their reputation as major players in space technology. The American-built Cassini spacecraft may have delivered Huygens to the threshold of its achievement, but a spacecraft built in Europe and directed here became the first to land on the moon of another planet.
It is a feat that, as Dr. David Southwood, the space agency's director of science programs, said, is "not likely to be repeated in the lifetime of anyone alive today - so this is a really historic event."
From the early evidence of radio signals and the first data, Huygens entered the dense atmosphere on time, about 11:13 a.m., and on target, with all science instruments gathering observations all the way down. The landing apparently occurred about 1:30 p.m. But the craft's radio signal persisted well after the point when, engineers had predicted, its batteries would die.
Dr. Jean-Pierre Lebreton, the Huygens mission manager, was surprised by the persistence of the signal for more than five hours, the first clear indication that the craft had landed intact. These signals were more like a simple dial tone than a message of scientific data.
The nature of the landing site was not immediately known. But a scientist said that the long-lived radio signal could rule out a touchdown in the lakes of methane and ethane that have been hypothesized, because the craft might have sunk in liquid. So Huygens, scientists said, may have set down on a solid plane of ice or a stretch of gooey tars.
Nor is it clear exactly where the craft touched down. The target was a broad region in the moon's southern hemisphere. An instrument clocking wind speeds, scientists said, may show that the spacecraft was swept off course by dozens of miles.
Preparations for the Cassini mission began in 1981 as a comprehensive exploration of Saturn, known for its beautiful rings and its family of more than 30 satellites, notably Titan, a body larger than the planets Mercury or Pluto. The mission, following up on the tantalizing discoveries of the Voyager spacecraft that flew by for brief looks, is planned to last at least four years, but the plunge into Titan's atmosphere was likely to be its most daring endeavor.
The 700-pound saucer-shaped landing probe was named for the 17th-century Dutch astronomer Christiaan Huygens, who discovered Titan. The seven-ton Cassini carried the smaller craft piggyback over the seven-year journey to become the first spacecraft to orbit Saturn, starting last summer. In December, Cassini released Huygens for the solo cruise of 2.5 million miles to Titan.
For 22 days, Huygens traveled in silence to conserve battery power. Three onboard clocks kept time to enable a programmed command to wake up the craft. Its instruments and communications system were checked out just before entry into Titan's upper atmosphere, about 1,200 miles above the surface.
Meanwhile, the Cassini spacecraft moved into position, more than 40,000 miles away, to receive Huygens's radioed messages of discovery and relay them to tracking antennas on Earth. Cassini then stored the data in four identical copies.
As Huygens entered the atmosphere, its computer set off all the subsequent critical moves. Dr. Claudio Sollazzo, the mission operations manager, said, "Things are supposed to go one after another, like clockwork." And so they apparently did. The reception of the first radio signal by a giant antenna in Green Bank, W.Va., indicated that the spacecraft had entered the atmosphere and continued downward. Subsequent signals reassured flight controllers of a successful landing, through a sequence of parachute releases and the separations of protective covers that exposed science instruments for observations.
The six primary instruments are to measure temperatures, pressures and the composition of the nitrogen-rich atmosphere, with its complex hydrocarbon chemistry, which appears to some scientists to be "prebiotic." But actual life is unlikely to be found on Titan, whose temperature is 292 degrees below zero Fahrenheit.
In October, Cassini's radar and visible-light cameras took pictures of the moon's surface, but dense haze kept scientists puzzled as to whether Huygens would find a landscape of ice, frozen tar or lakes of liquid methane and ethane. Dr. John Zarnecki of the Open University in England said his research team favored a surface of gooey gum on top of ice as the best bet.
The challenge now is for scientists to take the results of one ride through Titan's atmosphere - "this grand descent into the unknown," in Dr. Southwood's words - and pictures of its surface and see if the moon is, as often speculated, a time machine of planetary life. Is its hydrocarbon chemistry indeed similar to conditions that may well have existed on Earth in the early solar system? If so, what does that reveal about the chemistry of the origin of life?
For the time being, the Huygens team put scientific interpretation aside and enjoyed a triumph that was a long time coming.
"You can probably detect a certain relief on my face," Dr. Southwood said, and he was not alone in the control rooms at Darmstadt.
ESA/NASA
European space officials today displayed the first pictures of the surface of Saturn's largest moon.
ESA/NASA
This image of Titan was taken from an altitude of 16.2 kilometers with a resolution of approximately 40 meters per pixel.
Yes.. liquid methane. Just hope it can't send back the smell.
Mercaptans make the smell. Methane is odorless.
ping
You know if a hot object (like a spaceship in inverted rocket landing blast) landed on pure methane, the heat from the vehicle would melt the methane and the vehicle would then become immersed in the liquid methane until it refroze, trapping everyone within.
Tough for humans to land on any planet or moon after Mars.
These are pretty good for one-hour photo processing, but I would dearly like to see something besides rocks. Maybe they are snowballs.
FReepmail me if you want on or off my health and science ping list.
Of course I could put you on my thermodynamics ping list if you wish.
The surface that Huygens is resting on is rock, not frozen methane. I say it's Titan Rover time, in spite of what that Euroweenie says.
Oh, great. Here we go. The Space Cadets will start lobbying for trillions of taxpayer dollars to explore Saturn's moon.
Did I miss remember all that?
Congressman Billybob
Organic in the sense of being a hydrocarbon, but not biologic. You will hear people talking about pre-biological chemistry, but that's another thread.
I like the direction past the mars rover, I've seen research on dragonfly like drones that can fly around mars, observing and reporting back.
Way cool.
Free oxygen shows the presence of life; oxygen is so active that it soon combines with other elements and disappears from the atmosphere unless it's constantly being renewed by further biological activity. Methane I'm not sure about but I think it's just a garden variety chemical.
Not entirely.
"so this is a really historic event."
Indeed it is.
This is the most important historical event of humanity to date, and possible of the 21st century.
An accomplishment of gigantic significance.
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