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VOICE ONE:

This is Faith Lapidus

VOICE TWO:

A falsecolor image of Saturn's rings.

And this is Steve Ember withEXPLORATIONS in VOA Special English. Today we tell about NASA'sCassini-Huygens spacecraft that is now in orbit around Saturn. Thespacecraft has already started sending back exciting information andphotographs of Saturn's famous rings and its moon, Titan.

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A pictureof Saturn from Cassini Huygens.

The Cassini-Huygens spacecraftarrived at the planet Saturn on July first. It flew into orbit frombelow the famous rings that circle the planet. Carefully, Cassinicrossed through a large space between two of the huge rings atspeeds close to eighty-seven-thousand kilometers an hour. Cassiniflew to within one-hundred-fifty-eight-thousand kilometers ofSaturn's center. That is the closest Cassini will come to Saturn.

After passing through the rings, Cassini fired its rocketengines. This slowed the spacecraft, permitting it to be captured bySaturn's gravity. In this way, the Cassini spacecraft entered anorbit around Saturn. It had taken Cassini almost seven years toreach Saturn after traveling more than three-thousand-millionkilometers through space.

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It did not take long for Cassini to start making discoveries.Cassini took photographs of Saturn's giant moon Titan in its firstfew days of orbit. These photographs provided details of Titan'ssurface that had never been seen before.

Dennis Matson is a scientist for the InternationalCassini-Huygens project. He says the photographs sent back byCassini are difficult to understand.

He says the photographs do provide the first clear images ofTitan's surface, but will require a great amount of study. Titan hasa thick atmosphere that usually looks almost white in photographstaken with telescopes. However Cassini has special cameras that cansee through the giant moon's atmosphere to study the surface.

Elizabeth Turtle is a scientist with the University of Arizona.She says Cassini's first photographs of Titan's surface have shownunusual features. Mizz Turtle says they do not know what some ofthese features mean. She says it will take a great deal of work tounderstand the surface of Titan.

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Cassini-Huygens carries a total of eighteen scientificinstruments. It used several of these to photograph and make maps ofthe surface of Titan. It also used several instruments to studyminerals and chemicals on the surface of the huge moon.

Kevin Baines is a science team member of the Cassini-Huygensproject. He says Cassini provided evidence of pure water ice in someareas of the surface.

He said it also showed areas of non-ice materials such ashydrocarbons. Mister Baines said the evidence was much differentfrom what scientists had expected. Mister Baines also said Cassinishowed clouds of gas made of methane near the moon's south pole. Hesaid the clouds showed good evidence that Titan has a very activeatmosphere.

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The science team for Cassini says these first images of Titan arejust the beginning. It is only the first information gathered in afour-year study of Saturn and its moons. In the future, the Cassinispacecraft will fly closer to Titan and be able to use radar togather much better details of the moon's surface.

The study of Titan is one of the major goals of theCassini-Huygens flight. Cassini's first trip near Titan was stillmore than three-hundred-thirty-nine thousand kilometers away. Futureplans call for Cassini to make more than seventy orbits aroundSaturn. Forty-five of these will include passing close to Titan.

The closest flight will be only nine-hundred-fifty kilometersaway from the giant moon. This very close flight will permitextremely detailed mapping of the surface.

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Scientists prepare the Huygensprobe.

The Huygens part of the spacecraftwill cut its link to Cassini on December twenty-fourth. It will thenfly down through the atmosphere of Titan to the surface. As itpasses into the atmosphere, it will deploy a large parachute. TheHuygens instrument will send information back to Cassini. Cassiniwill then transmit the information back to Earth.

The Huygens instrument will land on the surface of Titan onJanuary fourteenth, two-thousand-five. It will be the firstscientific instrument to land on the surface of a moon of anotherplanet.

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A realcolor image of Titan.

Saturn's moon, Titan, is verylarge. In fact, it is larger than the planets Mercury and Pluto.Scientists are very interested in Titan because it is the only knownmoon in our solar system to have an atmosphere. It also has largeamounts of nitrogen similar to Earth. And scientists believe it haslarge amounts of carbon material.

This is the same material needed to form life as we know it onEarth. However, scientists are quick to say this does not mean thereis life on Titan.

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The exploration of Titan is exciting for many scientists.Scientists believe evidence found on Titan may help to answer thequestion of how life began on Earth. Most experts agree thisquestion is hard to answer because not enough is known about theatmosphere when Earth was a young planet.

Scientists say they need to know what materials were present atthe beginning of life on Earth. They say some of these answers maybe present on Titan. The carbon material methane on Titan may havebeen easily found on Earth when it was young.

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Cassini carries more scientific instruments and can do morescience work than any spacecraft ever sent to explore a planet. Itcarries twelve science instruments on the Cassini spacecraft and sixmore on the Huygens exploration device.

Cassini is six-point-seven meters high, four meters wide andweighs almost six-thousand kilograms. Electric power for thespacecraft is supplied by thirty-three kilograms of the nuclearfuel, plutonium.

The flight to Saturn represents the work of two-hundred-sixtyscientists from the United States and seventeen European nations.The flight of the Cassini-Huygens spacecraft cost more thanthree-thousand-million dollars.

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The Cassini-Huygens spacecraft is expected to carry out manytasks. There is much to learn about Saturn. First, there are theseven huge rings that circle the planet. They are made of water ice,rock and dust.

Only minutes after it arrived in orbit, Cassini made sixty-onephotographs of the beautiful rings. Cassini's radio sent thepictures to Earth. Radio signals travel at almost the speed oflight. But even at that great speed, it took almost eighty-fiveminutes for the information to arrive on Earth. What scientists sawexcited them.

They saw unusual designs and structures in the rings they hadnever seen before. Cassini's photographs provided evidence that therings are not a solid mass of objects, but many individual linesthat circle the planet. These thin lines are held together and keptin orbit by gravity. Scientists now believe there may be more thanone-thousand different lines or rings that make up the seven greatrings.

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The huge moon Titan is not alone in its orbit around Saturn.Saturn has thirty-one known moons. Thirteen of these moons werediscovered after Cassini was launched on October fifteenth,nineteen-ninety-seven. Scientists want to learn more about how thesemoons affect the rings. New photographs already show that thegravity of the moons has a great effect on the rings. Scientistshope Cassini will provide more information about this in the future.

The Cassini spacecraft is named for astronomer Jean DominiqueCassini. He was born in Italy in the sixteen-hundreds. He laterbecame a French citizen. He made important observations of Saturnand discovered four of its moons. The Huygens exploration device isnamed for Dutch astronomer Christiaan Huygens who also lived duringthe seventeenth century. He discovered the moon Titan.

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If you have a computer that can link to the Internet, you too cansee the photographs of Saturn. You can see the moon Titan and therings that make Saturn such a beautiful planet. Have your computerlink with www.nasa.gov. Then follow the links to Cassini-Huygens.

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This program was written by Paul Thompson. It was produced byMario Ritter. This is Steve Ember.

VOICE ONE:

And this is Faith Lapidus. Join us again next week for anotherEXPLORATIONS program in VOA Special English.