EXPLORATIONS - SPACE DIGEST（在线收听）

EXPLORATIONS - SPACE DIGEST
By Paul Thompson

Broadcast: Wednesday, March 16, 2005

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VOICE ONE:

I'm Faith Lapidus.

VOICE TWO:

And I'm Steve Ember with EXPLORATIONS in VOA Special English. Today we tell about information sent to Earth from the Cassini spacecraft in orbit around Saturn. We report about the two Voyager spacecraft that are now leaving the influence of our solar system.

We tell about the training of the next crew of the Space Shuttle Discovery. And we begin with a report about a newly discovered living organism that had been frozen for many thousands of years.

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VOICE ONE:

 
An image of bacteria found in ancient ice. Living bacteria are stained green.
American space agency scientists have found a new kind of living organism that had been frozen for more than thirty thousand years. NASA scientist Richard Hoover discovered the one-celled bacterium in ice underground near the town of Fox, Alaska. He found the bacterium in an area called the permafrost. Permafrost is a mix of permanently frozen water ice, rock and soil. Permafrost stays at a temperature of about minus four degrees Celsius all the time.

Mister Hoover said he and his team cut into ice that was there during the Pleistocene Age or about thirty thousand years ago.

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Mister Hoover said they found the living bacterium deep inside ice that was about a half meter thick. They removed a piece of the ice and examined it under a microscope. As soon as the ice melted, Mister Hoover says he saw the bacterium begin to swim in the water. Scientists named the bacterium Carnobacterium Pleistocenium. It is very unusual. It does not need oxygen to survive. Mister Hoover and his team said the new bacterium was unknown to science before it was taken from the ice five years ago. It is the first fully described and confirmed kind of organism ever found alive in ancient ice.

VOICE ONE:

The announcement of the discovery of the new bacterium came almost at the same time as a team of European researchers said they found huge blocks of water ice near the surface of Mars. The European scientists said the Martian ice was between two and five million years old.

Mister Hoover says the bacteria he found in the Alaskan ice might be able to survive for many millions of years. And he said this might be true for similar organisms on Mars.

Mister Hoover says scientists now know it is possible for life to exist in extremely difficult conditions. He says studying these kinds of organisms helps us understand the many different kinds of life in the universe.

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VOICE TWO:

 
An artists picture of Voyager One.
In the summer of nineteen seventy-seven, two Voyager spacecraft were launched two weeks apart. Both are now leaving the solar system. However, they continue to make history. In January, the NASA Voyager team observed an anniversary of ten thousand days since the launch of the two spacecraft.

NASA scientists say both spacecraft are working and returning valuable information. Both spacecraft are expected to continue to work and send information back to Earth until at least the year twenty twenty.

VOICE ONE:

NASA scientists say the Voyagers have sent back new information about the effects of the Sun in the far reaches of space. These include effects caused by the movement of atoms through space called solar winds.

Explosions on the surface of the Sun cause solar winds. These explosions release huge amounts of gas into space. An example of information sent back by the Voyager spacecraft includes observations of a huge explosion that took place in April, two thousand three. The effects of that explosion reached Voyager Two in April, two thousand four.

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At the beginning of the flights, three hundred NASA scientists were working on the Voyager program. Today, only ten people are working on the program full time.

Two members of this team have worked on the program since the launch of the Voyagers. Several college students working with the program had not yet been born when the two spacecraft were launched.

During their flight through space, Voyager One and Two flew past Jupiter and Saturn. They provided information that greatly expanded our knowledge of these planets.

Voyager Two went on to fly past Uranus and Neptune. Voyager Two is still the only spacecraft to visit these distant planets. The two spacecraft sent back to Earth almost eighty thousand photographs and huge amounts of information about these planets.

After traveling through space for more than twenty-seven years, Voyager One is now more than fourteen thousand million kilometers from the Sun. Voyager One is the most distant human-made object in the universe. Voyager Two is eleven thousand million kilometers from the Sun.

Both spacecraft are now beginning to leave the solar system. They are studying the area of space called terminal shock. It is where the Sun's influence ends and the dark areas of space begin.

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VOICE ONE:

NASA's Cassini spacecraft continues to orbit Saturn. It is making exciting discoveries almost daily. Cassini has found and photographed a giant hole made by a space object that crashed into the surface of Saturn's moon, Titan.

NASA scientists say the hole is four hundred forty kilometers wide. The scientists say either a comet or an asteroid hit the surface of Titan and created the crater. They say the object that made the crater was from five to ten kilometers in size. The Cassini instruments also made images of another crater. This one was about sixty kilometers wide.

Cassini flew within one thousand five hundred kilometers of Titan's surface. This is the third closest flight Cassini has made near the surface of Titan.

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Just one day after the flight near Titan, Cassini few past Saturn's moon, Enceladus. Cassini sent back the first close images ever seen of this small moon that has the brightest surface in the solar system.

 
The surface of Enceladus.
NASA's Voyager spacecraft had flown by Enceladus in nineteen eighty and nineteen eighty-one. Since that time scientists have been waiting for better images of the moon's unusual surface. Cassini returned images of an icy moon. Some areas of the ice are cracked and broken. Other areas of ice are smooth as glass.

The images show few holes left by the crash of space rocks. Scientists say this usually means an object without such holes is very young. They also say the broken areas of ice might mean Enceladus has some volcanic activity.

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Carolyn Porco is the image team leader for the Cassini project. Miz Porco says Cassini has now observed the surfaces of Titan and Enceladus and the rings of Saturn.

She says Cassini has returned images that are ten times better than those produced by the Voyager flights more than twenty years ago. She says the information sent by Cassini is very exciting.

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VOICE TWO:

For the past several months, a crew of astronauts has been training for the next flight of the Space Shuttle Discovery. They have done most of the training at the Johnson Space Flight Center in Texas.

Recently, the crew flew to the Kennedy Space Center in Florida. They did so to take part in training in the shuttle Discovery on the equipment they will use during their flight.The Discovery flight commander is Eileen Collins. She says the training is extremely important. She says the crew has been training on an exact copy of the Discovery.

However, working on the shuttle Discovery itself is even more important. Experts say training on Discovery is a little like a final test in school before graduation. In this case, graduation is the launch of the Discovery.

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The Shuttle crewmembers already know all the equipment they will use during the flight. But NASA officials say they do not want crewmembers to see the Shuttle Discovery for the first time on the day of the launch. They want them to be at ease with the vehicle.

However, it is not possible for the crew to spend a great deal of time on Discovery. So the test is carefully designed to provide them with the most important requirements. A large group of experts decide what the crew will do during this final test. It takes a great deal of planning.

Flight Commander Eileen Collins says it is time for the United States to get back into space. The Space Shuttle Discovery is expected to be launched into space May fifteenth.

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VOICE TWO:

This program was written by Paul Thompson. It was produced by Mario Ritter. I'm Steve Ember.

VOICE ONE:

And I'm Faith Lapidus. Join us again next week for another EXPLORATIONS program in VOA Special English.