VOA慢速英语20060510c

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EXPLORATIONS - Venus Express Spacecraft Explores Earth's Mysterious Sister PlanetBy Mario Ritter and Daniel Kirch

Broadcast: Wednesday, May 10, 2006

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VOICE ONE:

I'm Steve Ember.

VOICE TWO:

And I'm Faith Lapidus with EXPLORATIONS in VOA Special English. Today we tell about a NASA space vehicle orbiting Mars. We also hear what it is like to live in space. But first, we tell about Venus Express, the European Space Agency vehicle.

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Venus is almost the same size as Earth. Its orbit brings it closer to us than any other planet. But its atmosphere remains¹ a mystery. Last month, the European Space Agency successfully deployed² a space vehicle that will study the atmosphere and surface of Venus in greater detail. It is called Venus Express.


An artist's version of Venus Express

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Venus Express carries seven instruments that measure different kinds of electro-magnetic radiation. They include a camera, radar³ and a device that captures space particles. The vehicle started to take some pictures of Venus on April twelfth. These were the first images of Venus's south pole. The spacecraft's final orbit will take it as close as two hundred fifty kilometers above the planet.

VOICE ONE:

The European Space Agency launched Venus Express November ninth from the Baikonur Cosmodrome in Kazakhstan. The agency chose to send a vehicle to Venus to study the planet's mysterious climate. Venus is so much like Earth in size and substance that it is called our sister planet. Yet, its surface is anything but Earth-like. The planet's surface temperature is more than four hundred degrees Celsius⁴.

Scientists want to find out why and how Venus became so hot. Earlier explorations of the planet seem to suggest that there were once oceans on Venus. But those oceans heated up and boiled away.

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The thick atmosphere of Venus now has only very small amounts of gaseous⁵ water and nitrogen. Ninety-seven percent of the atmosphere is carbon dioxide. Carbon dioxide is known as a greenhouse gas because it traps heat. Scientists believe carbon dioxide is one of the causes of the planet's extreme climate.

The atmosphere of Venus holds another mystery. Winds cause the upper layers of atmosphere to travel around the planet at up to three hundred fifty kilometers an hour. That is much faster than Venus rotates. In fact, Venus is the slowest spinning planet in the solar system. It rotates only once every two hundred forty-three Earth days.

Venus Express will measure wind speeds and temperatures at different areas of the planet. Scientists hope the spacecraft will help answer some of the questions about the planet's climate. They also hope that study of the extreme atmosphere will help increase understanding of our own complex climate system.

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Mars, like Venus, is similar to Earth in some ways. Several spacecraft are exploring the fourth planet. The most recent to arrive is the Mars Reconnaissance Orbiter. The American space agency's Orbiter arrived near the planet on March tenth. Last month, the spacecraft took its first pictures to test the abilities of its cameras. The Orbiter carries special cameras that will take pictures useful to scientists studying the atmosphere, surface and geology of Mars.

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NASA says the Orbiter is carrying the most powerful telescopic camera that has ever traveled to another planet. It is called the High Resolution Imaging Science Experiment Camera. It is expected to be able to take pictures showing objects smaller than one meter.


A high-resolution picture from the Mars Reconaissance Orbiter

The camera will take pictures of only one percent of the surface of Mars during the whole project. This is because of the high power and narrow field of the images taken. The Context Camera will take pictures showing more of the surface. And the Mars Color Imager will take pictures of changes in the Martian atmosphere.

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The Orbiter serves several purposes. Many of them are related to the search for water and conditions in which life could exist. Scientists will use the spacecraft to study the surface of Mars in more detail than ever before. And they will search the atmosphere for signs of water and a form of molecular⁶ oxygen called ozone⁷.

Special instruments on the spacecraft are designed to search for evidence of water. The Shallow Subsurface Radar will look a little beneath the surface for signs of ice and possibly liquid water. Cameras will look for evidence of ancient landforms caused by liquid water and possible recent ones.

Another instrument will inspect in detail what minerals are present on Mars. The Compact Reconnaissance Imaging Spectrometer for Mars will analyze⁸ light to look for minerals that may have formed with the help of water.The Orbiter will also provide highly detailed⁹ images of possible places for future spacecraft to land.

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NASA launched the Mars Reconnaissance Orbiter from Cape¹⁰ Canaveral Air Force Station in Florida on August twelfth. The Orbiter is expected to perform experiments and take pictures for two years. But it has not reached its final orbit. By November, it should settle in an almost circular orbit about three hundred kilometers from Mars.

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Many people wonder what life in space is like. But, in many ways, life in space is not too different from life on Earth. Astronauts wear normal clothes, eat almost normal food, sleep every night 鈥?and have fun. Yet, life in space can also be strange when compared to life on solid ground.

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Many people wonder what kind of clothes astronauts wear when they are working in space. At the International Space Station, astronauts wear clothes they would wear on Earth. For example, they wear normal shirts, shorts and pants. But astronauts have to wear these clothes much longer than on Earth.

To save water, there is no washing machine on the Space Station. There also is not enough room to store clothes on the Space Station. So, crews do not change their clothes very often. NASA says crewmembers change their shirts every ten days. They change their underwear every second day. They place old clothes and other waste in a container that falls to Earth and burns up in the atmosphere.

However, astronauts must wear special clothing for launch and landing. Crewmembers on the American Space Shuttle wear Launch and Entry Suits. These suits cover the whole body. They are designed to maintain the right amount of air pressure around the astronaut.

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When astronauts are done with their work, they can decide how to spend the rest of their day. As on Earth, they may want to have fun in their free time. NASA says it is important for astronauts to have fun, especially when they are staying on the International Space Station for a long time. So, scientists who plan the missions try to give astronauts enough free time. Astronauts can watch movies, read books, play games and talk to their families. There are also devices for exercise. Many astronauts simply enjoy looking out of the window.

On the Space Shuttle, astronauts can also look out of the pilot's window to observe the Earth below. Or they can watch the sun rise and set, which takes place every forty-five minutes.

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To do their work carefully, astronauts need enough sleep. They usually sleep for about eight hours. But in space, there is no up and down. Everything is weightless. So, astronauts can sleep in any position. For safety reasons, however, they have to attach themselves to a wall or a seat so they do not float around.

Space Station crews are awakened¹¹ by sound from a clock. But, the crew of a Space Shuttle is traditionally awakened with music. Mission Control Center in Houston, Texas, plays musical requests. The wake-up music can be rock and roll, country, western or classical music.

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Astronauts eat three times a day: in the morning, at noon and in the evening. Food experts plan their diet so the astronauts get a balanced supply of healthy food that includes vitamins and minerals.


Fun with food on the International Space Station

Food scientists at the Space Food System Laboratory at the Johnson Space Center in Houston research and develop special food for space missions. Months before, astronauts can choose what kind of food they would like to eat during their trip. For example they can choose different kinds of fruits, meat and seafood¹². But the foods must be easy to prepare and eat. Astronauts can heat their food in an oven. But there is no way to cool food.

Astronauts also have drinks like coffee and tea. But, some things are very different than they are on Earth. Astronauts cannot use normal salt or pepper because it would float away. So food scientists have developed liquid salt and pepper for use in space.

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VOICE TWO:

This program was written by Daniel Kirch and Mario Ritter who was also the producer. I'm Faith Lapidus.

VOICE ONE:

And I'm Steve Ember. Join us again next week for EXPLORATIONS in VOA Special English.