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EXPLORATIONS -January 16, 2002: Mars1
By Paul Thompson
VOICE ONE:
This is Doug Johnson.
VOICE TWO:
And this is Sarah Long with the VOA Special English program EXPLORATIONS. Today, we
report about the planet Mars. We tell about evidence that weather on Mars is changing. We tell
about plans for a new kind of vehicle to explore Mars. And we tell about the Mars Odyssey2
spacecraft that recently began orbiting the planet.
((THEME))
VOICE ONE:
National Aeronautics3 and Space Administration officials are using the atmosphere of Mars to slow the Mars
Odyssey spacecraft. The slowing of spacecraft also permits it to fly much closer to the planet.
The Two -Thousand -One Mars Odyssey spacecraft arrived at Mars in October. Its early orbit around the planet
was extremely high. The orbit was so high the spacecraft took eighteen and one half-hours to circle the planet.
Today, the Mars Odyssey is much lower and closer to the planet. It now takes only three hours and fifteen
minutes to make one complete orbit of the planet.
VOICE TWO:
David Spencer is the head of the Mars Odyssey project at NASA’s Jet Propulsion
Laboratory in Pasadena, California. Mister Spencer says it will take most of the
month of January to get the Mars Odyssey in exactly the right orbit. He says the two
and one -half-year science mission will begin when the orbit is correct, which should
be in February.
NASA experts have been testing the science instruments on the Mars Odyssey. They
say the instruments are working correctly.
VOICE ONE:
The Mars Odyssey spacecraft was launched in April, Two-Thousand -One. Its main task is to study the surface of
Mars. The surface has long been thought to be a mix of rock, soil and ice material. Odyssey will provide images
that will help scientists identify the minerals that are in the soils and rocks on the surface.
Mars Odyssey also carries instruments that can measure hydrogen in the upper meter of soil. It will search for
evidence of water. It will study the soil and other materials in areas that may be used for future landings.
The spacecraft will also look for radiation risks that could affect any future human explorers. And it will act as a
communications link for future spacecraft that land on Mars.
((MUSIC BRIDGE))
VOICE TWO:
NASA researchers are developing several new devices that will explore the surface of Mars. These devices will
not carry humans. They will carry several different scientific devices and instruments. The devices are called
robots.
Odyssey
NASA researchers hope to design a series of robots that will be able to work together, or work alone on the
surface of Mars. Each robot will look like a small vehicle with four wheels. Researchers hope the robots will be
able to climb very steep areas of the planet surface.
VOICE ONE:
Paul Schenker is the head of the Mechanical and Robotics Technologies Group at NASA’s Jet Propulsion
Laboratory. He is also the chief investigator4 for the robot project. Mister Schenker says the robots will be able to
climb up hills or down into deep valleys to study the surface.
In a recent test in California, two robots helped a third robot safely climb down a side of a hill that dropped
sharply5. These robots were linked together with a long device called a tether. Mister Schenker said the test
showed the robots can work as a true team. They use extremely small computers to share the important
information their instruments gather.
Mister Schenker says the small robots communicate with each other, make informed decisions, and jointly6 work
to control actions. He says you can think of them as one mountain climber with two good friends that help.
VOICE TWO:
In the past year, NASA researchers also successfully developed and demonstrated a single robot that can move
over difficult surface areas. It can move up and over hills that rise sharply.
Researchers say the robot is similar to a small animal. It uses cameras that perform like eyes to look at objects
blocking the way, make decisions and then move over the objects or around them.
The robots could carry many different kinds of instruments. They could be used to search for water or minerals.
These robots are called All Terrain7 Explorer Rovers. They may be part of a future Mars flight. They will be used
to explore the hills, valleys, and hard to reach areas of the Mars.
VOICE ONE:
One of the most unusual devices that may be sent to explore Mars is a large round rubber ball. Researchers hope
to use the winds of Mars to move the large balls across long distances. Researchers have begun calling the balls
“Tumbleweed Rovers.
”
The name comes from a plant that grows in the American southwest. Winds in the desert often tear the
tumbleweed plants loose from the ground and blow them across the sand.
Researchers accidentally discovered the idea of the wind driven ball. They were testing a vehicle that has ball
shaped wheels. One of the wheels came off the device. The wind blew the round wheel across the ground so
quickly that researchers could not catch it.
Researchers who are testing the Tumbleweed Rovers say they will be cheap to produce. Many could be sent to
Mars. The tumbleweed rovers could carry inside them science instruments to seek water. Researches say this
could be another way to find water on Mars.
VOICE TWO:
The use of a robot device to explore the planet Mars is not a new idea. The Mars Pathfinder spacecraft
successfully landed on Mars in July, Nineteen-Ninety-Seven. The Pathfinder carried a small robot called
Sojourner8, named for the American civil rights worker, Sojourner Truth. The little robot outlived its expected
working life by almost twelve days.
It sent back more than five-hundred-fifty pictures as well as more than fifteen chemical tests of rocks and soil. It
also sent back information on winds and other weather information.
The Sojourner rover robot provided the first evidence that suggests that Mars was warmer and wetter at one time
in its past. Researchers are excited about what kind of information future robots will provide when they reach
Mars.
((MUSIC BRIDGE)
)
VOICE ONE:
The planet Mars we know today is a cold, dry, desert-like world. Yet there is some evidence that its climate is
changing. New observations by NASA’s Mars Global Surveyor spacecraft are expanding our understanding of
the Martian climate.
NASA scientists say new evidence suggests large climate changes have taken place during the planet’s recent
history. They say even larger changes may take place in its future. They say it is possible Mars may become
warmer and wetter as some scientists say it was in its early history.
The scientists say the climate evidence was gathered during one Martian year. One Martian year is equal to six
-
hundred-eighty-seven Earth days.
VOICE TWO:
Pictures from Global Surveyor’s camera system show that holes in the surface of the ice at the southern pole of
Mars have increased greatly in size in the past year. NASA scientists say this shows that heat below the surface
has caused material to change from frozen9 liquid into gas, which escapes into the atmosphere.
Michael Malin is chief investigator for the Global Surveyor’s camera system at Malin Space Science systems in
San Diego, California. He says the frozen liquid may be carbon dioxide ice.
Mister Malin says changes in atmospheric10 pressure could be linked to the increased size of the holes in the ice at
the Martian south pole. He said if this is true, it is more likely that water was present as a liquid near the surface.
The presence of liquid water on Mars would make it more likely life may once have existed on the planet.
VOICE ONE:
James Garvin is NASA’s top scientist for Mars Exploration. He says that finding evidence of climate change on
Mars is important information.
Mister Garvin says information gathered by the Mars Global Surveyor will tell where landings of other spacecraft
should be made in the next ten years. He said the information shows that polar areas should be good places to
search for evidence of hot water produced deep below the surface of Mars.
Experts say the Global Surveyor is continuing to provide important information that helps in understanding
Martian climate of the past. And they say the spacecraft is continuing to provide information about what might
happen to the climate of the planet Mars in the future.
((THEME)
)
VOICE TWO:
This Special English program was written by Paul Thompson. Our director was Cynthia Kirk. Our studio
engineer was Mick Shaw. This is Sarah Long.
VOICE ONE:
And this is Doug Johnson. Join us again next week for another EXPLORATIONS program on the Voice of
America.
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收听单词发音 |
1
Mars
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| n.火星，战争 | |
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odyssey
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| n.长途冒险旅行；一连串的冒险 | |
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aeronautics
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| n.航空术，航空学 | |
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investigator
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| n.研究者，调查者，审查者 | |
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sharply
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| adj.锐利地，急速；adv.严厉地，鲜明地 | |
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jointly
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| ad.联合地，共同地 | |
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terrain
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| n.地面，地形，地图 | |
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sojourner
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| n.旅居者，寄居者 | |
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9
frozen
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| adj.冻结的，冰冻的 | |
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atmospheric
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| adj.大气的，空气的；大气层的；大气所引起的 | |
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