2004-2-3
(THEME)
VOICE ONE:
This is Shirley Griffith.
VOICE TWO:
And this is Steve Ember with
EXPLORATIONS in VOA Special English. Today we complete our two
programs about exploring the planet Mars. We tell about the two
vehicles that have landed successfully on the Red Planet and are
exploring the surface for evidence of water and life.
(THEME)
VOICE ONE:
People on Earth have always been interested in the planet Mars.
Recently, that interest has increased because several successful
spacecraft have been placed in orbit around Mars. These include the
American space agency's Mars Global Surveyor and Mars Odyssey and
the European Space Agency's Mars Express.
Each of these spacecraft has increased our knowledge of Mars.
Each has sent back huge amounts of scientific information and
photographs of the planet. The National Aeronautics and Space
Administration has given that information and photographs to the
public on the Internet computer system. This too has increased
public interest in Mars.
VOICE TWO:
Perhaps the most exciting event took place on January third. That
is when the first of two Mars exploration vehicles successfully
landed on the Red Planet. The first lander is named "Spirit." It
came to rest in an area of Mars named Gusev Crater. Millions of
people used their computers to link with NASA's Internet Web site to
see photographs sent back by Spirit.
VOICE ONE:
On January fifteenth, NASA scientists told Spirit to use its six
wheels to move off the landing device. It did this successfully and
rolled on to the surface of Mars. Excited NASA officials said Spirit
was now ready to begin its task of exploring the surface of the Red
Planet.
Scientists on Earth sent commands
to have Spirit move to a rock that could be clearly seen in
photographs. It did this successfully. Spirit continued to send back
photographs and valuable information.
On January twentieth, scientists told the exploration rover to
use one of its tools to study the soil near the rock. The next day,
Spirit began having problems. It answered radio signals, but it
would not send back scientific information.
NASA officials began to work to correct the problem with Spirit's
computer. The part of the computer that stores information was not
working correctly. On February first, NASA announced that Spirit's
computer memory had been successfully repaired. It will begin
scientific examinations of rocks later this week.
(MUSIC)
VOICE TWO:
On January twenty-fourth, the second rover device reached the
surface of Mars. It too immediately began sending back photographs
of a very different area of Mars. Public interest in Mars increased
again.
The second vehicle is named "Opportunity." It landed in an area
of Mars called Meridiani Planum. NASA scientists say Opportunity
landed inside a large hole in the surface of the planet.
Photographs from Opportunity show several large formations of
rock. The photographs clearly show this rock is below the surface.
NASA scientists say the rock they see in the photographs is not like
anything they have ever seen before.
On January thirty-first, Opportunity moved off its landing device
and on to the surface of Mars. NASA officials say it will examine
soil in front of it for the next several days.
Steve Squyres is a scientist at
Cornell University in Ithaca, New York. He is the chief investigator
for science instruments on both Opportunity and Spirit. He says the
areas where the two devices landed are very different. He says
Opportunity landed in a very strange and wonderful area for
scientific investigation.
He says that scientists are extremely excited about the Meridiani
Planum area. Mister Squyres says it is good that Opportunity landed
in a hole. It will be able to explore areas below the surface of the
planet without having to dig.
He also says the hole is not deep. This means when Opportunity is
done exploring this important area it will be able to drive out of
the hole with little or no problems. It will then be free to explore
other areas.
VOICE ONE:
NASA officials say they have discovered and confirmed that
Opportunity landed on an area of Mars that is rich in the mineral
crystalline hematite. On Earth such hematite usually forms in the
presence of water. Scientists want to know if the hematite on Mars
was formed under water too.
Some evidence suggests that long ago the Meridiani Planum area of
Mars was wet and held water. Opportunity will search for more
evidence of water and any evidence that some kind of life could have
existed in the area.
The Meridiani Planum where Opportunity landed and Gusev Crater
where Spirit came to rest are very different. They were both
carefully chosen from among one-hundred-fifty areas on Mars.
NASA officials were able to make the choice using photographs and
information supplied by the Mars Global Surveyor and Mars Odyssey
spacecraft. Both are in orbit around the planet.
(MUSIC)
VOICE TWO:
The Spirit and Opportunity exploration vehicles carry special
scientific equipment to learn many of the secrets of Mars. Both
vehicles are exactly the same. Each weighs one-hundred-seventy-four
kilograms. Each carries several cameras. But the cameras are used
for different purposes.
One camera is used to see where the vehicle is going. It searches
for a clear path that is free of major objects.
Another camera takes extremely detailed color photographs. It can
take photographs in a complete circle around the exploration
vehicle. One camera is inside a microscope that can see objects as
small as a human hair.
Batteries provide power for the exploration rovers. The batteries
store power they receive from special solar collectors that change
sunlight into electric energy.
VOICE ONE:
The exploration rovers carry communications equipment that
permits them to communicate directly with Earth. They can also
communicate with the Mars Global Surveyor satellite in orbit around
the planet. The Surveyor satellite can pass on information it
receives from the rovers.
Each rover carries a special computer that can survive in the
extremely cold temperature of Mars. The computers can also survive
extreme amounts of radiation.
VOICE TWO:
The rovers each carry a science instrument called the Alpha
Particle X-Ray Spectrometer. This instrument can be placed on rocks
and soil to study the chemicals inside.
Another tool is called the Thermal Emissions Spectrometer. This
tool studies minerals in rocks and soil from a distance by measuring
the amount of heat radiation they release. It can also study the
planet's atmosphere.
Devices called Capture-Filter Magnets can capture and hold dust
that contains small amounts of iron. The other scientific
instruments can then study this dust.
One of those instruments is the Mossbauer Spectrometer. This
instrument is designed to study minerals that have large amounts of
iron.
Spirit and Opportunity each carry a Rock Abrasion Tool. This is a
powerful machine that uses electric motors to grind away the surface
of rocks so the inside material can be inspected and studied. This
is done with the microscope camera and other scientific instruments.
VOICE ONE:
Mister Squyres says all of the science instruments make the two
vehicles into mechanical scientists. He says they use their color
cameras and infrared instruments to study rocks and interesting soil
at a distance. The vehicles then are commanded to go to the rocks or
areas of soil that seem most interesting.
When they get to an interesting area they reach out with a
mechanical arm that carries several tools. The arm carries the
microscope, two instruments for identifying what the rock is made of
and a tool for cutting into the rock.
Scientists say that Spirit and Opportunity will explore the
surface of Mars for as long as ninety days. The rovers will be
exploring the surface in an effort to find evidence of water on
Mars. Water is extremely important to any future human exploration
of Mars.
The two devices are trying to discover if we have not been alone
in the universe. They are trying to answer the question: Is there
any evidence that life once existed on the Red Planet?
(THEME)
VOICE TWO:
This Special English program was written by Paul Thompson. It was
produced by Mario Ritter. This is Steve Ember.
VOICE ONE:
And this is Shirley Griffith. Join us again next week for another
EXPLORATIONS program on the VOICE OF AMERICA.