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VOICE ONE:
This is Steve Ember.
VOICE TWO:
And this is Doug Johnson with EXPLORATIONS in VOA SpecialEnglish. Today we tell about a new satellite that will be used toexamine the health of Earth’s atmosphere. We report about thousandsof meteors that have already begun to provide a show in the nightsky. We report about beautiful color photographs of the rings thatsurround the Planet Saturn. And we begin with the latest news fromthe two American Space Agency devices that are exploring the planetMars.
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The NASA exploration vehicles on Mars continue to provideinformation about the red planet. The vehicle named Spirit isclimbing an area called the Columbia Hills.
Spirit has already traveled more than three-and-one-halfkilometers across the surface of Mars. This is more than six timesthe distance NASA had planned for Spirit to travel. The increaseddistance has led to some problems with Spirit’s right front wheel.The wheel does not turn as freely as Spirit’s other five wheels.
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NASA scientists who control Spirit have decided to make it travelbackwards on five wheels to rest the problem wheel. The sixth wheelnow will only be used to cross very difficult surface areas.
Joe Melko is a NASA engineer with the Jet Propulsion Laboratoryin Pasadena, California. Mister Melko says using only five wheelswill make Spirit travel much more slowly. However, he says thismethod will permit NASA to continue doing science work with thevehicle much longer than was thought possible.
VOICE ONE:
As Spirit continues to drive upthe Columbia Hills, the exploration vehicle named Opportunity istraveling deeper into a large hole. The hole is called EnduranceCrater. It is in the area of Mars called Meridiani Planum.
Instruments on Opportunity show the element chlorine is presentin the huge hole. Scientists want to know how it got there. Theyalso want to know which elements the chlorine is linked to.
Opportunity will continue on this path to discover more about thechlorine. Scientists also want Opportunity to inspect a row of sharprocks that look like teeth. Scientists believe this unusual area wasformed when liquid moved over the ground.
VOICE TWO:
NASA officials are also preparing the two exploration vehiclesfor the coming of the Martian winter. The middle of winter on Marsis in September. There is less daily sunshine during winter. Thismeans the rovers’ solar cells will be able to collect much lesssunlight to make electric power.
NASA officials say they must plan now for longer rest periods forthe vehicles if they are to keep working through the winter. NASAofficials say the two vehicles will work a little less each day topermit them to collect more sunlight for energy. Or perhaps thevehicles will work every other day while their solar cells produceand store electric power during a longer rest period.
The two Mars rovers, Spirit and Opportunity, landed on the planetin January.
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The Cassini spacecraft has sent back to Earth beautiful colorphotographs of the famous rings of the planet Saturn. Cassini madethe photographs on June twenty-first, a few days before it flew intoorbit around the huge planet.
The photographs show that the famous rings are many differentcolors. They include the color of sand and many shades of brown,gray and pink.
Scientists have color photographs of the rings that were taken inthe past. These include some taken by the Hubble Space Telescope andthe Voyager spacecraft. In the nineteen-eighties, two Voyagerspacecraft flew near Saturn. So did Pioneer Eleven innineteen-seventy-nine.
The photographs sent back to Earth by those spacecraft raisedmany questions for scientists. The questions include: How many ringssurround the planet? What effect do Saturn’s many moons have on therings? The scientists had to wait twenty-five years for a chance toanswer these questions.
The photographs sent to Earth by Cassini are the beginning of afour-year study of Saturn, its rings and its moons. Scientists saymany questions about the planet will be answered soon.
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Scientists say most evidence showsthat the many rings of Saturn are made mostly of water ice. But purewater ice is white. So scientists believe that the many colors ofthe rings are the result of different amounts of other materials.
They say the colors could be caused by small amounts of rock,carbon or other materials. In the near future the scientificinstruments on Cassini will be able to help scientists learn whatthe rings are really made of.
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If you have a computer than can link with the Internet, you toocan see the Cassini photographs of the huge rings. You can also seephotographs of some of Saturn’s moons. The Internet address iswww.nasa.gov/cassini. That Internet address again iswww.nasa.gov/cassini.
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A spacecraft named Aura waslaunched from the Vandenberg Air Force Base in California Julyfifteenth. Aura is NASA’s newest Earth-observing satellite. NASAhopes it will help scientists understand and protect the air webreathe.
Aura was designed to send back information about the quality ofair in our atmosphere. It will also be used to study the changes inEarth’s climate and how weather affects the atmosphere.
The launch of Aura completes the first series of NASA’s EarthObserving System satellites. The other satellites are Terra, whichobserves the land, and Aqua, which observes the water on Earth.
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The new satellite carries four instruments. They are designed tostudy different parts of Earth’s atmosphere. Aura will study theatmosphere from the area where humans live to the stratosphere. Thisis the area where the ozone layer protects life on Earth. Theprotective ozone layer has been damaged in the past. Scientists hopethe new Aura satellite will provide information to help them answerthree important questions. The scientists want to find out if theozone layer is repairing itself. They want to learn the process thatcontrols air quality.And they want to learn how the Earth’s climateis changing. NASA expects the first answers to these questionswithin thirty to ninety days.
The Aura satellite joins a total of twelve other sciencesatellites that have been placed in orbit in the past ten years. Allare now gathering information about the Earth.
Ghassem Asrar is a NASA official for Earth Science. He said thenew Aura satellite will lead to a much better understanding ofEarth. Mister Asrar says it will also help us understand otherplanets in our solar system.
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In the middle of July, Earth entered an area of space that isfilled with very small pieces of rock, ice and other material. Thecomet named Swift-Tuttle is leaving behind this material as itpasses near Earth. Millions of pieces of this material are hittingthe Earth’s atmosphere. When they do, they appear as a quickly drawnline of light moving across the night sky. Each bright line of lightis the material burning up in Earth’s atmosphere.
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The event happens each year and is called the Perseid MeteorShower. It began slowly in the middle of July and will reach fullstrength about the eleventh or twelfth of August.
Bill Cooke is with the NASA Marshall Space Flight Center. He saysthere is something added to the show this year. He says Earth willalso pass through material left behind by the Swift-Tuttle cometlong ago. He says this material was left in space in abouteighteen-sixty-two – during the American Civil War.
Mister Cooke says the Earth will move into this cloud of materialon the night of August eleventh. He says observers in Europe andAsia will see as many as two-hundred of the small lines of lighteach hour if they watch closely. The show will begin at abouttwenty-one-hours Universal Time. This show can only be seen bypeople who live well north of the Equator.
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VOICE TWO:
This program was written by Paul Thompson. It was produced byMario Ritter. This is Doug Johnson.
VOICE ONE:
And this is Steve Ember. Join us again next week for EXPLORATIONSin VOA Special English.