EXPLORATIONS #1905 - Digest

By Paul ThompsonThis is Shirley Griffith.And this is Steve Ember with the VOA Special English program EXPLORATIONS. Today we will tell about new evidence that suggests water may be present on the planet Mars. We tell about two different plans being studied for NASA's next space vehicle that will be sent to explore Mars. We tell about rocket technology that will reduce travel time to Mars. And, we tell about devices to collect information that may be used to search for evidence of life on other planets.

()The United States Space Agency, NASA, says it has new information suggesting that water exists on the planet Mars. NASA says its Mars Global Surveyor satellite has provided pictures that show what may be the effects of moving water. The pictures returned by the Mars Global Surveyor satellite are the most detailed pictures yet taken of Mars.

Michael Malin (pron:"May'-linn) is the chief researcher for the Mars Orbiter Camera on the spacecraft. He says the camera shows ground that appears to have been shaped recently by moving water. He says the pictures show soil and rocks that look like they have been moved by water. He says the formations are very similar to the damage left behind by a sudden flood here on Earth.

Mr. Malin says researchers are seeing evidence of a ground water supply in some of the coldest places on the planet. He says these new formations have not been seen before on Mars.Scientists have believed for many years that huge amounts of water were present on Mars millions of years ago. They believe the planet was warmer and wetter in its ancient history.

Ken Edgett (pron: Edge'-it) is a researcher who works with the Mars Global Surveyor spacecraft. He says the new pictures help explain what happened to the water. He says some of that water went under the surface of the ground. He says it is very possible the liquid water is still there.

All experts say the discovery of water is extremely important to future exploration of Mars. Space scientists say liquid water could be used by future human explorers who travel to the planet. Water could be used for survival and to help make fuel energy to be used by a spacecraft's rocket motors.Scientists are also extremely interested in water on Mars because it may hold some kind of bacteria. Bacteria can live in severe conditions here on Earth. For example, bacteria can be found in extremely hot water near volcanoes. Bacteria are also found in the extremely cold waters of the Arctic and Antarctic.

NASA scientists say their research teams will continue to use the Mars Global Surveyor spacecraft to search for more evidence of water on Mars.

(((MUSIC BRIDGE)))The discovery of evidence that suggests water on Mars could be extremely important to the next planned spacecraft flight to Mars. In Two-Thousand-Three, NASA will launch a new space vehicle to Mars.

NASA says it is deciding between two different proposed devices. One is a spacecraft that will orbit Mars. The other is a large scientific vehicle that will land on Mars.

The two designs were chosen from many different ideas that were being studied. Two separate teams are working on the two different projects. One team is working at the NASA's Jet Propulsion Laboratory in Pasadena, California. The other team is working at Lockheed Martin Astronautics in Denver, Colorado. Both teams are investigating the danger, cost and readiness for flight of each project. NASA is proposing thirty-six months of development leading to a launch of the spacecraft in May of Two-Thousand-
Three.The two space vehicles are very different. The first is called the Mars Surveyor Orbiter and would be placed in a high orbit around Mars. It would use several different scientific instruments to further study Mars.

It would also carry new, powerful color cameras to take extremely close pictures of the planet's surface. And it would carry communications equipment that could be used for the next ten years to support more space flights to Mars.

The other design being considered includes a space vehicle that would land on Mars. It is called the Mars Mobile Lander. The device would be similar to the successful Mars Pathfinder spacecraft that landed on Mars in Nineteen-Ninety-Seven.

However, Mars Mobile Lander would leave its landing device and travel around the surface of Mars for as long as thirty-days. It should be able to travel as much as one-hundred meters each day.

The Mars Mobile Lander would search for minerals and for evidence of water and materials linked to water. It would study rocks and sand. It will carry its own communications equipment to send information back to Earth.Ed Weiler is the Associate Administrator for Space Science at NASA headquarters in Washington D-C. Mr. Weiler's job will be to choose which of the two designs has the best chance for success. He says the final decision will be made early next month.

Mr. Weiler says NASA's budget will only support one of the proposals. He says it will be extremely difficult to choose one.

(((MUSIC BRIDGE)))Future flights to Mars will one day call for human astronauts to fly to the planet. They may be able to make the trip in about half as much time as the trip now takes if a new rocket motor is successful.

A company, M-S-E Technology Applications, has signed an agreement with NASA's Johnson Space Center in Houston, Texas to produce such an engine.

The rocket is called the Variable Specific Impulse Magnetoplasma Rocket. Johnson's Advanced Space Propulsion Laboratory is developing the technology. The head of the project is NASA astronaut Franklin Chang-Diaz.The new rocket uses plasma, sometimes called the fourth state of matter. Stars are made of plasma. It is a gas made up of atoms with reduced amounts of electrons. The gas is heated to extreme temperatures -- millions of degrees. This heated gas provides the power.

On a trip to Mars, the rocket would continue to increase in speed until it reached about half the distance to the planet. Then the engine would be used to slow the spacecraft. Mr. Chang-Diaz says the flight would take a little more than three months. A flight using the technology of today would take between seven and eight months.

(((MUSIC BRIDGE)))NASA scientists are planting small devices in gardens to test how they collect and transmit information. The small devices would be used to search for biological activity on planets.

Many of the small devices would be spread over a large area. They collect evidence of gases produced by bacteria or microorganisms living beneath the surface of a planet.The devices are called sensors. Kevin Delin is leader of the Sensor Webs Project at NASA's Jet Propulsion Laboratory, in Pasadena, California. Mr. Delin says a sensor web is a number of small devices that are all linked together with radio communications equipment. They collect and share information about the environment. The collected information is then sent to a command device. The information is then transmitted from the command device to the Internet or to a satellite in orbit.

Mr. Delin says the sensor webs offer a means to make extremely accurate biological measurements over large areas. He says the devices are easily replaced if one fails. The failure of one device will not affect others in the area because they are linked by radio and not by wire.Mr. Delin says several sensor webs can be placed in a large area. He says these devices will work together. On Earth, sensor webs could be dropped from an airplane on Earth. They could be dropped by spacecraft on other planets. Or they could be released and left behind by a device that travels around the surface of a planet.The sensor webs are now being tested on Earth. They have been placed in the gardens of the Huntington Library, Art Collections and Botanical Gardens, in San Marino, California. There are about fifteen-thousand different kinds of plants from all over the world in the Huntington gardens.

Mr. Delin says the Huntington Gardens are a perfect place to test the sensor web devices. The gardens provide an unusual environment. They include areas that lack water like a desert as well as areas that are warm and wet. The tests of the sensor web devices in different climates will help NASA scientists prepare for studying biological activity on planets.

()This program was written and produced by Paul Thompson. Our studio engineer was Efim Drucker. This is Shirley Griffith.And this is Steve Ember. Join us again next week for another EXPLORATIONS program, in Special English on the Voice of America.

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