Nov. 10, 1999 To keep their satellites operating smoothly, NASA, the U.S. Air Force and the University of Western Ontario in London, Ontario, will soon open and operate the first center for monitoring the annual Leonids meteor shower around the clock.
In a separate effort to learn more about these dazzling fireballs, NASA scientists will launch a balloon to record meteor images and sounds -- and maybe even catch a piece of a "shooting star."
A Leonids shower happens every year when Earth passes close to the orbit of the comet Tempel-Tuttle and the debris left in the comet’s path. As Earth travels through the comet dust, the debris burns up in Earth’s atmosphere, and observers typically see about 10 to 20 shooting stars an hour. But some experts predict this year’s annual shower may turn into a "storm" -- a spectacular display of 1,000 meteors per hour or more.
To monitor any increases in meteor activity, the Leonid Environment Operations Center at NASA’s Marshall Space Flight Center in Huntsville, Ala., will be staffed 24-hours a day from the afternoon of Nov. 15 until the shower has passed on Nov. 19.
Marshall Center engineers will coordinate and distribute pre-Leonid storm information and real-time observations about Leonid activity, intensity and potential threat to NASA and U.S. Air Force spacecraft. A worldwide network of radar and optical observation sites sponsored by the Air Force and operated by the University of Western Ontario will send information to the Leonid Environment Operations Center at Marshall, where scientists and engineers will analyze the information and distribute it to satellite operators.
"NASA, the Air Force, the University of Western Ontario and several other organizations have teamed together to provide these space weather updates to keep spacecraft operators well informed so they can best protect our satellites," said Dr. Jeff Anderson of the Marshall Center’s Engineering Directorate. "Monitoring the Leonid meteor stream also provides a rare look at a natural phenomenon that will continue to grow in importance as more and more satellites orbit our planet, and we venture deeper into space."
Although a typical meteor is smaller than a grain of sand, it travels more than 40 times the speed of a bullet. The Leonids are the fastest of all the meteor streams, fast enough to circle the globe in less than 10 minutes. Meteor impacts can impair satellites and their sensitive sensors.
Space weather forecasts are not something one hears on the nightly news because they are tricky at best. Will this year’s annual Leonids display be just a shower -- a few to a few hundred shooting stars per hour? Or will it be a storm -- a few thousand to a few hundred thousand meteors an hour?
"In 1998, the world watched and nothing happened," said Anderson. "But in 1966, most folks in the western U.S. were sleeping while one of the most spectacular displays in history was going on over their heads."
It is because many experts are predicting a storm this year that the Marshall Leonid Operations Center is being staffed around the clock during the shower. Just last year, the comet Tempel-Tuttle visited our inner solar system, depositing a dense cloud of debris.
But because Earth crossed the comet’s orbit too soon after the comet’s passage, there was no storm -- just a strong shower.
In 1999, the Earth will pass only 68,200 miles (110,000 kilometers) from the comet debris cloud, making a storm more likely.
In another activity, Marshall scientists will work to give the public a clearer view of the streaking fireballs. Weather permitting, they will launch a 10-foot (3-meter) diameter weather balloon from Marshall’s Atmospheric Research Facility at approximately 12:30 a.m. CST, early Thursday morning Nov. 18.
The balloon will ascend approximately 20 miles (32 kilometers), carrying a sensitive camera for capturing pictures of the meteors. During the flight from around 12:30 a.m. to 3:30 a.m. CST, both still and low-resolution television from the onboard camera can be viewed online at the Science Directorate’s Web site at http://www.leonidslive.com.
Last year, more than one million people tuned into the live Web cast or saw the replay the next day on the Web site. This year a new feature will be a recording device that sends back sounds of meteors from space. Visitors to the Web site will be able to hear the "whistlers" and other bizarre noises that meteors make as they interact with ionized gas or plasma in the Earth’s atmosphere. Scientists hope to use this radio receiver to record very low frequency electromagnetic emissions below 10 kHz emitted by the meteors.
A capture device on the balloon may even bring back a meteor particle. Scientists are still analyzing data from an aerogel-collecting device that was flown last year to capture bits of comet Tempel-Tuttle. The meteoroid capture device on the upcoming flight uses xerogel, a close relative of aerogel, and a variety of low-density acrylic materials.
"It works like flypaper," said Dr. John Horack, an astronomer at the Marshall Center. "We expose these materials to the air up in the stratosphere while the meteor shower is under way. When tiny particles strike the exposed xerogel, they stick."
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The above story is based on materials provided by NASA Marshall Space Flight Center.
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