From: believer@telepath.com Subject: IP: Heavy Leonid meteor shower threatens communications Date: Tue, 06 Oct 1998 06:11:35 -0500 To: believer@telepath.com Source: San Francisco Examiner http://www.examiner.com/981004/1004meteor.shtml Heavy Leonid meteor shower threatens communications Annual light show biggest in 32 years By Keay Davidson EXAMINER SCIENCE WRITER A spectacular meteor storm will ignite the heavens in mid-November, possibly "sandblasting" satellites and threatening everyday services from cell phones to TV shows to data communications. The last great meteor barrage came in 1966, when space satellites were far less common - and far less essential to everyday life. Back then, thousands of meteors per minute shot across the North American sky. Today, the skies are jammed with satellites that aid in weather forecasting, relay data communications and TV signals, and enable military surveillance. The world's satellite network is a juicy target for the blistering celestial rain. Although the meteors are smaller than grains of sand, they travel tremendously fast - more than 40 miles per second, equivalent to a 10-second flight from San Francisco to Los Angeles. As a result, they could knock out or disrupt some satellites' delicate electronics. "This meteoroid storm will be the largest such threat ever experienced by our critical orbiting satellite constellations," William H. Ailor, director of the Center for Orbital and Reentry Debris Studies at the Aerospace Corp. in El Segundo, Los Angeles County, told the House Science Committee on May 21. The 1966 storm appeared over continental North America, but this year's main aerial assault will be visible from Japan, China, the Philippines and other parts of east Asia, and possibly Hawaii. The meteors are debris from a comet, Tempel-Tuttle. Scientists from NASA's Ames Research Center in Mountain View hope to study the shower from aircraft flying out of Okinawa, says Ames principal investigator Peter Jenniskens. They hope to broadcast live TV images of the shower over the World Wide Web. The "Leonid" meteor shower is so named because the meteors appear to emanate from the direction of the constellation Leo. Actually, the shower is a cloud of rocky particles orbiting the sun. Annual event Earth crosses the cloud's path every Nov. 17 and 18. At that time, amateur astronomers enjoy seeing the "Leonids" zip across the sky, sometimes several per minute. But every 30-plus years, our planet crosses a particularly dense part of the Leonid cloud. So the "shower" becomes a "storm," with up to 40 meteors per second and sometimes 50,000 per hour. Although very tiny, the particles move so fast that the friction with Earth's atmosphere will cause them to burn and glow. Visible from hundreds of miles away, they will make the sky look like fireworks. NASA plans to turn the Hubble Space Telescope away from the storm so meteors that hit the giant orbital telescope will miss its super-delicate mirror, says NASA spokesman Don Savage. "NASA is taking (the shower) seriously," Savage said. "We have been assessing what we need to do to ensure our satellites in Earth orbit are going to be operated in a safe manner during this meteor shower." Other satellites might be temporarily re-oriented so that they present the narrowest "cross section" - the smallest target. "We are concerned, and we have been in meetings and making plans concerning the Leonid shower," said U.S. Army Maj. Mike Birmingham, a spokesman for the U.S. Space Command in Colorado, which monitors American military and spy satellites. In his congressional testimony, Ailor said that "because of the very high speed of the particles - they will be moving at speeds of over... 155,000 mph - the storm poses an even greater and somewhat unknown threat." Most particles tiny "Fortunately, most of the particles... are very small, smaller than the diameter of a human hair, and won't survive passage through the Earth's atmosphere," Ailor said. "Our satellites, however, are (in space and) not protected by the atmosphere, so they will be 'sandblasted' by very small particles traveling more than 100 times faster than a bullet. "At these speeds, even a tiny particle can cause damage or electrical problems," Ailor said. "While major holes and physical damage to solar panels and structures are very unlikely, impacts of small particles will create an electrically charged plasma which can induce electrical shorts and failures in sensitive electronic components." Last month, an immense wave of radiation from a neutron star washed over Earth, causing at least two scientific satellites to shut down to protect their electronics. Astronomers said the star, in a constellation about 20,000 light-years away, had unleashed enough energy to power civilization for a billion-billion years. But by the time the radiation found its way across the cosmos and through the atmosphere, it was no stronger than a typical dental X-ray, scientists said. No conflict with space missions The upcoming meteor shower is not expected to conflict with scheduled space missions. The first components of the international space station - a kind of village in space - aren't planned for launch until late November and December, after the shower, Savage said. U.S. Sen. John Glenn, an Ohio Democrat and former astronaut, is scheduled to rocket into orbit on the space shuttle Oct. 29, returning before the Leonid shower. Armed with sensitive monitors, Jenniskens' colleagues will study the meteors' "spectra" - frequencies of light that reveal the particles' chemical composition - through portholes in the roof of a plane. Scientists will also study the particles' effects on atmospheric chemistry, such as the ozone layer that shields us from cancer-causing solar radiation. The scientists hope to measure the particle stream, which may be as dense as one extremely small particle every 10 square meters. If so, then every satellite in the sky may get hit, Jenniskens say. Jenniskens' project - involving some 30 scientists and two aircraft - is funded by NASA, the U.S. Air Force and the National Center for Atmospheric Research in Boulder, Colo. He hopes to transmit high-resolution TV images of the incoming meteors via TV or the Web across a 30-degree field of sky. More information on the project is available on the Internet at www-space.arc.nasa.gov/~leonid/. ----------------------- NOTE: In accordance with Title 17 U.S.C. section 107, this material is distributed without profit or payment to those who have expressed a prior interest in receiving this information for non-profit research and educational purposes only. For more information go to: http://www.law.cornell.edu/uscode/17/107.shtml ----------------------- ********************************************** To subscribe or unsubscribe, email: majordomo@majordomo.pobox.com with the message: (un)subscribe ignition-point email@address ********************************************** www.telepath.com/believer **********************************************