AEROSPACE

While weather likely has been a common topic of conversation since ancient humans first learned to articulate their thoughts millennia ago, one of the hottest topics today among scientists is space weather. The violence of space weather, changes in the web of magnetic fields and energetic particles that originate from the sun and disrupt the near-Earth environment, is well documented, said University of Colorado at Boulder scientist Daniel Baker. Events range from coronal mass ejections shooting hundreds of thousands of miles into space to million-mile-per-hour winds blowing charged particles toward Earth, at times disabling satellites and major power grids. Technological challenges to damaging space weather events are growing as a "cyberelectric" cocoon weaves more tightly around Earth. But the ability of researchers to predict such events and mitigate negative effects to spacecraft, ground-based power facilities and air and space travelers is becoming a more attainable goal, Baker said. "The region of space between the sun and Earth is a very hostile environment, and we must be vigilant," he said. "With new observations, numerical simulations and predictive models, scientists now are making progress toward dealing with space weather." Baker authored a perspective article in the Aug.30 issue of the prestigious weekly journal, Science, titled "How to Cope with Space Weather." "We are seeing our satellite and communication systems becoming more susceptible to damage by space weather, and the risk is growing," said Baker, director of CU-Boulder's Laboratory for Atmospheric and Space Physics. But he noted the first major line of defense by humans against severe solar storms and their consequences -- robust satellites and systems -- has largely been met. "A new NASA initiative, "Living With a Star," aims to observe systematically the solar disturbances and follow these space weather drivers to their ultimate dissipation in Earth's atmosphere," Baker wrote in Science. The space weather issue also resulted in the 2002 formation of a $20 million, multi-institutional center to create computer models of potentially damaging space weather events and to devise new methods of protection, he said. Known as the Center for Integrated Space Weather Modeling, the center is led by Boston University and involves seven other universities, including CU-Boulder. The new consortium also involves five other participating institutions, including Boulder's National Center for Atmospheric Research, the National Oceanographic and Atmospheric Administration's Space Environment Center in Boulder, the Space Science Institute in Boulder and Lockheed Martin Corp. of Denver. The challenges faced by consortium scientists and other researchers are formidable, Baker said. "During a coronal mass ejection, clouds of charged gases weighing 10 billion tons or more may spew toward Earth at speeds of one million to two million miles per hour." High-energy electrons produced in Earth's magnetosphere by the cloud can penetrate the region of space containing orbiting spacecraft, embedding themselves in insulators and building up electrical charges similar to static electricity that result in miniature bolts of lightning shorting out electrical systems, he said. Aerospace engineers also are working on developing new materials -- including glass composites -- to prevent the build-up of electrical charges on the exterior and interior of satellites. "We don't like to see these electrical charges build up inside or on the surface of spacecraft, because it often results in damage," said Baker. In 1997, a $200 million AT&T communications satellite was destroyed during a solar storm. Such charged-particle events also affect Earth's surface. In 1989 a major storm caused powerful electrical currents in a large power grid in the Hydro Quebec power system, shutting down the system for eight hours as transformers burned out and causing a domino effect further along the grid. The Quebec incident very nearly spread to grids in the northeast United States, but was halted by the disconnection of several grids by engineers, he said. "By developing more specific space weather forecasts and characterizing the potential hazards to spacecraft and communications systems, the better our societies will be able to cope," said Baker. "Ideally, we would like to be able to make more accurate forecasts of impending space weather events expected to impact Earth with lead times of days or weeks rather than hours."