Effects of space weather studied in communication satellite outages

Space weather could be affecting satellites providing much of the world's access to television, the Internet and global communications, U.S. scientists say. Researchers at the Massachusetts Institute of Technology have been studying the impact of solar flares, geomagnetic storms and other forms of electromagnetic radiation on geostationary satellites, which orbit at the same rate as the Earth's rotation, remaining above the same location throughout their lifetimes in space. Although their sensitive electronics are protected with layers of shielding, over time radiation can penetrate and degrade a satellite's components and performance, they found. "If we can understand how the environment affects these satellites, and we can design to improve the satellites to be more tolerant, then it would be very beneficial not just in cost, but also in efficiency," Whitney Lohmeyer, a graduate student in MIT's Department of Aeronautics and Astronautics, said. The researchers analyzed space weather conditions at the time of 26 failures in eight geostationary satellites over 16 years of operation, and found most of the failures occurred at times of high-energy electron activity during declining phases of the solar cycle. A better understanding of space weather's effects will be particularly important for the next generation of communications satellites, Lohmeyer said. "Users are starting to demand more capabilities," she said. "They want to start video-streaming data, they want to communicate faster with higher data rates. So design is changing -- along with susceptibilities to space weather and radiation that didn't used to exist, but are now becoming a problem." Engineers design satellites with space weather in mind, using radiation models to predict how much exposure a satellite might experience in its lifetime. "But space weather is a lot more dynamic than models predict, and there are many different ways that charged particles can wreak havoc on your satellite's electronics," researcher Kerry Cahor said. "The hard part about satellites is that when something goes wrong, you don't get it back to do analysis and figure out what happened."