Solar eruptions scatter high-energy magnetic particles throughout the solar system and can disrupt Earth-orbiting satellites, wreaking havoc on TV transmissions and communications. This fall, NASA plans to launch two satellites that will help astronomers better predict these gigantic events. The satellites, loaded with instruments such as 3-D imagers and particle and magnetic-field detectors, will track Earth’s orbit around the Sun, with one ahead of and the other trailing Earth. Their readings will be combined into a stereo-like view that will enable earlier warnings of solar activity, allowing satellites to power down or go on standby. “It’s like turning off the TV during a lightning storm,” says Michael L. Kaiser, a NASA scientist on the project.