The Image satellite launched in 2000 to study the Earth's magnetic field has successfully completed its mission. It made observations until last month when engineers discovered that its power supply had failed. Image - short for Imager for Magnetosphere-to-Aural Global Exploration - was the first space probe to study the entire magnetosphere, an invisible field that extends for thousands of miles beyond Earth. During Image's mission, it beamed back dozens of images, including the first global view of a double aurora. The satellite remains in orbit around the sun and does not pose a threat to Earth.