* Astronomy

NASA's Space Shuttle Program conducted the final test firing of a reusable solid rocket motor Feb. 25 in Promontory, Utah. Used on the space shuttle missions, the recyclable solid rocket motor is the largest solid rocket motor ever flown, the only one rated for human flight and the first designed for reuse. Each shuttle launch requires the boost of two reusable solid rocket motors to lift the 4.5-million-pound shuttle vehicle.