The Skeptics Society & Skeptic magazine

THE AMBITIOUS DAWN MISSION, launched in September 2007, is one of NASA’s most remarkable ventures into the solar system. The spacecraft has recently completed a spectacular exploration of Vesta and is now traveling to Ceres; these were among the last uncharted worlds in the inner solar system prior to Dawn. It is the only spacecraft ever to orbit an object in the asteroid belt. Such a mission would be impossible without the use of ion propulsion, a technology that has…