Fission control

摘要

Eight years from now a planetary probe could boost itself out of Earth's orbit, fire up its fission reactors and head off on a nuclear-powered quest for alien life beneath the crust of one of Jupiter's icy moons, Europa. This bold $3 billion mission will be part of NASA's Project Prometheus, a huge effort announced in February that will develop a new generation of nuclear systems for missions to the outer planets. The culmination of Prometheus could even see the first astronauts set foot on Mars. Nuclear propulsion offers obvious advantages over space travel's workman-like chemical rockets. With a plentiful and controllable source of thrust, nuclear propulsion could transform space missions from one-way trips with preset goals into voyages of genuine exploration. Ground control could change the course of a mission on a whim and let craft take unscheduled detours to study planetary features they liked the look of.