COLUMBIA鈥檚 tragic loss came just two days before NASA delivered its wish list for future missions to its paymasters in Congress. Top of the bill was a spectacular multibillion-dollar nuclear-powered trip to Jupiter, but fixing the shuttle fleet might cost so much that the plan will wither. Like NASA, Congress has been stunned by Columbia鈥檚 loss and may take many months to decide how much cash the agency will get in 2004.
Still, NASA鈥檚 proposals will excite scientists. The Jupiter Icy Moons Orbiter (JIMO) mission would fly sometime after 2010, orbiting, mapping and studying first Callisto, then moving inward to Ganymede and Europa. Goals include mapping organic compounds and subsurface oceans, assessing the possibility of life, and studying the structure and evolution of all three moons.
A small fission reactor that has yet to be developed would provide electricity for JIMO鈥檚 ion-drive propulsion as well as for power-hungry instruments such as radar. For safety, the fissile material would go into space 鈥渃old鈥�, in sub-critical units, on a conventional chemical rocket. It would not go critical until it was a safe distance from Earth.
Advertisement
Such a reactor would be a boon for missions to the outer Solar System, says planetary scientist Mike Drake of the University of Arizona. 鈥淚t鈥檚 not just propulsion. Once you鈥檝e got a lot of power available you can imagine instruments you couldn鈥檛 think of before,鈥� he says.
To fund Project Prometheus, the umbrella name for JIMOand the nuclear engine, NASA is asking Congress for $3 billion between 2004 and 2008. The planetary division of the American Astronomical Society welcomed the Jupiter plan, and also applauded NASA鈥檚 plans for a mission to Pluto and the Kuiper Belt, and continued Mars missions.