TIM FURNISS / LONDON
Bush could announce plans for express mission to Mars within the decade
NASA's 2004 budget request will significantly boost efforts to develop nuclear electric propulsion technology capable of dramatically reducing the time required for spacecraft to reach other planets, including Mars. US president George Bush is expected to seek funding for an initiative, dubbed Project Prometheus, that could result in a mission using nuclear power generation and propulsion being staged before the end of the decade.
NASA has dismissed speculation about a "nuclear rocket", describing Prometheus as an expansion of nuclear electric propulsion work planned under the five-year, $1 billion Nuclear Systems Initiative (NSI) launched last year. The NSI is focused on two areas: radioisotope power system development and nuclear fission electric propulsion and power research. Because of delays in approving NASA's 2003 budget, however, the initiative has yet to get under way.
Nuclear electric propulsion would allow a spacecraft to fly direct to its destination, arriving more quickly, then entering orbit, rather than undertaking long, complex gravity-assisted trajectories culminating in brief fly-bys that characterise current outer planetary exploration missions. The flight time to Mars could be cut by a third, to two months.
Under the NSI, NASA plans to develop multimission radioisotope thermoelectric generators (RTGs) to increase the capability of future orbiters and landers. RTGs use heat from the decay of plutonium to generate electricity. A nuclear-powered Mars rover would carry more instruments and last longer.
RTG development will focus on increasing the power conversion efficiency to reduce launch mass and plutonium use. NASA is considering using a new-generation RTG in the planned Mars 2009 lander.
Nuclear fission power systems generate far more electricity than the 100kW-class RTG, and could drive propulsion systems such as ion engines, Hall thrusters and the variable specific impulse magnetoplasma rocket.
Source: Flight International
