The end of the accumulation of nuclear weapons during the Cold War means that the U.S. space agency has enough plutonium for future probes on distant missions, except for a few missions already planned, according to a new study by the National Academy of Sciences United States. Deep space probes past Jupiter can not use solar energy because they are far from the sun. Thus, its energy supply depends on a particular type of plutonium, plutonium-238. This feeds the spacecraft with the energy released during its natural decay. But the plutonium-238 is not found in nature, is a byproduct of engineering arms. United States stopped producing plutonium-238 twenty years ago and since then NASA depended on the supply by the Russians. But now the Russian supply is running out, because Russia has also stopped manufacturing this radioactive material. The Department of Energy United States recently announced that it will restart the program to produce plutonium-238. Jen Stutsman’s spokeswoman says the agency has proposed an amount of thirty million dollars for next year’s budget for preliminary engineering and design. “It’s simple, if you have this specific material, you can not deep-space missions,” said Ralph McNutt, a scientist at Johns Hopkins University, responsible for numerous experiments in deep space missions of NASA. By law, only the Energy Department can produce plutonium-238. Because of this, the NASA administrator, Michael Griffin, has contacted the Secretary of Energy Samuel Bodman expressing the needs of the agency with regard to this material. The National Academy report states that the Energy Department would cost approximately $ 150 million to reach the milestone of eleven pounds of plutonium-238 a year that NASA needs for its spacecraft. Without this material, “a wide range of tasks should be postponed for a long time,” says McNutt. NASA missions that need plutonium-238 include deferred consideration and Mars Science Laboratory, scheduled for launch in 2011, and a mission to visit the outer solar system planets, scheduled for 2020. The last two missions using plutonium were New Horizons probe headed to Pluto, and the Cassini spacecraft sent to explore Saturn. The plutonium-powered probes work for long. The Voyager spacecraft sent beyond our solar system in 1977 could continue operating until 2020, says McNutt. It is true that solar powered sensors are preferable to their nuclear counterparts, since they are cheaper and require simple security measures, says McNutt. But solar-powered probes simply do not work in dark areas of space, including deep craters in the moon. Finally, some complain about the old missions with nuclear energy, as Cassini, the danger of potential accidents. Source: www.msnbc.msn.com
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