NASA space missions have been threatened
In recent years the world's space agencies are planning large-scale research missions. All of them require a huge amount of energy carried aboard the spacecraft. And if near the sun still possible to do a solar powered, the long range, this approach does not work and there is an urgent need for high-power energy sources, the main one being nearly over at NASA.
It should be noted that a couple of years ago we wrote about the fact that NASA could suffer the same fate. The fact that on board the spacecraft used radioisotope thermoelectric generator (RTG), derive the energy released by the decay of radioactive isotopes of plutonium-238. Plus the use of radioactive material in that the supply element based on it has no moving parts, it requires no maintenance for decades, and it is enough to feed a small research units. But there are also disadvantages: the production of plutonium-238 is extremely expensive and labor-intensive. In addition, a large part of its global reserves has been developed during the Cold War, during the arms race, and the United States and at all ceased production of plutonium-238 in 1988, began to buy it from Russia.
But existing US stocks came to an end: now NASA has less than 34 kg of plutonium-238. Since it breaks quickly, only about half of it can be used for space missions. Available amount of substance already enough for filling level Cassini mission, which required nearly 22 kg of plutonium-238. Realizing the seriousness of the situation, the United States resumed the production of plutonium-238 a few years ago, but in all that time have received only about 100 grams of the substance. Another 100 grams will be available by the end of the autumn of this year. Thus, according to data provided by the counting chamber, with the production of rare element is not so bright. Ralph Maknutt explained, a leading scientist in the Applied Physics Laboratory of Johns Hopkins University,
"Reactor for production there. He dismantled. Tower cooler demolished in the early 90s. For the production of plutonium-238, Neptunium-237 is used, wherein during the year target bombarded therefrom and a small quantity of plutonium-238. The production itself is still in the experimental phase. "
However, the US space agency remains optimistic. According to one of NASA managers Jim Green,
"I think we're in good shape for the coming decades. We plan to build up stocks of plutonium and do not allow him to limit our future missions. "