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Plutonium-238, which gives approximately polatta energy with one gram and has a half-life of 87 years, is the most effective source of energy available to the spacecraft earthlings. It was from him eat and "Voyagers"which soon will leave the confines of their home Solar, Curiosity, just who took the Martian watch. However, the cold war, the echo of which is a substance that is ended, and the new, fortunately, is not expected.
Once available tens kg, today plutonium-238 was for NASA exotic, radically advanced for the price of gold. (Here and below illustrate NewScientist.)
In 1988 the production of plutonium in the U.S. ceased. Since then, resourceful socienty received it from Russia, and it is on these purchases worked nasevska Galileo and other SPACECRAFT, the objectives of which are outside the earth's orbit.
But in 2009 the Russian side, anxiously stared at reduction of own stocks of plutonium, the production of which not so long ago was also stopped (on the official data), lifted prices above $6 million per kg, which forced NASA, with its limited funding, to say the supply of "sorry, enough".
In 2009, when it happened, NASA was 5 kg of plutonium-238, and it was supposed, that it will be enough until about 2018 - with careful spending. To have its own plutonium need right now to deploy the appropriate program, but then the chances of achieving a stable 2 kg per year by 2018-mu far from absolute. The most unpleasant obstacle to a new plutonium initiative is not the time or the technical complexity and the U.S. Congress. Although the $700 billion military budget to the Congress as a whole agrees (a lot of voters and sponsors working in the military industrial complex), the $100 million that will need (according to the calculations NASA) for the production of plutonium-238, American Parliament NASA will not give. At least so I think in the office. And, we believe, not without reason. Yes, this is one big American military spending, but in this space industry lobbyists hold a candle not suitable representatives of the military-industrial complex.
The situation has three possible exit. The first - place SPACECRAFT exploring Mars, Jupiter and Saturn (and their satellites), on solar batteries. The disadvantages of this solution is that Mars dust storms are able to do away with any device on solar batteries, not to mention the polar regions of the planet, where the solar energy is simply not enough for operation in winter time. On the orbits of Jupiter, Saturn and, for example, Pluto solar constant expected smaller than the earth at 25, 100, and more than 2,000 times respectively. The weight of solar batteries, capable of feeding the probe type New Horizons in the orbit of Pluto, will exceed 99% of the weight of the device, and technically this decision is barbarism.
The second option presented recently NASA-developers for surface cloud of Venus, is to use lithium-carbon dioxide cycle for Stirling engine because solar panels on the surface of Venus atmosphere in 100 times denser than earth's, is also little effect. Only, except Venus, this solution is applicable only on Mars. And that with difficulty: low density of the atmosphere will give rise to the life of the pump to obtain sufficient quantities of carbon dioxide or a Stirling engine will have to do sormalarinin.
Among other things, a new method of obtaining plutonium-238 can be applied for small nuclear reactors that will dramatically simplify the production, today is bound to a few large research reactors.
The third way is still the same plutonium-238. Only this time the specialists of the center of space nuclear research in Idaho falls (Center for Space Nuclear Research, CSNR) proposed NASA to use the cassette and "conveyor" the way of his achievements. Instead of downloading the neptunium-237 for a year in a nuclear reactor, where the neutrons produced plutonium-238, and then extract it using complex chemical processes, it is proposed to organize around the reactor ring with a small receptacles containing neptunium-237. After a few days of capsules can be taken out neptunium-237, 0,01% of which during this time will be the plutonium-238. A new approach to the production of the latter will allow to reduce time of exposure neptunium-237, as well as a variety of unwanted isotopes formed during his prolonged firing of the neurons. This will mean a much more simple and inexpensive process for the chemical treatment of plutonium from impurities and reduce the cost of resume plutonium production up to $50 million
God knows what will prefer NASA. But it is obvious that a delay in this matter very soon, will bring long missions to distant planets of the Solar system.