Jun 14 2006
At the very least the planned Martian expedition of 2018 will prove to be five times cheaper if its preparation utilises new technologies developed by Russian scientists. The researchers believe that such considerable savings can be made on transport costs.
The authors' basic premise lies in the reduction of costs on obtaining energy en route and in its more rational use. In other words, the scientists have not only developed a technology that can make light and effective solar batteries in cheaper ways, but they have also found design solutions that enable the use of electric engines for almost the entire journey to Mars and back. Financial support for the scientists comes from the International Science and Technology Centre.
The first thing that the scientists propose to lighten the load, both literally and figuratively, is a new design of solar batteries for space. The researchers attempted to replace crystalline silicon and the even more expensive gallium arsenide with relatively inexpensive amorphous silicon. This replacement foresees a double advantage. Amorphous silicon can be sprayed by the metre onto a substrate ribbon and this is undoubtedly cheaper and technologically simpler than to stick pre-cultivated silicon crystals onto thin substrates.
However by itself amorphous silicon is a poor replacement for the crystalline version. To enhance the performance attributes of batteries made on its basis, the scientists have developed a special technology. Using an ultrafine laser beam and high-precision apparatus for its guidance, the authors learned to create ‘quantum pits' in the initially irregular silicon layer, sections that are 2nm in size with a pre-set atomic structure. Situated in a strict order at a distance of 10nm from one another, these sections create a kind of artificial order in the silicon layer, transforming it into something akin to a genuine crystal. Such a pseudo-crystal in a battery works almost as effectively as a real one and the scientists' forthcoming plans involve the gaining of 15% performance on these batteries.
If the steel substrate of the batteries is made thinner that usual, not 100 microns but 20 (and the researchers have already debugged this technique), the overall weight of the solar batteries will fall accordingly and, proportionately, the costs involved in getting them off the Earth and into space. This is where the savings come from; there is no need to lug superfluous tons of steel and fuel into space.
As a result the scientists calculate that there should be sufficient electrical energy to fly ‘on electricity' and not on liquid fuel. To provide the required speed for the spacecraft, the authors have developed a new version of electric engine that operates not on xenon, a very rare and therefore expensive option, but on krypton or even (potentially) on argon. ‘To date engines of this kind have been used in the main on small satellites and then only to turn the satellite around,' explains one of the project authors, the head of this direction at the Keldysh Research Centre Vitaly Semenov. ‘Xenon is used to create pull in them. This choice is not made by chance either. External electrons in solid atoms of this gas are situated far from the nucleus and, to ‘isolate' them, to transform the gas into ionized plasma, is a relatively simple matter. Then the ready ionized xenon is dispersed in electrical fields and we achieve high speeds of its flow, thanks to which the craft moves in cosmic space.
‘Our solar batteries can "get hold of" sufficient energy in space to ionize cheaper and more accessible inert gases – krypton and argon. Of course this requires considerable energy expense compared with xenon, but the solar batteries and transformers are also specially designed, and they can handle this task.
‘As a result of these and certain other improvements, the costs of a Martian expedition will fall from $100 billion to $16-20 billion. Of course, the precise figures will be determined to a greater degree of accuracy by the project participant countries, and these issues are already of a political kind. As far as the scientific side of the matter is concerned, the preliminary research conducted by our team and our colleagues from the Korolev RSC Energia, Krasnaya Zvezda, IKI RAS and IMBP RAS has proved, at least in the laboratory and partially in orbital experiments, that our technologies do work and that they work very well. Further research is required, but the work done to date enables us to hope for the success both of our developments and for the Mars expedition as a whole.'
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