Satellites and other spacecraft, like most machines, have parts that move against one another. Unlike most machines, however, they operate in extremely cold conditions, their power source is often very limited, and lubricating or repairing them are not exactly easy tasks. It is for these reasons that researchers at Spain’s Universidad Carlos III de Madrid (UC3M) are coordinating the three-year MAGDRIVE project – an international effort to create a mechanical transmission with no touching parts, that doesn’t need any lubrication.
There would be several advantages to such a system. For one thing, conventional lubricants freeze solid at the cryogenic temperatures (around -200C/-328F) of outer space. Then, even if they could stay fluid, there’s the whole question of how to reapply them in space – this is a particularly valid point for unmanned spacecraft. Even when lubricated, interlocking moving components ultimately wear each other down, so fixing the spacecraft also becomes an issue.
Finally, there’s the matter of energy efficiency. According to the UC3M researchers, regular transmissions sacrifice over half of their energy simply overcoming friction. A touchless transmission wouldn’t encounter any friction, so presumably would use very little power.
At this early point in the project, all that is being stated regarding how such a transmission would work is that it would involve magnetism. While the goal of MAGDRIVE is to allow spacecraft to operate for years with no maintenance or repairs, the researchers believe that it could also have applications here on Earth, such as in CT and MRI machines.
Satellites have very different needs than cars and operate under very different conditions as well. If they find the solution for one, it still may not work for the other.
Hydrogen isn\'t \"fuel,\" there are no vast underground pools of the stuff, it has to be manufactured by electrolyzing water or hydrocarbons, both requiring considerably more energy than can be obtained from the resulting refined hydrogen. At best it\'s \"energy storage,\" and not very efficient at that. Hydrogen isn\'t EVER going to be cheap, even if made using sea water and powered by vast arrays of solar panels or wind generators. That may become necessary eventually, but it\'s still erroneous to speak of hydrogen as \"fuel.\"
Methane would be a better fuel choice, as it can be extracted as a waste product of biological processes, or butanol made from agricultural crop residue (that would be bio-butanol), or better still propanol or bio-propanol (same energy content as gasoline but not yet as easily manufactured as butanol).
www.youtube.com/watch?v=s4o7lehAtog
This mechanism switches the optical filter in a beam path in 30 milliseconds, using almost no power and producing almost no vibration. Mechanisms of this nature can be used for many other applications, as well. The goals of the researchers in Spain are quite valid.
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