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Magnobraking
Aerobraking works at Mars and is most effective at Venus.
Aerobraking won't work at Mercury as it has a phantom atmosphere. Magnobraking, I speculate another form of braking. Magnobraking would work against the magnetic field of a planet to generate electricity or some other from of resistance to induce orbital trimming. However the effectiveness for magnobraking at Mercury seems dubious because of the weakness of it's field. It's usefulness for electricity next to nil with such an abundance of solar energy there. Yet with the need of four flybys to attain Mercury capture of the MESSENGER mission, could the assistance of less than one thousandth of Earth's magnetic drag be of use for final orbital trimming? Is enough already know about Mercury's magnetic field or need we wait for the results of MESSENGER's mission when the full extent of Mercury's magnetic field, to be able to tell if magnobraking would be useful at Mercury? Jupiter has both atmosphere and magnetic field, most ample for effective aero- and magnobraking. As solar power at Jupiter is feeble, magnobraking would have the added benefit of 'free' electricity. As Jupiter's magnetic fields are well know, could magnobraking be a useful feature for the next Jupiter mission? Now Jupiter has yet another energy resource, it's intense radiation belts. Is there a way to capture energy from these radiation belts? Perhaps by some mechanism similar to the RTG's, radioactive thermal generators already used in space. This could be of much interest for would not such energy be completely free energy? Completely free in contrast to using Jupiter's magnetic fields for free electricity which in the long run over a mission's lifetime would be at the cost of unwanted orbital decay. Your scientifically accurate comments upon these speculations welcome. -- MESSENGER Mission News Mercury's magnetic field (at the surface of the planet) is about 1,000 times weaker than Earth's. The Magnetometer will characterize Mercury's magnetic field in detail from orbit over four Mercurial years -- each 88 Earth days - helping scientists determine the field's exact strength and how that strength varies with position and altitude. This will provide crucial clues to help us determine the internal source of Mercury's magnetic field. ---- |
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Magnobraking
William Elliot wrote in message ...
However the effectiveness for magnobraking at Mercury seems dubious because of the weakness of it's field. It's usefulness for electricity next to nil with such an abundance of solar energy there. Yet with the need of four flybys to attain Mercury capture of the MESSENGER mission, could the assistance of less than one thousandth of Earth's magnetic drag be of use for final orbital trimming? Yes, it's not a big enough effect to bother building into a craft. On the other hand, the thrust from a light sail goes up as the inverse square of the distance from the sun so a light sail equipped craft should be able to navigate into orbit around Mercury though it would take it quite a while to build up enough speed to slingshot around the moon and escape Earth orbit. Also if you are going to operate near Mercury, consider that the Sun has a magnetic field about 100 times stronger than Earth's. -HJC |
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