ISSO CALLS ATTENTION TO the use of superconducting magnets in space. With grants from the U. S. Air Force and the NASA-Langley Research Center, UH researchers are proving that superconducting magnets offer a viable technology for meeting the harsh demand of outer-and cryogenic space.

Superconductor magnetic bearing systems have many promising applications. A flywheel kinetic energy storage system incorporating superconductor magnetic bearings can be used for renewable energy storage from fluctuating sources such as the wind. Micro-electro mechanical systems (MEMS) may benefit from levitated bearings since wear is the most serious problem caused by the high surface-to-volume ratio in the micro domain.

Most mechanical devices have bearings as important functional components. Compared to conventional mechanical bearings, the superconductor magnetic bearing is superior in regard to its having an extremely low bearing loss but lacks stiffness to support sizable loads and operates only under cryogenic conditions. Thus, it fits naturally in deep space which is a cold vacuum and away from any significant source of gravity. Conditions on the Moon can provide a cold vacuum.

The extensive presence of dust, which is a problem for conventional mechanical bearings, could also be mitigated by using wide gaps in superconductor magnetic bearings. The demand of extreme precision is met with the almost complete absence of friction in superconductor magnetic bearings. Moreover, the reduced gravity on the surface of the Moon makes the weight of the telescope a manageable load for the superconductor magnetic bearing in spite of its stiffness. Furthermore, we enhance the load-carrying capacity of the superconductor magnetic bearings with additional magnets.

Finally, the passive nature of the superconductor magnetic bearing means that it takes no power to run, as long as it is adequately shaded to keep the superconductors sufficiently cold. This makes it a winner over active magnetic bearings where power is scarce. Research shows that the superconductor magnetic bearing is uniquely suited for telescope mounts on the Moon. It could also be used to advantage in deep space missions.

--Eunjeong Lee

See Superconducting Bearings for Space Telescope Applications