Magnetostrictive Filter-Wheel Drive

The figure shows a prototype of a magnetostrictively actuated mechanism that would rotate an optical filter wheel for a high-performance infrared camera or telescope. Typically, a high-performance infrared instrument and its filter wheel are operated inside a cryogenic system. In conventional practice, the filter wheel is turned by use of a stepping motor in a warmer location. The mechanical connection between the stepping motor and the filter wheel is designed to be as thermally isolating as possible, but it still leaks appreciable heat into the cryogenic system. In contrast, the magnetostrictive drive can be operated with minimal heat leakage because it can be mounted inside the cryogenic system along with the filter wheel and infrared instrument. Moreover, in comparison with a stepping-motor drive, the magnetostrictive drive is simpler, less expensive, and more reliable.