Abstract: A system and method correct crystal pulling motor speed deviations in a crystal pulling mechanism. In a first embodiment, a processor implements a tracking filter by estimating new filter state based on previous state and the since-then-travelled nominal distance, and then updating the filter state based on estimation error and filter gains which are also functions of the travelled nominal distance. In a second embodiment, a harmonic tracking filter suppresses residual harmonic modulation and allows a short time constant. Rapid variations of pulling speed may thus be corrected.

Abstract: A vehicle includes at least one polyoxymethylene structural support member. The polyoxymethylene structural support member includes a polyoxymethylene component that is a propellant that provides thrust to the vehicle upon pyrolysis or combustion of the polyoxymethylene component of the product of pyrolysis of the polyoxymethylene component. The vehicle can be a satellite or other type of spacecraft.