Abstract
Technical terms relating to spin dynamics of spacecraft, such as nutation and precession, are differently used in space engineering (especially in the design and operation of satellites) and in classical and celestial dynamics. In some cases, their usage is totally opposite. The difference is thought to come from the difference of viewpoint in defining the dynamic phenomena corresponding to the terms. Many textbooks of space engineering, however, follow the usage in classical dynamics without referring to the generally or traditionally accepted usage by practical space engineers. As an unfortunate consequence, confusion sometimes occurs in real and practical scenes of space activity. In this presentation, the usage and viewpoint of these terms in both space engineering and classical/celestial dynamics are reviewed, and their typical usage is compared for several examples of motion.
