Some dynamical design considerations for momentum biased spacecraft

This paper discusses some of the dynamical aspects that affect the attitude behavior of a spacecraft placed in a near earth polar orbit. The parameters such as atmospheric density variation, super-rotation of upper atmosphere, pitch equilibrium angle, and trim boom length selection to reduce pitch axis drift are considered. These parameters are studied with reference to two momentum biased satellities (Magsat and Dynamics Explorer-2) and the analyses are correlated with observed flight data. It is found that the design model of certain parameters has to be improved by including other phenomena so that flight data and the analytical model predictions have good correlations. The effects of mass imbalance on the orbital and nutational modes of the spacecraft attitude are discussed.