882. Preflight Balance Error Analysis for Dual-Spin Satellites

Paper

Abstract

This paper provides a basic format for preflight balance analysis of the dual-spin satellite the dual-spin satellite, having a roll-to-pitch inertia ratio of less than unity, provides a more stable platform than the pancake-shaped spin-stabilized satellite having an inertia ratio greater than unity. Platform stability varies inversely with dynamic imbalance of the satellite’s spun section. Several balance error sources are discussed and equations are developed solving the satellite imbalance resulting from these errors. By this discussion and development, the analysis attempts to present the logic involved in identifying the satellite imbalance. The analysis does not account for uncertainties in the mass properties of the satellite, but assumes nominal values. Errors that may be caused by aerodynamic effects, thermal effects, or effects resulting from balancing in a one-g field are neglected. A sample problem is presented to demonstrate the use of the equations. The values of the error sources used in the sample problem indicate that a dual-spin satellite would meet a wobble requirement in the arc-second level. These same error sources would produce a wobble angle that is an order of magnitude larger on a spin-stabilized satellite having a roll-to-pitch inertia close to unity.