Modeling and Control Design for a New Spacecraft Concept for Measuring Particles and Fields with Unprecedented Resolution and Accuracy

Abstract

The microphysics of reconnection, sharp boundaries, shocks and turbulence are at the forefront of space plasma physics research. In all of these cases, the component of the electric field parallel to the local magnetic field (the parallel electric field) plays a key role. To obtain this component, one must measure the three-component electric and magnetic field accurately because the parallel electric field is typically an order-of-magnitude smaller than the perpendicular electric field. Spacecrafts that have measured such electric fields have been spin stabilized, so the spin-axis measurement, made with a much shorter antenna than the spin plane wire boom measurements, does not have the required sensitivity. However, for both field and plasma measurements, it is highly desirable to make measurements in the spin planes of two rotating platforms because major advancements of science are expected from such data. For the purpose of obtaining such measurements, a new spacecraft architecture has been studied. It consists of a fixed center body with one surface, holding solar panels, pointing sunward, magnetometer for the second measurement, with counter-rotating platforms on two other surfaces aligned at 90 degrees to each other. This paper will review in more detail the science motivations for the spacecraft configuration; a straw-man design of the spacecraft and it will describe the modeling and control of such a system. This paper also analyzed the dynamics of this structure and proposed a control structure to maintain its attitude to prevent tangle of the booms.