Title of Presentation: Development of the Balloon Arc Second Pointing System

Primary (Corresponding) Author: Philip R. Ward

Organization of Primary Author: NASA Wallops Flight Facility

Abstract: NASA’s Scientific Balloon Program affords researchers the opportunity to conduct research in a near-space environment. Flight altitudes of 120k feet are typical, which place the balloons above more than 99½% of the earth’s atmosphere. This naturally makes them attractive platforms on which to mount space-viewing telescopes. In order to successfully utilize balloons as platforms for telescopes to, for example, search for extraterrestrial planets, requires a means of pointing the instrument at the intended target within the required accuracy and jitter limits. A major hurdle in extending the range of experiments for which balloon vehicles are useful has been the imposition of the gondola dynamics on the accuracy with which an instrument can be kept pointed at a celestial target. In this paper, the foundation for a high fidelity controller simulation is presented and it is shown that sub-arcsecond pointing stability can be achieved for a large instrument pointing at an inertial target. This paper establishes that the proposed control strategy can be made robustly stable with significant design margins. Also demonstrated is the efficacy of the proposed system in rejecting disturbances larger than those considered realistic.