AOCS DESIGN FOR A 160-m, 450-kg SOLAR SAIL SPACECRAFT OF THE SOLAR POLAR IMAGER MISSION

摘要

An attitude and orbit control system (AOCS) is developedrnfor a 160-m, 450-kg solar sail spacecraft of the Solar PolarrnImager (SPI) mission. The SPI sailcraft first spiralsrninwards from 1 AU to a heliocentric circular orbit at 0.48rnAU, followed by a cranking orbit phase to achieve a sciencernmission orbit at a 75-deg inclination, over a totalrnsailing time of 6.6 yr. The solar sail will be jettisonedrnafter achieving the science mission orbit. This paper focusesrnon the solar sailing phase of the SPI mission, withrnemphasis on the design of a baseline AOCS consisting ofrna propellantless primary ACS and a microthruster-basedrnsecondary (backup) ACS. A 70-deg pitch reorientationrnwithin 3 hrs every half orbit during the orbit crankingrnphase is shown to be feasible for possible solar observationsrneven during the 5-yr cranking orbit phase.