WSEAS Transactions on Systems
Print ISSN: 1109-2777, E-ISSN: 2224-2678
Volume 19, 2020
Initial Attitude Acquisition in-orbit Status of ALSAT-2A Remote Sensing Satellite
Author:
Abstract: In this paper we present the in orbit performance during the initial attitude acquisition, immediately after separation from the final stage of the launcher, until the satellite converges toward a sun pointing. On 12th july 2010 ALSAT-2A microsatellite was launched into a 670 km sun synchronous orbit, with a solar local time at an ascending node of 22h15. In the initial acquisition mode or even in the safe mode, only sun sensors and magnetometer are used for attitude determination. Knowing that, the satellite once is separated from the launcher it starts tumbling. So, as to detumble the satellite, a strategy consisting of three phases is set. The first phase consists on reducing the velocity using only the magnetorquers, until reaching the threshold angular momentum of 0.05 Nms, once this is done, the second phase is automatically enabled in such a way, the four reaction wheels are ON and speed up to get an angular momentum of -0.15 Nms along the satellite x-axis. At the end of this phase the satellite is completely detumbled and a third phase is carried out, in which the satellite minus X axis is pointed toward sun with a small rotation.
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Pages: 62-67
DOI: 10.37394/23202.2020.19.9