B. Lakshmi Narayana, H. N. Suresha Kumar, G. Nagesh and B. S. Nataraju
ABSTRACT: The solar array of INSAT-3A spacecraft is configured to have a yoke, three main panels and two side panels. The yoke is connected to the satellite through Solar Array Drive Assembly (SADA). The yoke and three main panels are deployed during primary deployment. The two side panels, which are of the same size as the first panel and kept folded on either side of first panel, are deployed during secondary deployment. The deployment of side panels and their subsequent locking produces reactive torque at SADA. This rotates the entire solar array during deployment and also after latch-up. The rotation of the array is about the pitch axis, overcoming the detent torque and friction torque at SADA. The extent of rotation during and after deployment depends on the magnitude of the detent torque and friction torque in SADA. Using the software ADAMS, numerical studies have been carried out simulating the on-orbit deployment of side panels. The spacecraft is considered to be in free-free condition. The objective of this study is to predict the deployment time, latch-up velocity, SADA rotation during and after deployment and body rates of spacecraft about pitch axis. This paper presents the details of the study. A comparison of analysis results with the on-orbit observations has also been provided.
KEYWORDS: Deployment mechanism, Solar panel deployment, Spacecraft Body rates, ADAMS, Simulation
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