Design of a cubesat computer architecture using COTS hardware for terrestrial thermal imaging

CubeSats are standardized artificial nano satellites which weigh between 1 and 15kg and serve the purpose of space research. A handful of cubesats have proved their worth to the world with their payloads based on terrestrial monitoring. The so-called remote sensing cubesats have revolutionized the platform for different scientific observations that include weather forecast, cyclone warning systems, visible and thermal terrestrial imaging, sea surface temperature monitoring, forest fire detection and so on. An onboard computer (OBC) acts like the brain of any satellite. This system is expected to perform multifarious activities by monitoring and controlling every function of the satellite. In this paper, we discuss the design of a dual processor based onboard computer system built solely on commercially-off the-shelf (COTS) components. The design technologies for large commercial satellites cannot be directly used for the nano satellite due to the compactness of OBC. This paper will cover the functionality of a satellite OBC and detail how COTS hardware supports the activities. Focus will be mainly given to the payload electronics which is a thermal imaging system with capability of real time autonomous cloud monitoring. The system is designed by taking into account, the low power availability in nano satellite missions. A dual controller based system is designed and various aspects of the component interfacing are also shown.