Design of a flexible nanosatellite bus for science missions

This paper focuses on the design issues of ITUpSAT II which is the second nanosatellite project of the Controls and Avionics Laboratory of ITU. The idea ITUpSAT II is to develop a standardized but reconfigurable bus architecture which can serve as a standard platform for a variety of space science missions. The configuration is compliant with 3U CubeSat Standards as to enable simple access to space. In addition, the design mainly utilizes in-house space-modified COTS components as to reduce the manufacturing costs. In comparison to the existing on-market pico/nano-satellite buses, ITUpSAT II bus provides not only higher computational power and data link capabilities but also precise orbit determination through its GPS receiver. To cope up with different requirements across a wide range of scientific missions, an indigenous ADCS for precise attitude control is developed. Embedded within the ADCS is a suite of attitude determination and controller algorithms with different operation modes as to fulfill the pointing accuracy needs depending on the mission. Furthermore, the modular subsystem structure enables ADCS and S-Band data link to serve as a standalone payload computer.