Computador de Bordo para Nanossatélites em Órbita Baixa no Padrão CubeSat

Abstract

In recent decades, CubeSat nanosatellites have made it possible for universities and small companies to study these technologies and go to space. In this context, the National Institute of Spatial Research (INPE) proposed the CONASAT project, which has as its goal to update the Brazilian Environmental Data Collection System (BDCS), replacing the old satellites with a new CubeSat constellation. The BDCS, beyond satellites, is also composed of ground stations and Data Collection Platforms (DCPs) spread across the Brazilian territory. This paper presents the design of an onboard computer (OBC), made of components off-the-shelf (COTS), for low-orbit CubeSat satellites. Aiming to obtain the requisites for digital systems in low- orbit, it proposes the electronic schematic and the printed circuit board (PCB) of an onboard computer compatible with the architecture and with all subsystems of the first satellite in the BDCS constellation, the CONASAT-01, as well as the software and operating system required for the mission. The developed board embeds FreeRTOS on an STM32 microcontroller to manage and execute the missions’ tasks, such as housekeeping, supervising telecommand & telemetry, and sending and receiving data from ground stations. All the communications drivers were also developed. The nationalization of the OBC compatible with the scheduled mission and with the global market is one of the main contributions of this paper: it strengthens Brazilian satellite research as it helps to develop the next CONASAT CubeSats.