Developing a Linux-based nanosatellite on-board computer: Flight results from the Aalto-1 mission

The on-board computers of a spacecraft handle telecommands sent by the ground, provide telemetry to the ground, process on-board data, and control the spacecraft platform and payloads. A spacecraft may have one or several on-board computers that handle different tasks. On -board software often makes use of specialized real-time operating systems and is usually tailored to the needs of each mission, leading to software projects spanning several years. Additionally, often only parts of the developed software can be used in following missions, demanding a new long software project for the new mission -even when much of the functionality may be very similar from one mission to another. One method to facilitate software reuse is to use existing off the -shelf software modules to accomplish many of the mission tasks while only writing a small portion of mission -specific application code. One way to achieve this, used especially by universities and "new space" companies, has been to use embedded Linux [1]. However, only some of these projects have published how they built their Linux-based on -board software systems. This article describes the development, design, initial fl ight results, and lessons learned of the Linux-based on -board computer (OBC) of Aalto-1.