Open Source Summit Europe 2024

Linux in space must be highly reliable and autonomous, both because of the hostile external environment, the physical unavailability of the system, and the limited data flow and direct system administration capabilities. Radiation and other external influences lead to sudden shutdowns and system reboots. Also, data stored in storage devices are at risk of radiation and physical effects. Therefore, the design of a satellite always considers which parts of the system to duplicate or otherwise insure and how to ensure the system's ability to detect an error and recover. In the design of Linux4Space, we have encountered various approaches to solving the problem (from "we have two SD cards, and one is sure to last six months" to "fully duplicated storage and CPU with error detection"). We have reviewed the designs of other satellites and systems. In this paper, we provide some specific examples from natural satellites and summarize everything we have been able to find and track down for various other solutions, examples, and demonstrations.