Linux for Space - Mission Begins
Lenka Kosková Třísková & Lukáš Mázl, Technical University of Liberec [Open Source Summit EU 2022]

A few research and development institutes in Czech republic working on space came together to start something similar to Automotive Linux for space because nothing exists yet.

The aim is to have a yocto based reference distribution suitable for space applications.

In space, not many people are familiar with linux because they’re physics etc.

It has to be compliant to ESA standards.

The hardware used in space starts to be ready for Linux, more and more ARM for example. However, each hardware supplies builds their own Linux distribution, similar to the situation for Automotive 10 years ago.

Space is strictly defined, also what can go wrong. This leads to a number of requirements before implementation is started. These have been collected and are being defined now. In 2023 they want to start building a yocto distribution and start compliance work.

Hard radiation and low power means that the system may switch off at any time, so the system must be able to deal with that. There may also be errors in files, or they may be temporarily inaccessible. There are parallel instances of the system for reliablilty. Every process gets a power budget that may not be exceeded.

Typical interfaces used in space: spacewire, spacefibre (both closed protocols, but an open source implementation should be allowed), and CubeSat Space Protocol. They’ll start with the latter.

Currently available requirements version 001, a dictionary, draft of yocto implementation strategy (not published yet). There are regular community meetings which anyone can join.

One of the partners is going to provide a board for testing. It’s an ARM based board that has already been tested in space. But they also plan to make a RPi build so anyone can play with it.

Applications like CubeSat stay close to earth where radiation is less bad, so there are more possibilities for bigger, less tested processors. For deep space missions they still need to use Leon etc. which have been heavily tested in hard radiation.

Note that linux is only used for the payloads, not for the main processor (incl. navigation) uses an RTOS. For the payloads it makes sense to use linux because it makes some complicated things that need to be done (e.g. image processing) much easier.