Lely CANopen in space

Last year, the European Space Agency (ESA) issued an invitation to tender for the development of an open-source implementation of the CANopen protocol suitable for space applications. In particular, an implementation of the ECSS-E-ST-50-15C - CANbus extension protocol with accompanying test suite. The Lely CANopen stack was one of the candidates considered to be a promising starting point for such a development. N7 Space submitted a proposal based on our stack and won the bid. Since the beginning of this year, they have been working, with support from Lely, to improve and extend the stack and to develop a comprehensive test suite. This work is carried out under a programme of, and funded by, the European Space Agency.

Several of their improvements have already found their way back into recent releases. And even more will be part of the upcoming v2.3 release. However, some changes require us to break the backward compatibility of part of the C API. For example, one of the ESA requirements is that the stack can be used with (almost) no support from the standard C library. Supporting such a freestanding environment, with no dynamic memory allocation, affects several public interfaces.

Breaking changes warrant an increase in the major version number. For now, v3 is under development in the ecss branch at https://gitlab.com/n7space/canopen/lely-core. The first releases mark milestones in the ESA project. Once it is finished, the ecss branch will be merged into the official repository and released publicly, probably with version 3.3. Non-breaking changes will continue to be merged into v2.x releases.

Disclaimer: The views expressed here can in no way be taken to reflect the official opinion of the European Space Agency.