The open-source real-time OS RTEMS has become quite popular in the Space Domain. Particularly with its Symmetric Multi Processing (SMP) option it may provide a very efficient use of multicore processors. In order to permit its application in more critical space missions, attempts have been made for a qualification according to ECSS standards. As an innovative approach the qualification is organised in form of an open-source approach as well. Funded by ESA a consortium with different contractors is preparing a qualification toolkit that shall be made available to the public. This qualification toolkit will provide tool-chain and test-suite for a mostly automated generation of qualification documents on level C and D, together with a basic set of interfaces for the most common system on chips used in the space domain. A later independent verification and validation is anticipated to obtain a level B qualification. Compared to proprietary software this approach shall lower the required investments and reduce the dependency to sole software providers. The presentation will provide an overview of the available software resources as well as the test equipment. It will further explain how to use those resources in order to prepare the qualification of a set application software and provide an outlook on expected future extensions and additional resources. A very special aspect is the open-source approach for qualification. After the initial steps have been supported by ESA, a continuation and extension of the database has to be organised in an open, self-organised process. Such a process will need to be established in order to sustain the use of the qualification toolkit in future environments without extensive re-developments.