Cooperative Automated Systems enable new kinds of applications and services. Corresponding visions stretch across virtually any domain of embedded systems and it is obvious that there lies a huge potential for economic, ecologic and societal improvements and success. However, to unlock this potential we first need to overcome diverse engineering challenges. Most importantly, we need to be able to ensure safety of such systems. Unfortunately, established safety assurance methods and standards do not live up to this task as they have been designed with closed deterministic systems in mind. This paper structures safety assurance challenges of cooperative automated systems and provides an overview and discussion on corresponding solution approaches.