This report is focused on safety for unmanned aerial systems and has been prepared within the framework of the research and technology theme Unmanned vehicles and cyberthreats, which progresses during the years 2012-2014. The theme aims to formulate and analyze proposals on concepts for unmanned aerial systems and evaluate the possibilities of how such systems can complement conventional territorial surveilance systems and be operational environment from 2030. Systems, or parts of systems, should have the flexibility to be used in international operations and activities, and be protected against cyber threats. Aspects of cost efficiency and organizational consequences for the Swedish Armed Forces are important areas to highlight. Use of unmanned aircraft systems in unrestricted airspace, i.e. integration of UAS in airspace used by manned aircraft, will put great demands on safety for unmanned aircraft. One general goal of the global work is safety of unmanned flight to be comparable to that of manned flight. Policies must therefore be developed to define what is an acceptable risk in order to operate in integrated airspace and over inhabited areas. Unmanned systems must also be certified (with respect to safety), a process where the aircraft, one or more ground stations (including interfaces), and communication links are analyzed to verify that the system and its parts fulfill the requirements put on it. To compensate for the lack of a human pilot, new technologies need to be developed and certified. Important is a system for detecting other aircraft nearby to follow and avoid collisions with these. This will replace the ability that a human pilot has to see and avoid other vehicles or objects. Another important aspect of safety is the degree of automation. The development of automated systems produces more capable systems than ever before, though they continue to be remotely piloted and will do so for the foreseeable future. A high level of flight safety requires that the parts of a system can handle situations where contact with an unmanned vehicle is lost and the pilot cannot control the craft directly. It is thus important to develop proper routines for such situations.