In recent years, the concept of ‘responsible behavior’ in the context of space activities has appeared more and more frequently on the international scene. Although everyone seems to agree on the need to behave ‘responsibly’ in space, the whole debate is far from being adequately defined. This paper suggests that ‘responsible behavior’ should also govern and delimit the exploitation and use of space resources. Responsible behavior in this respect will be defined by Article IX OST, in particular by the ‘due regard’ principle, the willingness of States to cooperate internationally but also to promote a sustainable use of these resources. Further, the prospect of permanent human space settlements will redirect the approaches (political-legal) to the issue of space resources, depending on the stance that these communities will take on this issue. The different possible scenarios may redefine what is considered ‘responsible’, with a corresponding impact on the relevant legal frameworks.