Humankind’s exploration and use of outer space are first and foremost limited by the obligation of non-appropriation. This prohibition, with an aim to prevent conflicts arising from competing territorial claims, does not extend to the exploitation of abiotic resources in space. Recent state practice has shown a clear trend of regarding such exploitation as a freedom of exploration and use of outer space. The future international legal regime should prohibit property claims over natural resources in place on celestial bodies, avoid the controversial issue of ownership, co-ordinate the resource activities of different entities by a stage-specific and priority-right-based mechanism, and harden the obligations of capacity-building and co-operation. The ideas of parallel system and monetary benefit sharing should not be discarded although resistance from major space-faring countries is foreseeable.

In recent years, there has been a surge of private investment in space resources and the enactment of domestic legislation aimed at protecting property rights over the resources to be extracted. This article argues that the unilateral exploitation of space resources is not prohibited by the principle of non-appropriation and is consistent with the freedom of use for common benefit and interests, with the caveat that it does not exclude others from exploitation or exacerbate inequality among States. It also argues that a laissez-faire approach would be detrimental to the orderly, sustainable and safe exploitation and use of space resources and calls for the establishment of an international regulatory regime consisting of rules concerning international coordination, benefits sharing and environmental protection.