with the intent to create more specific legal provisions later (Griffin, 1981: 733–734). This is why the members of the COPUOS later expanded the Outer Space Treaty norms by articulating more specific understandings which are found in the "three supplemental agreements" – the Rescue and Return Agreement of 1968, the Liability Convention of 1973, and the Registration Convention of 1976 (734). Hobe (2007) explains that the Outer Space Treaty "explicitly and implicitly prohibits only the acquisition of territorial property rights" but extracting space resources is allowable. It is generally understood within the space law authorities that extracting space resources is allowable, even by private companies for profit. However, international space law prohibits property rights over territories and outer space land. Hobe further explains that there is no mention of “the question of the extraction of natural resources which means that such use is allowed under the Outer Space Treaty” (2007: 211). He also points out that there is an unsettled question regarding the division of benefits from outer space resources in accordance with Article, paragraph 1 of the Outer Space Treaty. The Moon Agreement The Moon Agreement was signed on December 18, 1979, as part of the United Nations Charter and it entered into force in 1984 after a five state ratification consensus procedure, agreed upon by the members of the United Nations Committee on Peaceful Uses of Outer Space (COPUOS). As of September 2019, only 18 nations have signed or ratified the treaty. The other three outer space treaties experienced a high level of international cooperation in terms of signage and ratification, but the Moon Treaty went further than them, by defining the Common Heritage concept in more detail and by imposing specific obligations on the parties engaged in the exploration and/or exploitation of outer space. The Moon Treaty explicitly designates the Moon and its natural resources as part of the Common Heritage of Mankind. The Article 11 establishes that lunar resources are "not subject to national appropriation by claim of sovereignty, by means of use or occupation, or by any other means". However, exploitation of resources is suggested to be allowed if it is "governed by an international regime" (Article 11.5), but the rules of such regime have not yet been established. S. Neil Hosenball, the NASA General Counsel and chief US negotiator for the Moon Treaty, cautioned in 2018 that negotiation of the rules of the international