The article examines an urgent problem related to modern international space law and the interstate conflict over the imperative prohibition of national appropriation of celestial bodies and the emerging practice of unilateral appropriation of space resources, legitimized by national laws. The author analyzes the philosophical and legal foundations of the "Common Heritage of Mankind" and "National Appropriation" concepts, revealing their roots in the doctrines of J. Rawls and J. Locke. The scientific novelty lies in proposing an original "Criteria-Based Model" for differentiating legal regimes based on the type of resource, the scale of extraction, and its intended purpose. The conclusion is made about the necessity of forming a new international legal paradigm to balance the interests of private initiative, states, and all mankind.