This paper discusses how some important articles of the 1967 Outer Space Treaty (OST) have been construed by subsequent state practice, taking into account the changing dynamics of space governance. The article, based on a doctrinal methodology and inspired by Articles 31 and 32 of the Vienna Convention on the Law of Treaties (VCLT), explores how nations have operationalized and amended the legal meaning of treaty obligations without explicitly revising the language. It examines how national legislation, and soft law instruments have reshaped these principles in response to the hurdles of privatization, commercialization, and orbital congestion. It focuses on three critical provisions of the OST: Article II (non-appropriation), Article VII (launching state liability), and Article IX (environmental contamination). The analysis shows that domestic laws allowing commercial resource extraction have extended the concept of non-appropriation, whilst the liability system has changed through national frameworks and indemnification arrangements in response to the development of private entities. Meanwhile, environmental duties under Article IX have been gradually defined by generally recognized non-binding regulations such as the Space Debris Mitigation Guidelines and the Long-Term Sustainability Guidelines.