This Ph.D. thesis explores the international legal regulation on protecting outer space environment from different types of space debris. My research focuses on the international legal gaps to regulate all major aspects of space debris and the challenges in front of comprehensive international cooperation and legal regulation. Analysing levels of cooperation, achievements and omissions in different international forums that address the issue of space debris is provided. The research concludes that unless comprehensive cooperation is achieved on a global level and new international legal treaties are not established, potential military conflicts could emerge amongst spacefaring nations over the right to exploit outer space resources. This thesis, then, illustrates different challenges of different space debris and proposes ways to address them. This research also investigates the roles of international governmental organizations as well as international scientific organizations to address the issues of space debris production, management, and removal from outer space. Therefore, the thesis provides the steps to improve traffic management in space to provide safety to all space activities while achieving better protection of the outer space environment. My dissertation contains five chapters. The first chapter talks about the research questions, research objectives, methodology and the logic of the structure of the thesis. The second chapter of my dissertation thesis explores into the definitions of the main terms such as space object, space debris, aerospace object and others. It analyses the legal norms, relevant to the space debris issue and explores the need to adopt new international legal norms. This chapter also investigates the most important legal terms, related to the space debris issue, such as ownership, jurisdiction and control over space debris. This chapter also includes the classification of different types of space debris vi and the different types of threats that they represent to space activities and to people on Earth. International space debris regulation has different aspects, which have to be explored in order to draw a complete picture and analyse the problem from different perspectives. These perspectives include the legality of the creation of space debris, and the different dangers from it, based on the chemical structure, size, location, traceability and the risk of loss of life and property in space and on Earth. Analysing the legal definition of “harmful contamination” and its scope in the creation of space debris is an important part of this chapter. Environmental protection of outer space and of Earth from space debris is also significant in this chapter. The legal issue of international liability is reviewed and analysed. The latest examples of good national practices to reduce the risk from space debris are also identified and analysed in the research thesis. Special focus is placed on the public-private partnership in space activities. Chapter three focuses on analysing the achievements and failures in international efforts of states to improve the safety of the outer space environment. This chapter is devoted to analysing the positive as well as the negative aspects of such international cooperation on a state level. The main challenges of international cooperation are explored in the last subchapter of this chapter. The main purpose of chapter three is to provide an analysis and overview of the relevant leading intergovernmental organizations and international scientific organizations in the field of international space law. These organizations are UNCOPUOS, Inter-Agency Space Debris Coordination Committee, ITU, COSPAR, International Law Association and the Conference on Disarmament. Separate subchapters in this section discuss the international cooperation on banning anti-satellite tests and taking a look at the European regional structures that are involved in the mitigation of space debris. The European projects, investments, and institutional capacities are analysed from the vii perspective of regional cooperation that could produce good institutional practices for global cooperation. Comparative analysis of different national space policies that discuss methods to reduce the threats from space debris is separately provided in a subchapter. Chapter four explores the most significant proposals, according to the author, in international law to resolve the problems related to space debris. The proposals have been selected on two distinct criteria: 1) from authors, who have published extensively in the field of international space law and 2) the proposals that distinguish themselves with originality and logic to address the issue of space debris. The last chapter presents comprehensive resolution of the challenges from space debris production. I propose the establishment of an International Space Agency. This sui generis international organization includes most nations that dedicate themselves to protecting the interests of humankind as well as those of states and private actors. The holistic vision of outer space exploration is key to solving the problems in outer space policies, including the massive creation of space debris and their poor management. This dissertation also suggests the adoption of a global planetary quarantine protocol for the protection of the Earth from returning space objects, infection by space organisms, nuclear explosions of nuclear-powered satellites and improvements in present international bodies, which are regulating aspects of space debris. The research aims to provide recommendations on how to deal with space debris on a global level. Although national measures adopted by space-faring states could be very useful in achieving better protection of outer space environment, the measures would not be sufficient because other states will not have the obligations to adopt them. Comprehensive international cooperation in dealing with the negative effects of space debris is essential, particularly with respect to sharing information about activities in viii outer space, traffic management and adoption of common standards for shielding space objects and common mitigation guidelines