Outer space security is becoming one of the most pressing global concerns, with serious implications for world peace and the future of space exploration. Its importance has enhanced with the doomsday scenario being painted by climate catastrophes, whose frequency and intensity is enhancing. The article outlines theoretical framework of securitization to explain how space has transitioned from a domain of peaceful exploration to one of strategic military significance. It also examines the impact of space securitisation on international relations. In this backdrop, the article argues that the space-faring nations are heading towards a competitive and often contentious environment because of securitization of space. Moreover, the twin fold feature of many space technologies, which can be utilised for both military and civilian purposes, complicate efforts to regulate and manage space activities. The militarisation and potential weapons deployment in space, pose significant challenges to existing international treaties and agreements meant for preserving the use of outer space for global peace and security.