Space exploration carries immense scientific, technological, and inspirational value, yet the propulsion systems, spacecraft, and infrastructure it depends on leave a measurable footprint on both outer space and Earth. Orbital debris, atmospheric pollutants from launches, and the risk of biological contamination of celestial bodies now pose direct threats to the long-term viability of the very activity that produces them. This article examines the tension between scientific exploration and environmental protection in space, situating it within existing legal frameworks — principally the Outer Space Treaty of 1967, the Liability Convention, the Moon Agreement, and the non-binding UN Space Debris Mitigation Guidelines, alongside emerging soft-law and industry initiatives such as COSPAR’s Planetary Protection Policy, the Artemis Accords, and the World Economic Forum’s Space Sustainability Rating. It argues that the absence of a binding legal definition of “space debris,” combined with the voluntary character of existing mitigation guidelines, has produced a governance gap that disproportionately disadvantages developing and emerging space-faring states, which lack the resources to absorb the costs of a purely self-regulating regime. Drawing on recent technological developments like green propulsion, reusable launch vehicles, active debris removal, and in-orbit servicing, the article contends that technological innovation alone cannot substitute for binding international regulation, and that the two must develop in tandem. It concludes with concrete recommendations for treaty reform, mandatory debris mitigation standards, and capacity-building mechanisms aimed at ensuring that outer space remains, in the language of the Outer Space Treaty, the “province of all mankind” rather than a common resource degraded by the states best able to exploit it first.