Moon Day focuses growing concerns around space junk

As global attention turns toward the Moon on International Moon Day, July 20, the occasion has become a focal point for raising awareness about the escalating issue of space debris. The United Nations, through the UN Environment Programme (UNEP), is emphasizing the need for sustainable practices in space exploration amid growing concerns about the environmental impact of increased orbital activity. According to Jason Jabbour, a senior officer at UNEP, decades of rapid expansion in space missions have left behind a legacy of environmental footprints, many of which are still being studied for their full effects. The accumulation of space debris poses a critical challenge. An estimated 140 million fragments larger than one millimetre currently orbit Earth, with the majority too small to track yet still capable of damaging satellites and spacecraft. These remnants include defunct satellites, detachable rocket parts, and smaller mission-related items such as bolts and lens caps. As satellite constellations expand, the number of objects in orbit continues to rise, increasing the likelihood of collisions and creating even more debris. Environmental scientists warn that the re-entry of spacecraft and rocket bodies into Earth's atmosphere releases metals like aluminum, lithium, and copper. Researchers are investigating whether these materials might alter atmospheric chemistry, influence cloud formation, and potentially harm the ozone layer. Additionally, the fragmentation of rockets and spacecraft, often due to collisions or explosions, produces microscopic particles that may be contributing to the brightening of the night sky, a phenomenon known as artificial light pollution. The risks associated with space debris extend beyond the immediate threat of collision. Larger components of spacecraft that survive re-entry can pose dangers to people, infrastructure, and marine life. For instance, some rocket parts remain in orbit for years before breaking apart or descending back to Earth, while others disintegrate into thousands of pieces. It is estimated that hundreds of tonnes of spacecraft and rocket bodies re-enter the atmosphere annually, a figure projected to rise significantly as more nations and private entities engage in space exploration. International efforts to mitigate these issues have been ongoing. The United Nations has adopted guidelines aimed at limiting the creation of space debris by reducing unnecessary waste, preventing explosions, and ensuring the safe removal of retired satellites and rocket stages from orbit. Under the 1972 UN Liability Convention, countries responsible for launching space objects are held accountable for any damage caused by them on Earth, including incidents involving joint launches. The significance of the Moon in both cultural and ecological contexts adds urgency to these discussions. From its distant vantage point, the Moon influences Earth’s tides, which play a crucial role in oxygenating coastal waters and sustaining marine ecosystems such as the Great Barrier Reef. Understanding the Moon also provides insights into the origins and evolution of the solar system. Recent lunar missions, such as NASA’s Artemis II, highlight the renewed interest in exploring the Moon, with plans to establish a long-term human presence there during the 2030s. As space agencies and private companies continue to push the boundaries of exploration, the need for sustainable practices becomes increasingly apparent. Collaborative efforts between organizations like UNEP and the UN Office for Outer Space Affairs aim to enhance scientific understanding and develop strategies to protect the space environment for future generations. With the number of active satellites and space missions set to increase, addressing the environmental consequences of space exploration will require sustained international cooperation and innovation.