Moon Day Spotlights Growing Risks From Space Junk

NASA Earth rises behind the Moon as pictured from the Artemis II mission.

The United Nations on Monday warned that the new era of lunar exploration must not come at the expense of Earth's environment or the long-term sustainability of outer space, as countries intensify plans to return to the Moon.

Marking International Moon Day, the UN called on governments and space agencies to place environmental protection at the centre of future space missions, citing growing concerns over the rapid increase in space debris and its potential impact on Earth and the space environment.

"Decades of rapidly expanding space activity have shown that every launch leaves an environmental footprint, and it can take a long time to fully understand its impact," said Jason Jabbour, Senior Officer at the UN Environment Programme (UNEP).

"That is why it is so important to consider sustainability from the very beginning of every space programme," he added.

The warning comes as global interest in lunar exploration reaches its highest level in decades. Earlier this year, NASA's Artemis II mission carried four astronauts on a 10-day journey around the Moon, marking a major step toward establishing a long-term human presence on the lunar surface during the 2030s. China, India, Japan and several private companies are also advancing ambitious lunar programmes.

The UN, however, warned that increasing space activity is being accompanied by a sharp rise in orbital pollution.

According to UN estimates, around 140 million pieces of space debris larger than one millimetre are currently orbiting Earth. While most fragments are too small to track, they travel at extremely high speeds and pose serious risks to satellites, spacecraft and future missions.

Scientists are also examining the environmental effects of satellites and rocket components re-entering Earth's atmosphere. During re-entry, spacecraft release metals such as aluminium, lithium and copper, which could affect atmospheric chemistry, cloud formation and the ozone layer.

Discarded rocket stages, broken satellite fragments and even small objects such as bolts, protective covers and lens caps are contributing to orbital congestion. Collisions between debris create countless microscopic particles that researchers believe are already making the night sky brighter.

Although most spacecraft burn up before reaching the ground, larger heat-resistant components can survive re-entry, posing potential risks to people, infrastructure and marine ecosystems.

The UN stressed that preserving outer space is becoming as important as protecting Earth's environment.

International agreements already prohibit harmful contamination of outer space, while UN member states have adopted guidelines to minimise debris, prevent accidental explosions in orbit, avoid the deliberate destruction of spacecraft and safely remove retired satellites and rocket bodies.

Under the 1972 UN Liability Convention, countries remain legally responsible for damage caused on Earth by spacecraft they launch, including jointly operated missions.

To address emerging environmental challenges, UNEP and the UN Office for Outer Space Affairs are expanding research into the ecological impacts of space activities and working to integrate environmental protection into future global space governance.

The UN noted that the Moon continues to play a vital role in sustaining life on Earth by influencing ocean tides that help circulate nutrients, oxygenate coastal waters and support marine ecosystems, underscoring the need for responsible exploration as humanity prepares for a sustained return to its nearest celestial neighbour.