If all goes as planned NASAs Artemis II crew fresh off a record-breakng orbit of the Moon will splash down in the Pacific Ocean later today.
But before they do, the four astronauts and their Orion spacecraft will pass through a band of the upper atmosphere that is rife with litter.
How much junk is up there? Well, a recent issues note from the United Nations says there are 130 million pieces of debris orbiting the Earth, from satellite fragments to abandoned spacecraft. Some hurtle around the planet at up to 15km per second, 10 times the speed of a bullet, says NASA.
Litter is just one of several environmental challenges linked to humanitys rapidly expanding presence in outer space, found the UN issues note.
To mark the return of the Artemis crew, and celebrate the International Day of Human Space Flight, lets answer six key questions about space-related pollution.
1. Do rockets cause pollution?
Yes, they do. Every rocket launch releases soot, aluminium particles, chemical compounds and gases into the atmosphere. These emissions can influence atmospheric chemistry, increase air pollution and damage the ozone layer.
But it is not just launches that pack an environmental punch. As spacecraft re-enter the atmosphere, they leave behind a chemical trail of oxides and metals. These pollutants can deplete ozone and potentially affect how much sunlight gets reflected back into space, found the UN issues note, a joint production of the UN Environment Programme (UNEP) and UN Office for Outer Space Affairs.
2. Why is space litter dangerous?
Theres the growing cloud of debris forming around our planet. Old satellites and fragments from collisions are accumulating, heightening the risk of impacts that create more space debris. If these items stay in space, they can crash into the satellites we rely on. If they survive re-entry, they can fall back to Earth, posing risks for communities and ecosystems.
Large satellite constellations and orbital debris are also making the night sky brighter and noisier, interfering with astronomy and our ability to study the universe.
3. How can the world reduce the environmental footprint of space-faring?
First, we need to close knowledge gaps. More research is needed to understand the full environmental impact of space activities on the atmosphere, the climate, ecosystems and people.
Second, monitoring and data-sharing must improve. Better data, especially on emissions launches and re-entry, will help track risks, predict impacts and bolster responses.
Third, spacecraft need to be designed in ways that lessen their environmental impact throughout their lifecycles.
This includes building crafts that can avoid collisions, safely de-orbit and run on cleaner fuels.
Finally, stronger international cooperation is essential. Governments, space agencies, private companies and scientists must work together to establish and apply global sustainability standards before challenges escalate.
4. What does the term space sustainability mean?
Space sustainability refers to using outer space in a way that protects both space itself and Earths environment over the long term. In essence, it means treating space as a shared environment that must remain safe and usable for future generations. This means:
- minimizing debris;
- reducing emissions;
- protecting dark and quiet skies;
- using resources efficiently;
- ensuringthe safe re-entry of spacecraft; and
- maintaining equitable access to space
5. Who is responsible for managing space-related environment challenges?
This is a shared responsibility.
International agreements, like the Outer Space Treaty, set broad principles, including the avoidance of harmful contamination. The UN Committee on the Peaceful Uses of Outer Space develops guidelines for sustainable space activities, while national governments regulate launches, satellite operations and licensing.
Companies and agencies are responsible for designing and operating technologies that reduce environmental harm.
Other bodies also play key roles. The International Telecommunication Union manages satellite orbits and radio frequencies, while the International Maritime Organization is examining impacts on oceans.
But there is still no comprehensive global environmental framework for space.
6. What is the role of the United Nations?
As space activities increasingly affect our atmosphere, oceans, ecosystems and communities, the United Nations is stepping in to help bridge this gap.
UNEP and the UN Office for Outer Space Affairs are working together to better understand environmental risks, strengthen the scientific evidence base, and ensure that environmental considerations and space governance go hand-in-hand.
What happens in space is no longer separate from what is happening on Earth. But with strong global cooperation and action, countries can keep this frontier free from environmental crisis.
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Written by Alyona Synenko
Scientifically reviewed by Andrea Hinwood
