Climate footprint of space exploration is passing below the radar Premium

Urgent need for international regulations to address environmental consequences of space activities to ensure sustainability and prevent harm.

As the world becomes more reliant on space technologies for vital functions like climate monitoring, the environmental consequences of space activities also become increasingly urgent and in need of more attention. The rapid growth of the number of satellites in orbit has led to concerns about interference with climate monitoring systems and the accumulation of orbital debris. With no specific international regulations addressing these challenges, it is crucial the world’s governments act quickly to ensure space exploration doesn’t drift into unsustainability.

Every rocket launch releases carbon dioxide, black carbon, and water vapour into the atmosphere. Black carbon is of particular concern because it absorbs sunlight 500-times more effectively than carbon dioxide does, amplifying global warming. As commercial space ventures become more common, the cumulative impact of these emissions will worsen.

Rocket propellants, especially those using chlorine-based chemicals, deplete the ozone layer at high altitudes, increasing exposure to ultraviolet radiation on the ground as well as disrupting atmospheric circulation — both of which affect the global climate. According to a December 9 article in MIT Tech Review, when satellites “burn up in the atmosphere” once their missions end, they release “satellite ash in the middle layers of the earth’s atmosphere. This metallic ash can harm the atmosphere and potentially alter the climate.“

Next, like many other forms of manufacturing, the production of satellites demands energy-intensive processes involving metals and composite materials, whose extraction and preparation have large carbon footprints of their own. Satellites also use propulsion systems to adjust their location and orientation in orbit, and their emissions add to the overall count. Equally, the rise of space mining — e.g. extracting valuable (on the earth) minerals from asteroids — could lead to increased industrial activity both in space and on the ground. Such mining activities haven’t begun yet but they are sure to be part of the future.

While space technology supports essential climate monitoring and disaster management, the environmental costs for the earth’s atmosphere and space are escalating, requiring urgent redressal.

Orbital debris, or space junk, refers to defunct satellites, spent rocket stages, and pieces of satellites produced when they break apart in low earth orbit (LEO). According to the European Space Agency, as of September 2024, there had been around 6,740 rocket launches since 1957 that placed 19,590 satellites in orbit. Around 13,230 are still in space and of them 10,200 are still functional.

Since the space in earth’s orbit is a resource just like water bodies and land masses on the ground, the occupation of orbits by non-functional objects constitutes a form of pollution as well — with the added threat of risk magnification.