The global space industry is expanding rapidly, with thousands of new satellites expected to enter orbit in the coming years.
These spacecraft will support a wide range of activities, including internet services, Earth observation, scientific research, and even space tourism.
While this growth promises many benefits, scientists are becoming increasingly concerned about its environmental impact.
A new study suggests that rocket launches and the reentry of old satellites and rocket debris may be harming Earth’s ozone layer and contributing to global warming.
For decades, emissions from spaceflight were considered too small to significantly affect the environment because the number of launches was relatively low. However, the situation is changing quickly.
Thousands of additional spacecraft are expected to be launched into low-Earth orbit, causing emissions from the space industry to rise dramatically.
To better understand the potential effects, researchers analyzed every rocket launch and atmospheric reentry that occurred in 2022.
The study examined emissions from 186 rocket launches and 472 objects that reentered Earth’s atmosphere during that year. These reentering objects included old satellites and discarded rocket components with a combined mass of nearly 5,000 tons.
The researchers used computer simulations to track each rocket’s flight path and calculate the pollutants released at different altitudes. They also estimated the emissions produced when spacecraft and debris burned up during reentry.
Importantly, the team included chemical reactions that occur inside rocket exhaust plumes. These reactions can change the composition of emissions and affect their environmental impact.
Using an advanced atmospheric chemistry model, the scientists then examined how these pollutants influence the ozone layer and Earth’s climate.
The results showed that both rocket launches and atmospheric reentries contribute to ozone depletion and warming. Surprisingly, emissions from reentering spacecraft played a particularly important role in damaging the ozone layer.
One of the main culprits appears to be nitrogen oxides released during reentry. These chemicals can trigger reactions that destroy ozone, the protective layer in the upper atmosphere that shields life on Earth from harmful ultraviolet radiation.
The study also found that the type of rocket fuel matters.
Solid rocket fuels, which are used in some large rocket boosters, were associated with the greatest ozone damage relative to the amount of fuel burned. Meanwhile, rockets powered by kerosene-based fuels contributed the most to global warming.
The researchers noted that including the chemistry of rocket exhaust plumes reduced some earlier estimates of environmental damage. This suggests that future studies need to carefully account for these chemical processes to improve accuracy.
Although the current impact of spaceflight emissions remains relatively small compared with many other human activities, scientists warn that the industry’s rapid expansion could change that picture in the future.
The researchers say more studies are urgently needed to understand the long-term effects of rocket emissions and spacecraft reentries.
As humanity launches more satellites and explores space on a larger scale, understanding and managing these environmental impacts may become an important part of protecting Earth’s atmosphere.
