Each year, thousands of satellites at the end of their life fall toward Earth, burning up in the atmosphere. In their wake, they leave a trail of chemicals behind that depletes the ozone layer over time.
This is all part of the plan: ‘Design for Demise’ is a standard concept for making satellites that break apart upon reentry, limiting the threat of space junk to other satellites and the Earth below. But as humans launch (and burn up) more satellites than ever before, the environmental consequences are increasing.
Now, researchers from European company MaiaSpace, a subsidiary of ArianeGroup that builds launch vehicles, are flipping the idea on its head: They argue a ‘design for non-demise’ approach could help protect the atmosphere from our space robots.
In a recent paper, MaiaSpace staffers Antoinette Ott and Christophe Bonnal argue that a new end-of-life strategy for satellites could reduce negative environmental impacts. Their suggested solution comes with its own challenges, notably the risk of debris falling to the Earth, but finding the right path forward will depend on weighing the dangers of both strategies.
Chemical junk
Pollution from reentering satellites has become an increasing threat to the upper atmosphere, particularly the ozone layer in the stratosphere that protects the Earth from ultraviolet radiation. When satellites burn up during reentry, they produce tiny particles of aluminum oxide; these oxides catalyze destructive reactions between ozone and atmospheric chlorine that depletes the natural radiation shield.
A 2024 study found that a typical 550-pound (250-kilogram) satellite, estimated to be 30% aluminum by mass, could generate about 66 pounds (30 kilograms) of aluminum oxide nanoparticles when it burns up in the atmosphere. The study showed that a growing number of reentering satellites contributed to a shocking eightfold increase in harmful oxides in Earth’s atmosphere over six years.
Keeping it together
The new research suggests a ‘design for non-demise’ approach might be the better option. Engineers would design satellites capable of surviving the superheated plunge through Earth’s atmosphere. The authors of the paper suggest that the satellites would undergo a controlled reentry maneuver to minimize the risk of falling space debris on inhabited areas on the ground.
If a non-demise approach becomes the norm, it’s likely to mean higher costs for satellite operators. Their spacecraft would need to be hefty enough to survive reentry, and likely require propulsion systems and fuel to ensure that the satellites land somewhere deep in the Pacific Ocean, far from land or people.
“Space object designing now face a question: should a vehicle be engineered to burn up completely, implying that surviving debris might increase casualty risk, or should it aim to minimize particle and gas emissions into the atmosphere, thereby limiting long-term environmental damage?” the researchers wrote in the paper.
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