Physics fellow Dr Fionagh Thomson will explore the potential risks of decommissioning satellites in the atmosphere in a project funded by the UK Space Agency.
What happens to our satellites at the end of their working lives?
Thousands of satellites orbit the Earth at any given time. These spacecraft are constantly being taken out of commission to reduce space debris. Some fall to the Earth, where they land in the ‘spacecraft cemetery’ in the southern Pacific Ocean.
Others are burnt up in the atmosphere to avoid impact with humans on the ground. The environmental impact — if there is one — of burning the satellites is unclear.
It’s this unknown that Senior Research Fellow in the Department of Physics Dr Fionagh Thomson is researching in her UK Space Agency-funded project, along with co-investigator Professor Dan Cziczo of Purdue University, USA.
Her work will focus on retired satellites that undergo an ‘uncontrolled de-orbit.’ Once the spacecraft’s fuel is spent, gravity pulls them into the atmosphere where they burn up.
This means satellites need to be built to withstand leaving the atmosphere, but not coming back through it.
In February, Elon Musk announced that 100 of his Starlink satellites would be disposed of in this way.
Until recently, it hasn't been known — or it has been assumed — that this re-entry doesn’t cause harm to the environment.
Traditionally, the space industry and astrophysicists assumed any particles that are left in the upper atmosphere after the materials burn up are negligible.
One team of atmospheric researchers, meanwhile, recently identified metals found only in spacecrafts that might increase the surface area of ozone-depleting polar clouds.
Fionagh says there’s not enough rigorous evidence to make an informed conclusion. What’s more, she warns, relying on poor-quality findings is a path toward misinformation and ineffective policy.
Working with colleagues across industry and academia, Fionagh is mapping out what we know and don’t know about the impact of satellite re-entries. She is outlining the potential opportunities and barriers to reducing the number of satellites burning in the outer atmosphere.
This research will, in turn, inform the UK Space Agency’s approach to this important issue which is gathering significant global interest.
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