Why scientists are worried about re-entries of Musk's Starlink satellites
What's the story
The rapid expansion of SpaceX's Starlink satellite network has resulted in an increase in re-entries of retired satellites.
These re-entries, which are often seen as bright streaks in the night sky, are raising alarms among scientists over their environmental impact.
The main concern is the release of metallic vapors into the atmosphere during these re-entries, which could potentially harm the ozone layer.
Satellite retirement
Over 120 Starlink satellites re-entered Earth's atmosphere in January
In just January, over 120 Starlink satellites have re-entered Earth's atmosphere, with an average of four to five satellites burning up every day.
This surge is due to the mass retirement of the first-generation (Gen1) Starlink satellites.
Astronomer Jonathan McDowell says around 500 of these older models have already hit their end-of-life and are being replaced with newer ones.
Network update
SpaceX's satellite network refreshment plan
SpaceX currently has nearly 7,000 satellites in orbit to offer global internet coverage and plans to refresh its satellite network every five years.
While these re-entries are part of the company's strategy, they have sparked concerns over atmospheric pollution.
However, despite the worries, SpaceX insists its satellites are designed to fully burn up upon reentry, leaving no debris behind.
Ozone threat
Satellite debris found in aerosols above Alaska
A 2023 study found satellite debris in aerosols 60,000 feet above Alaska.
Scientists are especially worried about the release of aluminum oxides during these re-entries, as each Gen1 Starlink satellite releases around 30kg of this compound known to deplete the ozone layer.
Research shows these oxides rose eightfold between 2016 and 2022, prompting warnings that this could change atmospheric chemistry in unpredictable ways.
Disruption
Space debris: A potential disruptor for air travel
The problem of space debris goes beyond Starlink satellites. Studies indicate a 26% yearly chance of rocket parts returning to Earth.
Although the risks to flights are low, debris could disrupt air travel and cost airlines more due to uncontrolled re-entries.
Despite these environmental concerns, the higher re-entry rate also means a greater chance of seeing these fireballs in the night sky.