Satellite debris poses a serious threat to the atmosphere

Hundreds of defunct satellites fall through Earth's atmosphere every year, and the number is growing rapidly.

The space race is on with a massive constellation of satellites aimed at providing global broadband internet. However, this is having worrying consequences for the environment.

Hundreds of defunct satellites fall through the Earth's atmosphere every year. (Illustration: Getty Images)

According to statistics, there are currently about 10,000 satellites operating in orbit, of which two-thirds belong to SpaceX's Starlink. By the 2030s, this number is expected to reach 100,000 satellites.

The problem is that these satellites are designed to be 'disposable' – after a few years of operation they are sent down to low orbit and burn up in the atmosphere. Each satellite that disintegrates releases metals into the atmosphere.

"The number of satellite launches is increasing rapidly. The last two years have seen about 500 crashes per year, and that number could increase to 10,000 in the near future - equivalent to one crash per hour," said Daniel Murphy, an expert at the NOAA Chemical Sciences Laboratory.

Recent studies have found traces of more than 20 different metallic elements in the stratosphere , including niobium and hafnium - metals refined from ores to make heat-resistant alloys. Metals such as aluminum and copper are also present in amounts far exceeding natural levels.

More worryingly, satellite debris could have a negative impact on the ozone layer . Aluminum oxide - a product of satellite combustion - is known to be a catalyst for ozone depletion.

Scientists are rushing to fully assess the impact of this "satellite junk" . Expert José Ferreira, University of Southern California, suggests that environmental factors should be included in the design phase of space missions.

'We need to understand these impacts before we continue to launch more satellites,' Mr. Murphy stressed.