ARE SATELLITES BURNING UP IN THE ATMOSPHERE BAD FOR THE ENVIRONMENT?

About 13,000 satellites currently orbit Earth, roughly 10,000 of which are operational. But that number is set to skyrocket, with a staggering 50,000 new satellites on track to join them by 2030.

- CLAUDINE BEST

The dramatic increase is due to the rise in internet-beaming mega-constellations of satellites, such as SpaceX's Starlink. Out of almost 8,000 satellites now in low Earth orbit (altitudes typically below 2,000km or 1,200 miles), nearly 6,500 are Starlink satellites. SpaceX already has the go-ahead to deploy 12,000 satellites and is seeking approval for 30,000 more. Meanwhile, other companies, including Amazon, are planning mega-constellations of their own.

The upshot: low Earth orbit is becoming increasingly cluttered. As well as raising the likelihood of collisions, there's mounting concern among scientists that mega-constellations could damage the critical layer of ozone that shields Earth from harmful UV radiation.