Over the past seven years, there have been an increasing number of deployments of co-called “megaconstellation” satellite systems, far outstripping the number of satellites orbiting the earth that had been launched over the previous 60 years.
Megaconstellations are made up of hundreds or even thousands of satellites in low earth orbit. The largest of these is SpaceX’s internet-providing Starlink system which already has about 12,000 satellites in orbit with many more to come. The rockets launching these satellites use a kerosene-based fuel, which releases soot particles into the upper layers of the atmosphere. Soot from Earth-bound sources like cars and power plants is effectively washed out of the atmosphere by rainfall. Soot from rocket launches lingers in the upper atmosphere for years.
The effects of this upper atmosphere pollution are not well understood. They may have a mild cooling effect by decreasing the amount of sunlight reaching the Earth’s surface. But they may also have various negative environmental impacts. Estimates are that the amount of soot released into the upper atmosphere from satellite launches over the next 3 years will be comparable to what is emitted by all the passenger cars in the United Kingdom over that period.
Rocket launches are a unique source of pollution that injects harmful chemicals directly into the upper atmosphere and contaminates the Earth’s last remaining relatively pristine environment. So far, there has been little or no attention paid to this issue but it will ultimately be everyone’s problem.
