The ozone layer protects Earth's inhabitants from the sun's dangerous ultraviolet (UV) rays. When the "ozone hole" over Antarctica was discovered in 1985, the destruction of the ozone layer became a major global issue.
To avoid this global crisis, the Montreal Protocol was enacted in 1987, which resulted in a ban on a class of chemicals called chlorofluorocarbons (CFCs), which were used in aerosols and refrigeration.
But the annual number of rocket launches is increasing as the global space industry expands rapidly.
There were a record 180 launches globally in 2022, according to the science journal Nature.
Within 40 years, the ozone layer is on track to recover, but this progress could be undone by an increase in rocket launches expected during the same period, according to new research.
Researchers warn that this rapid growth of the rocket industry puts the damaged ozone layer's ongoing repair at risk.
According to new research, rocket launches pose a hazard to more ozone damage.
If we don't act now, a quickly expanding rocket industry might undo decades of work to save the ozone layer.
Rocket launches emit both gases and particulates. Contemporary rockets emit a variety of pollutants, including Reactive Chlorine, Black Carbon, and Nitrogen Oxides, among others.
These gases and particulates punch through the atmosphere, which can delay the recovery of the ozone layer.
These prevent the ozone layer from fully recovering and damage it as well.
For rocket propulsion, the launch industry today relies on four major fuel types:
Liquid Kerosene, Cryogenic, Hypergolic, and Solid.
Due to the combustion of these fuels, modern rockets create a suite of gaseous and particulate exhaust products, including nitrogen oxides, carbon dioxide, water vapor, black carbon, alumina, and reactive chloride. These products are known to destroy ozone.
Solid rocket fuel includes a substance that releases chlorine into the upper atmosphere and distroys ozone.
Because CFCs contain chlorine, they were banned.
Rocket fuel emissions are unregulated.
In the stratosphere, an upper level of the atmosphere that contains the protective ozone layer, emissions linger for much longer than lower down.
Even small amounts of an exhaust byproduct can be more harmful in the upper atmosphere than near the Earth's surface.
Rocket emissions in the upper atmosphere can harm the ozone layer but are not regulated.
Rockets hold an exciting promise of space exploration.
We need precise models of the effects emissions have on the atmosphere to assess emissions at the early stages of rocket development.
To protect the ozone layer, many communities – rocket launch providers, environmental regulators, atmospheric research scientists and government agencies — must collaborate internationally.