Context: As the number of satellites in the Earth’s orbit are increasing, there are mounting concerns over the pollution caused by these satellites in the upper atmosphere.
Relevance of the topic: Prelims- Satellite Pollution, Impacts of satellite pollution
Surge in Satellite Numbers
Currently, over 10,000 active satellites orbit around the Earth. This number is estimated to rise to more than 100,000 by the 2030s, and possibly half a million in the subsequent decades.
Pollution caused by Satellites:
- Pollution due to satellite launches: Emissions from rocket launches contribute to pollutants, which include:
- Black carbon
- Nitrogen oxides
- Carbon monoxide
- Aluminium oxide
- Chlorine gas
- Pollution on re-entering Earth’s atmosphere: Most satellites at the end of their life-cycle, re-enter Earth’s atmosphere, where they burn-up due to intense friction. In this process, they release various pollutants into the stratosphere, like- aluminium, nitrogen oxides, and other harmful chemicals into the stratosphere.
- As per the recent data from NOAA, 10% of the aerosol particles in the stratosphere contain aluminium and other metals that have originated from the burn-up of satellites, and rocket stages during satellite re-entry.
- As per a recent study, there has been a significant rise in aluminium and nitrogen oxide emissions, increasing from 3.3 billion grams in 2020 to 5.6 billion grams in 2022.
Impact of Satellite Pollution:
- Threat to Ozone Layer: Ozone layer in Earth’s stratosphere absorbs up to 99% of ultraviolet rays from the Sun. But pollutants from burnt-up spacecraft are likely already harming it. E.g.,
- Aluminium oxide is a known catalyst for ozone depletion.
- Threat to Earth’s Ecosystem: The spacecraft pollutants might impact the atmospheric composition, as,
- Warming of atmosphere: Soot emitted from rocket engines absorbs solar energy, which can warm the atmosphere.
- Chemical Reactions: Copper and other metals released during the incineration of spacecraft wiring and alloys are powerful catalysts which can initiate chemical reactions in the atmosphere.
- Cloud Formation: The metals emitted during satellite incineration can act as seeds for cloud formation, and potentially alter weather patterns.
These miniscule changes in Earth’s atmosphere can trigger massive chaos on the planet.
Way Forward:
- Improved satellite design by utilising materials that produce fewer harmful by-products upon re-entry.
- Encouraging minimal rocket launches by maximising the number of satellites in one launch.
- Encouraging the development of technologies for controlled satellite disposal or in-orbit recycling.