Impact of Greenhouse Gas Emissions on Satellite Sustainability

Sub: Sci

Sec: Space sector

Why in News

A recent study published in Nature Sustainability highlights that rising greenhouse gas (GHG) emissions could significantly reduce the number of satellites that can safely orbit Earth.

Effects of Greenhouse Gas Emissions on Earth’s Upper Atmosphere:

The upper atmosphere consists of the mesosphere (50-85 km) and thermosphere (85-600 km).
Increased greenhouse gases cause infrared radiation to be reflected into space, leading to atmospheric cooling and contraction.
This contraction reduces air density in orbital regions, affecting satellite drag.
Lower atmospheric density leads to reduced drag on space debris. Debris remains in orbit for extended periods, increasing the risk of collisions.
As the number of operational satellites increases, space congestion worsens, posing challenges for long-term sustainability.
MIT Cambridge, researchers assessed different emission scenarios, using year 2000 greenhouse gas levels as a baseline.
Under the highest emission scenario (Shared Socio-economic Pathway (SSP5-8.5)), the sustainable number of satellites in low Earth orbit (LEO) is projected to decrease by 50-66% by 2100.
The study observed a substantial decline in satellite deorbiting rates under moderate-to-high CO₂ emission scenarios.

Shared Socio-economic Pathway (SSP5-8.5):

SSP5-8.5 is one of the five Shared Socioeconomic Pathways (SSPs) used in climate modelling for the IPCC reports.
It represents a high-emissions, fossil-fuel-intensive scenario with rapid economic growth and technological advancements but little focus on sustainability.
Key Characteristics:
Severe Climate Impact:
- CO₂ concentration rises significantly, leading to a global temperature increase of 4-5°C by 2100.
- Increased frequency of extreme weather events, sea level rise, and biodiversity loss.
Fossil Fuel Dependency:
- Energy demand is met predominantly by coal, oil, and gas.
- Renewable energy adoption is minimal.