Why satellite space junk may be bad news for the environment

Sub: Sci

Sec: Space sector

Context:

With the rapid increase in satellite launches, concerns are growing about the environmental impact of these spacecraft, particularly at the end of their lifecycle.

Rising Numbers of Satellites

Over 10,000 active satellites are currently orbiting Earth.
By the 2030s, this number is expected to exceed 100,000, and could rise to 500,000 in the following decades.
Most satellites burn up during re-entry, releasing pollutants into the upper atmosphere.

Pollution from Satellite Re-entry:

10% of aerosol particles in the stratosphere contain metals like aluminum from disintegrated satellites and rocket stages.
Emissions of aluminum and nitrogen oxides from satellite reentry increased from 3.3 billion grams (2020) to 5.6 billion grams (2022).
Rocket launches also release pollutants such as:
- Black carbon
- Nitrogen oxides, carbon monoxide
- Aluminum oxide
- Chlorine gases

Impact of Satellite Pollution on the Atmosphere

Ozone Layer Threat:
- The ozone layer protects life by absorbing up to 99% of UV rays from the Sun.
- Pollutants like aluminum oxide from satellites act as catalysts for ozone depletion, reversing progress made under the Montreal Protocol (1987) that banned harmful chemicals like
Atmospheric Chemistry Disruption:
- Soot from rocket engines: Absorbs solar energy, warming the atmosphere.
- Metals like copper: Released from spacecraft wiring, catalyze atmospheric reactions, including the formation of cloud-seeding particles.
Ripple Effects:
- Changes in atmospheric chemistry can disrupt Earth’s delicate balance, potentially causing widespread environmental and ecological chaos.

Global Initiatives to Address Space Debris

Space debris is a growing concern due to its potential to harm operational satellites, spacecraft, and future missions. Various organizations and countries are working on initiatives to mitigate, manage, and remove space debris.

International Guidelines and Agreements:

United Nations Office for Outer Space Affairs (UNOOSA)

Guidelines for Long-term Sustainability of Outer Space Activities (2019):
- Encourages nations to design satellites with de-orbiting mechanisms.
- Promotes the prevention of debris generation during space missions.

Inter-Agency Space Debris Coordination Committee (IADC)

A global forum of space agencies including NASA, ESA, and others.
Develops best practices for debris mitigation such as:
- Limiting post-mission orbital lifetimes.
- Minimizing debris creation during launches and operations.

Liability Convention (1972)

Holds states responsible for damage caused by their space objects, motivating better debris management.

Active Debris Removal (ADR) Projects:

Remove DEBRIS (ESA and University of Surrey):
- A demonstration mission testing technologies like:
  - Net capture for debris collection.
  - Harpoons to grab large objects.
  - Drag sails to accelerate de-orbiting.

ClearSpace-1 (ESA):
- Planned mission to capture and deorbit a defunct satellite using robotic arms.
Astroscale (Japan):
- ELSA-d Mission: Tests magnetic docking and capture systems for deorbiting debris.
China’s SJ-21 Satellite:
- Demonstrated the capability to relocate large debris into graveyard orbits.

Source: IE