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Space Junk
Context:
The increasing number of satellites and space debris orbiting Earth is raising significant environmental concerns.
According to NASA, more than 9000 tonnes of space junk is currently orbiting Earth including 30,000 pieces of at least 10 cm long travelling at orbital velocity. Even a small piece of junk could destroy a satellite or hit an astronaut doing a spacewalk. The Global space economy is set to reach $ 1.8 trillion by 2035 from $ 630 billion in 2023.
What is Space Junk?
- Space junk, also known as orbital debris, refers to defunct satellites, spent rocket stages, and fragments from disintegration, erosion, and collisions that orbit Earth.
- Since the dawn of the space age in the 1950s, humans have launched thousands of rockets and satellites, leaving behind a growing amount of debris in space.
- It includes large objects like dead satellites and rocket stages, as well as smaller fragments like paint flecks, nuts, bolts, and even tiny pieces of metal.
- These objects can travel at speeds of up to 28,000 kilometres per hour, making them potential hazards for operational satellites, space stations, and spacecraft.
The Growing Problem:
- With over 10,000 active satellites currently in orbit, this number is expected to rise to more than 100,000 by the 2030s.
- As satellites reach the end of their life cycles, they burn up upon re-entry into Earth’s atmosphere, leaving pollutants in the upper atmosphere.
- Research by Daniel Murphy (NOAA) and others found that 10% of aerosol particles in the stratosphere contain aluminium and other metals from burned-up satellites and rocket stages.
- The emissions of aluminium and nitrogen oxides from satellite reentries increased significantly from 3.3 billion grams in 2020 to 5.6 billion grams in 2022.
- Research by Daniel Murphy (NOAA) and others found that 10% of aerosol particles in the stratosphere contain aluminium and other metals from burned-up satellites and rocket stages.
- Rocket launches also contribute to pollutants such as black carbon, nitrogen oxides, carbon monoxide, aluminium oxide, and chlorine gases.
Environmental Impact:
- Impact on the Ozone Layer: The pollutants from burnt-up satellites and rocket stages can have far-reaching effects.
- Aluminium oxide, a byproduct of satellite incineration, is a known catalyst for ozone depletion. This could undermine the progress made by the Montreal Protocol of 1987, which successfully banned ozone-depleting substances like chlorofluorocarbons (CFCs).
- Potential Atmospheric Chemistry Changes: Soot from rocket engines absorbs solar energy, potentially warming the atmosphere. Metals like copper, released from spacecraft wiring, may act as catalysts for atmospheric chemical reactions, possibly influencing cloud formation.
Risks and Consequences:
- Collision Threat: High-speed collisions can damage or destroy operational satellites, leading to loss of communication, navigation, and weather forecasting capabilities.
- Excessive debris creates unusable regions and leads to the ‘Kessler syndrome’, creating more debris due to cascading collisions.
- Space Station Safety: The International Space Station (ISS) has had to perform numerous manoeuvres to avoid potential collisions with space debris.
- Environmental Impact: The disintegration of satellites and rocket stages can release harmful pollutants into the upper atmosphere, potentially affecting the ozone layer and climate.
Efforts to Mitigate the Problem:
- Active Debris Removal (ADR): Concepts and missions are being developed to capture and remove large pieces of debris from orbit.
- Better Satellite Design: Designing satellites with end-of-life disposal plans, such as deorbiting mechanisms, to ensure they do not contribute to space junk.
- International Collaboration: Global cooperation is essential to develop and implement guidelines and technologies to mitigate space debris.
Initiatives Taken:
- The Space Debris Mitigation Guidelines 2002, which were approved by the United States in 2007 outline methods to limit accidental collisions, break-ups during operations, intentional destruction, and post-mission break-ups.
- ESA’s ‘Zero Debris’ Charter: The European Space Agency has adopted a ‘Zero Debris’ charter, aiming for zero space debris by 2030 and advocating for debris mitigation measures.
- Japan’s CRD2 Project: Japan’s Aerospace Exploration Agency (JAXA) is working on the Commercial Removal of Debris Demonstration project, partnering with private company Astroscale to assess and remove debris from orbit.
- India’s Initiatives: Include Debris-Free Space Missions (DFSM) Initiative, System for Safe and Sustainable Operations Management (IS 4 OM), and Project NETRA.
