Greenhouse Gas Emissions Threaten Satellites

Context

Rising greenhouse gas emissions are creating an unexpected challenge for humanity’s use of space: the upper atmosphere’s cooling and contraction due to climate change is reducing its capacity to safely host satellites. This phenomenon, driven by increased carbon dioxide (CO₂) concentrations, threatens to amplify collision risks in low-Earth orbit (LEO) and could shrink the region’s satellite-carrying capacity by up to 66% by 2100 under high-emission scenarios.

Mechanism: How Greenhouse Gases Affect Satellite Orbits

Greenhouse gases like CO₂ absorb heat in the lower atmosphere but have the opposite effect in the upper atmosphere. In the thermosphere (125–620 miles above Earth), these gases radiate energy into space, causing cooling and contraction. This layer is critical for generating atmospheric drag, which pulls defunct satellites and debris downward to burn up. With a thinner thermosphere, drag diminishes, leaving debris to linger longer and increasing collision risks.

• Current state: Over 11,900 satellites orbit Earth, with millions of debris fragments.
• Impact of reduced drag: Debris lifetimes in LEO could extend significantly, crowding orbital pathways. For example, under high emissions, the thermosphere’s density could drop by 30–40% by 2100, reducing its ability to naturally clear space junk.

Projected Decline in Satellite-Carrying Capacity

A 2025 MIT-led study in Nature Sustainability modeled CO₂’s impact on LEO’s capacity, revealing alarming trends:

This decline stems from:

1. Prolonged debris presence: Less drag extends debris lifetimes, increasing collision probability.
2. Rising satellite launches: Over 100,000 satellites are expected by 2030, intensifying congestion.

Risks of Unchecked Orbital Congestion

1. Kessler Syndrome

A chain reaction of collision-causing LEO-use would come into effect where debris caused by one collision triggers others. This scenario becomes increasingly likely as orbital density increases, a situation for which the theory was first propounded in 1978. SpaceX alone executed 50,000 collision avoidance maneuvers in the first six months of 2024, which is a testament to the operational burden. 

2. Economic and Operational Challenges

• • Cost of debris removal: Active removal missions cost tens of millions per operation. 
  • Regulatory gaps: While the U.S. mandates satellite deorbiting within five years of mission end, enforcement globally is patchy.

Mitigation Strategies

1. Active Debris Removal (ADR)

• • Technology: Deploying robotic spacecraft or lasers to capture and deorbit debris.
  • Cost barriers: Current ADR methods are prohibitively expensive, requiring international funding partnerships.

2. Sustainable Satellite Design

• • Mandatory deorbit systems: Rules like the FCC’s 2022 rule on satellites must be enforced, allowing only minor post-mission disposal. 
  • Reusable satellites: Longer operating lifetimes will help lower launch frequencies. 

3. Climate-Driven Space Governance

• • Emission controls: Link international sustainability principles concerning outer space to their corresponding climate agreements, since atmospheric alterations directly influence orbital safety.
  • Collaborative international frameworks should be broadened like the UN’s Space2030 Agenda to address capacity limits and debris management.

Broader Environmental Impacts of Space Activities

Beyond orbital crowding, rocket launches and satellite reentries contribute to atmospheric pollution:

• Aluminum oxides: Particles from burning satellites persist in the upper atmosphere for centuries, potentially altering ozone chemistry.
• Methane monitoring: Initiatives like NASA’s EMIT mission use satellites to track emissions but face risks from the same orbital challenges they aim to mitigate.

Conclusion: A Call for Integrated Policies

The intersection of climate change and space sustainability demands urgent, coordinated action. Reducing greenhouse gas emissions remains critical to preserving the thermosphere’s debris-clearing capacity, while stricter space traffic management and ADR investments can avert a Kessler Syndrome scenario. 

Source: The Hindu

UPSC Mains Practice Question

Q. Greenhouse gas emissions are not only contributing to climate change on Earth but also posing a threat to satellites and space infrastructure. Discuss the impact of greenhouse gas emissions on the Earth’s upper atmosphere and its consequences for satellite operations. Suggest measures to mitigate these effects. (250 words)

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