Space Debris: The Hidden Danger of Orbit
By Mukul
Cosmofluencer (Season 04)
Introduction
Space debris, often referred to as space junk, poses a significant and rapidly growing threat to satellite operations, crewed missions, and the sustainability of Earth’s orbital environment. As humanity’s reliance on space infrastructure increases, understanding the intricacies of space debris and its implications becomes critical.
Definition and Types of Space Debris
Space debris consists of defunct human-made objects in orbit around Earth that no longer serve a functional purpose. The types of space debris include:
- Defunct satellites: These are non-operational spacecraft that are left in orbit after their mission has ended.
- Spent rocket stages: The remnants of rocket stages that have completed their functions often remain in space and contribute to significant debris count.
- Mission-Related debris: This category includes various items, such as tools, lens covers, and other materials accidentally released during missions.
- Fragmentation debris: small pieces resulting from the breakup of operational satellites or collisions between debris objects.
The Current State of Space Debris
As of recent estimates, there are over 35000 tracked objects in orbit, with a staggering count of around 130 million pieces that are too small to be tracked. This situation is primarily exacerbated by the increasing number of satellite launches and operational satellites currently in orbit. Space debris is characterised by a broad size range, from large (more than 10 cm) to tiny (millimetres to centimetres) paint flecks, all posing collision risks to functional spacecraft and critical infrastructure such as the International Space Station (ISS).
Risks and Challenges Posed by Space Debris
The risks associated with space debris are multifaceted, like:
- Collision hazards: Even small pieces of debris can travel at a speed of 17,000 miles per hour, and at such velocity, even a tiny fragment can cause massive damage to operational satellites, potentially leading to mission failures.
- Cascading collisions: The phenomenon known as “Kessler syndrome” describes a self-sustaining cascade of collisions between debris and operational satellites, which could exponentially increase the amount of space debris, rendering certain orbits unusable.
- Threats to human life: Astronauts aboard the ISS are at risk from space debris. In emergencies, they must evacuate to lifeboats in case of a predicted collision with larger debris.
- Economic implications: increased risks from space debris also impose economic challenges; for example, operators may face significant financial losses if their satellites are disabled or destroyed by debris impacts.
Mitigation Strategies
Efforts to mitigate space debris centre on two main strategies:
- Device design: Satellites are being designed for controlled deorbiting at the end of their mission and for preventing fragment generation during their mission.
- Active Debris Removal (ADR): Various innovations are under development, including robotic systems equipped with nets and harpoons to capture and remove space debris.
- Robotic Systems: Missions involving robotic arms or nets can capture larger debris pieces and then either deorbit them or place them in safe orbits.
- Laser Systems: Emerging proposals suggest using ground-based or space-based lasers to nudge smaller debris out of orbit, potentially altering their trajectories so they re-enter the atmosphere without causing harm.
- International Guidelines: Establishing international guidelines, such as the UN Space Debris Mitigation Guidelines, provides a framework for best practices that nations can adopt. These guidelines recommend measures like minimising debris released during normal operations and identifying unintentional releases that need to be addressed.
Conclusion
As the presence of debris increases, the urgency for comprehensive policies and collective international action to sustain it also increases, and addressing the hidden danger of space debris will require innovative solutions, stringent regulations, and heightened awareness.
References
- Natural History Museum | What is space junk and why is it a problem?
- UNU Institute for Environment and Human Security | 5 Things You Should Know about Space Debris
- European Space Agency | How many space debris objects are currently in orbit?
- Astroscale | Space debris – a historical problem
- European Space Agency | ESA Space Environment Report 2024