04-December-2024-Editorial

SPACE DEBRIS – GROWING PROBLEM

The increasing number of satellites and space debris in Low Earth Orbit (LEO) has become a growing concern for space agencies worldwide. The rapid expansion of space activities, especially with private sector involvement, has raised alarms about the long-term sustainability of this crucial area.

In response to these concerns, international bodies such as the United Nations have stressed the need for urgent global collaboration to manage space traffic and mitigate the risks posed by debris.

What is Low Earth Orbit (LEO)?

Definition and Characteristics:

• Low Earth Orbit (LEO) is the region around Earth at altitudes between 180 km and 2,000 km.
• It is the closest orbit to Earth’s surface and is used extensively for various satellite operations, including the International Space Station (ISS).
• Orbital Speed: To stay in LEO, satellites must travel at approximately 7.8 kilometers per second. This high-speed balances Earth’s gravitational pull with centrifugal force, allowing the satellite to remain in orbit.
• Orbit Duration: Satellites in LEO take about 90 minutes to complete a full orbit around Earth.
• Stability: Satellites in LEO remain in orbit until external forces, such as atmospheric drag or orbital decay, affect their trajectory. Unlike objects exceeding escape velocity or those returning to Earth, satellites in LEO maintain their orbit for long periods unless acted upon by these forces.

Importance of LEO:

Satellite Applications:

• Earth Observation: LEO is ideal for satellites designed for Earth observation, as it allows them to capture high-resolution images and gather detailed data due to the proximity to the Earth’s surface.
• Communications and GPS: Many communication satellites and Global Positioning System (GPS) satellites operate in LEO, offering lower latency and faster transmission speeds compared to higher orbits.
• International Space Station (ISS): The ISS is located in LEO, enabling frequent crew exchanges and resupply missions, which is essential for human space exploration and scientific research.
• Cost Efficiency: Launching satellites into LEO is more affordable than sending them to higher orbits like Geostationary Orbit (GEO), as it requires less energy.

Challenges in LEO:

LEO Congestion and Space Debris:

• The rapid increase in the number of satellites in LEO, coupled with decommissioned satellites and spent rocket stages, has led to a significant rise in space debris.
• Current Statistics: Over 14,000 satellites, including 3,500 inactive ones, and approximately 120 million fragments of debris, are currently in LEO.
• Recent Incidents: Explosions of defunct satellites, like a Chinese rocket and a Russian satellite, have exacerbated the problem of space debris, heightening risks to active satellites and astronauts aboard the ISS.

Collision Risks:

• The growing density of satellites and debris in LEO increases the likelihood of collisions. Studies predict damages worth $556 million between 2024-2029 due to space debris, with a collision probability of 3.13%.
• There has been a 17% increase in close encounters per satellite in the past year, highlighting the growing risks in LEO.

Orbital Saturation:

• The expansion of satellite constellations, particularly by companies like SpaceX (with Starlink’s 6,764 satellites), has intensified competition for available orbital slots, creating a need for more effective regulation and international cooperation.

Management Challenges:

• Commercial Interests: Private companies such as SpaceX are often protective of satellite data, limiting transparency and complicating the tracking of both active satellites and debris.
• Lack of Standardization: Currently, collision avoidance methods are informal and inconsistent, leading to difficulties in developing universal protocols for satellite operations.
• Geopolitical Tensions: Nations are often unwilling to share satellite data due to security concerns, particularly regarding dual-use satellites (both military and civilian), making international cooperation challenging.
• Weaponization of LEO: Anti-satellite missile tests by countries like China, the USA, India, and Russia have generated significant debris, adding to the threat of space collisions. For example, China’s SC-19 test in 2007 resulted in over 3,000 trackable debris fragments.

Threats Posed by Space Debris:

Operational Risks:

• Space debris poses a major threat to operational satellites, as collisions with debris can damage or destroy functional spacecraft, disrupting essential services like communication and navigation.
• Reduction of Orbital Slots: The accumulation of debris limits available orbital slots, hindering future space missions and reducing the usable space around Earth.

Kessler Syndrome:

• Kessler Syndrome refers to a situation where the density of space debris becomes so high that the likelihood of collisions increases, leading to even more debris in a vicious cycle.
• Historical Example: In 2009, a defunct Russian satellite collided with an American weather satellite, generating thousands of pieces of debris, illustrating the dangers of space debris.
• This concept challenges the Big Sky Theory, which initially suggested that space’s vastness would prevent long-term problems with debris.

Initiatives to Address Space Debris:

India’s Efforts:

• ISRO’s System for Safe and Sustainable Operations Management (IS 4 OM): This system, launched in 2022, monitors potential collision risks in space and develops strategies for debris mitigation.
• Collision Avoidance Maneuvers: In 2022, ISRO successfully performed 21 maneuvers to avoid collisions between Indian satellites and space debris.
• Project NETRA: A space debris early-warning system developed by ISRO to protect Indian satellites from potential collisions.
• Centre for Space Debris Research: ISRO established this center to research space debris and develop mitigation strategies.

Global Efforts:

• Inter-Agency Space Debris Coordination Committee (IADC): An international body established in 1993 to coordinate space debris management efforts among spacefaring nations.
• COPUOS (United Nations Committee on the Peaceful Uses of Outer Space): COPUOS works on developing long-term guidelines for space sustainability, including debris mitigation.
• European Space Agency’s Clean Space Initiative: ESA promotes technologies to reduce debris creation and clean up existing space debris.

Way Forward:

Improved Monitoring and Coordination:

• Enhanced tracking systems and improved orbital models are necessary for more accurate debris detection and management.
• International Collaboration: As space traffic increases, it is crucial for spacefaring nations to collaborate on establishing systems for space traffic management, including creating automated “right-of-way” protocols.

Reducing Debris Generation:

• Reusable Rockets: Launching reusable rockets instead of one-time-use vehicles can significantly reduce new debris production.
• India’s Reusable Rocket (RHUMI-1): India’s recent launch of the RHUMI-1 hybrid rocket highlights the shift toward sustainable space missions.

Active Debris Removal:

• Various technologies, including harpoons, magnets, and lasers, are being explored to remove debris. For example, ISRO successfully deorbited the Megha Tropiques-1 satellite in 2023.
• Graveyard Orbits: Satellites nearing the end of their lifespan in geostationary orbit should be moved to a graveyard orbit beyond 36,000 km to minimize the creation of new debris.

International Guidelines Compliance:

• It is crucial for all spacefaring nations to adhere to international guidelines, such as those from the International Association for the Advancement of Space Safety (IADC), to ensure space activities remain sustainable.

Conclusion:

The growing issue of space debris in LEO presents significant challenges to satellite operations and the future of space exploration. To safeguard this vital region, global cooperation, improved monitoring, and innovative technologies are essential. With collective efforts and proper management strategies, the sustainability of space activities can be ensured for future generations.