INTRODUCTION

• As humanity extends its reach beyond Earth, a growing concern emerges, space debris. These are man-made objects, like defunct satellites and leftover rocket parts, that clutter Earth's orbit and pose a significant risk to space exploration.

CURRENT STATS BY EUROPEAN SPACE AGENCY:

• 36500 space debris objects greater than 10 cm.

• 1 million space debris objects from greater than 1 cm to 10 cm.

• 130 million space debris objects from greater than 1 mm to 1 cm.

REASONS:

• Defunct satellites:  

• These are satellites that have reached the end of their operational life and no longer function.  

• For instance, commercial satellites typically only last around 15 years due to the harsh space environment.

• Rocket stages:  

• After launching a spacecraft, leftover rocket bodies and boosters are often placed in orbit. 

• These can collide with other objects or break up over time.

• Missing equipment:  

• During spacewalks, astronauts might accidentally drop tools or other objects, which become part of the debris.

• Collisions:  

• Even accidental collisions between operational satellites or debris can be catastrophic. 

• The resulting high-speed smashup can create thousands of new pieces of debris. 

• As an example, the 2009 collision between an operational US Iridium satellite and a defunct Russian Cosmos satellite created over 2,000 pieces of trackable debris.

• Anti-satellite weapons tests: 

•  Though less frequent, some countries have conducted tests using missiles to destroy satellites.  

• These tests create a significant amount of debris, as seen in the destruction of a Chinese weather satellite in 2007 which resulted in thousands of new debris pieces.

What risks does space junk pose to space exploration?

• Collisions: 

• Due to their high speeds (up to 18,000 mph!), even small pieces of debris can inflict serious damage upon impact.  

• A collision with a critical component on a spacecraft could cripple its functionality or even destroy it entirely. 

• This risk is especially concerning in regions with high debris concentration, like Low Earth Orbit (LEO).

• Disruptions and Delays:  

• The constant threat of collisions necessitates complex manoeuvres for operational spacecraft. 

• They frequently need to dodge debris, requiring additional fuel and potentially delaying missions or scientific observations.

• Cascading Kessler Syndrome:  

• Kessler Syndrome is a theoretical scenario where Earth's orbit becomes so crowded with debris and objects that satellites can no longer be used in certain areas.

• A collision between large objects could create a chain reaction, shattering them into countless new debris fragments. 

• This would exponentially increase the debris population in orbit, making space travel incredibly hazardous, if not impossible.

• Threat to Astronauts: 

• While space stations like the International Space Station (ISS) are shielded, a significant debris strike could still be dangerous for astronauts on board. 

• Additionally, debris poses a risk to spacecraft during Extravehicular Activities (EVAs) or spacewalks.

• Threat to Marine Life:

• Large objects falling into oceans, with 70% of Earth's surface covered by water, pose threats to marine life and contribute to pollution.

• Reduction of Orbital Slots:

• The accumulation of space debris in specific orbital regions can limit the availability of desirable orbital slots for future missions.

• Increases costs

• Space companies will increasingly rely on stronger and robust materials to withstand collisions, potentially leading to launch delays or rescheduling as a precaution against debris threats. Consequently, Increases the cost of space missions.

• The potential damage and loss caused by even small debris pose significant risks to missions.

• A collision has the capacity to cripple or completely destroy a satellite, necessitating costly replacements and resulting in mission failures.

POSSIBLE SOLUTIONS:

• Passivation:  

• This involves depleting the energy sources (fuel, batteries) of defunct satellites at the end of their mission and reduces the risk of explosions creating new debris.  

• For example, ESA's Clean Space initiative promotes passivation techniques for their satellites 

• Limiting debris generation during launches:  

• This involves designing rockets to minimise leftover stages and debris from separation events.  

• For instance, SpaceX's Falcon 9 rocket is partially reusable,  reducing the number of stages left in orbit.

• Operational procedures:  

• Space agencies and satellite operators can collaborate on manoeuvres to avoid collisions between operational spacecraft and tracked debris.  

• For example, the  US Department of Defense's Joint Space Operations Center (JSpOC) tracks debris and issues collision warnings to satellite operators.

• Docking and deorbit: 

• This concept involves sending a servicing spacecraft to capture a defunct satellite and deorbit it  safely into Earth's atmosphere for burn-up.

• Example: ClearSpace-One, a Swiss start-up,  is developing a mission to capture a defunct satellite with a robotic arm.

• Harpoons or nets:  

• These technologies involve using projectiles or tethered nets to snag debris objects and deorbit them.  

• Example: The RemoveDebris project by a consortium of European companies is a demonstration mission testing a harpoon technology.

• Japan’s JAXA partnered with Nitto Seimo, a company that specialises in fishing equipment, to develop the net. 

• The net was made of a strong, lightweight material and was designed to be unfolded in space.

• Launched from a satellite, the net would use electricity to create a magnetic field, attracting debris. 

• Eventually, the net and debris would be de-orbited and burn up in the atmosphere

INDIA’S ROLE IN MITIGATING SPACE DEBRIS

• Space Situational Awareness (SSA): 

• ISRO has established a network of radars and telescopes to track space objects and assess collision risks for Indian satellites.

• Collision Avoidance Manoeuvres (CAMs):  

• ISRO has successfully performed collision avoidance manoeuvres to safeguard its operational spacecraft from debris threats.

• IS4OM - Collision Risk Monitoring System:  

• ISRO's System for Safe and Sustainable Operations Management (IS4OM)  continuously monitors objects in orbit to identify and mitigate potential collision threats.

• Membership in Key Organisations: 

• India is a member of the Inter-Agency Space Debris Coordination Committee (IADC), the  International Astronautical Federation (IAF) Space Debris Working Group, and the United Nations Committee on the Peaceful Uses of Outer Space (COPUOS).

• Advocacy for Stronger Mitigation Measures: 

• ISRO, the Indian Space Research Organisation, emphasises the importance of stricter space debris mitigation guidelines to ensure sustainable space activities.

• ISRO POEM-3:

• ISRO's PSLV-C58/XPoSat mission left zero debris in Earth's orbit by transforming the last stage into the PSLV Orbital Experimental Module-3 (POEM-3) , a kind of orbital station, which safely re-entered the atmosphere after the mission instead of floating in orbit.

• The PSLV has four stages. After using up their fuel, the first three stages fall into the ocean.

• The fourth stage, known as PS4, usually becomes space debris after launching the satellite.

• However, for the PSLV-C53 mission, the PS4 stage will have a new role as a stable platform for experiments. The PS4 will orbit the Earth while staying stable.

• This new approach turns part of the PSLV into a laboratory for space research.

• POEM has its own Navigation Guidance and Control (NGC) system. This system acts as the platform’s brain, ensuring it stays in a stable position accurately.

• POEM is equipped with payloads and obtains its power from solar panels installed around the PS4 tank, supplemented by a lithium-ion battery.

• For navigation, it utilises four sun sensors, a magnetometer, gyroscopes, and the NavIC system.

• Additionally, it features specialised control thrusters powered by stored helium gas and is equipped with a telecommand capability for receiving instructions.

• ‘Project NETRA’ 

• It is an early warning system in space to detect debris and other hazards to Indian satellites.

• Under NETRA, the ISRO plans to put up many observational facilities: connected radars, telescopes, data processing units and a control centre.

• It can track objects as small as 10 cm, up to a range of 3,400 km and equal to a space orbit of around 2,000 km.

CONCLUSION

Addressing the increasing threat of space debris demands international collaboration, multifaceted mitigation strategies, and public engagement to ensure sustainable solutions for the future of space exploration and safety.

Tags:
Polity

Keywords:
SPACE SPACE EXPLORATION NASA ISRO