CONTEXT – ISRO’s PSLV-C58/XPoSat mission created almost no debris in space. The final stage of the rocket, called POEM-3, was converted into an orbital station and safely re-entered the Earth’s atmosphere instead of lingering in orbit. ISRO also said it “passivated the stage,” meaning dumped its fuel, to avoid an explosion that could have flung small pieces of debris into orbit

POEM

• Developed by the Vikram Sarabhai Space Centre (VSSC) as a low-cost space platform.
• Uses the spent fourth stage of a PSLV rocket as an orbital platform.
• Functionality and Features:
  • Powered by solar panels and a lithium-ion battery.
  • Equipped with a navigation, guidance, and control (NGC) system for altitude stabilization.
  • Includes helium control thrusters and sensors (Sun sensors, magnetometer, gyroscopes) for navigation.
  • Has a telecommand system for ground station communication.
• Previous Demonstrations:
  • First used in the PSLV-C53 mission in June 2022 for in-orbit scientific experiments.
  • Earlier demonstrated in the PSLV C-44 mission in 2019, showcasing reuse by moving to a higher orbit post-satellite deployment

SIGNIFICANCE

• Low Earth Orbit (LEO) is a critical zone extending from 100 km to 2000 km above Earth, hosting vital satellites for intelligence, communication, and navigation.
• The increasing number of satellites in LEO has led to a serious issue: space debris, including defunct satellites, spacecraft remnants, and debris from anti-satellite tests, poses significant risks due to high speeds of up to 27,000 km/hr.
• In 2022 alone, 2,533 objects were launched into space across 179 missions, as reported by ISRO’s Space Situational Assessment Report.
• Additionally, there are approximately 7,000 operational satellites in various orbits around Earth, alongside millions of space debris pieces.
• The U.S. Space Command plays a crucial role by tracking and cataloging debris larger than 10 cm in LEO and 0.3-1 m in GEO, aiding in space asset protection

ACHIEVEMENTS OF POEM-3:

• Launched from the Satish Dhawan Space Centre in Sriharikota on January 1 2024
• After deploying XPoSat in a 650 km orbit, POEM-3 (fourth stage) was lowered to a 350 km circular orbit for experiments.The closer a satellite is to Earth, the more drag it faces and the more energy it requires to stay in orbit
• POEM-3 featured nine payloads (agencies associated – VSSC and Bellatrix Aerospace Pvt Ltd, TakeMe2Space, Inspecity Space Labs Pvt Ltd., Dhruva Space, LBS Institute of Technology, KJ Somaiya Institute of Technology, and ISRO’s Physics Research Laboratory, Ahmedabad)
• Completed 400 orbits around the earth by its 25th day during when payloads were operationalised to perform their experiments
• ARKA200, RUDRA, and LEAP-TD completed their respective experiments while the data from WeSAT, RSEM, and DEX were collected after every orbit for further analysis on the ground
• Two fuel cells from VSSC demonstrated their ability to generate power
• Completed all payload objectives by January 27, 2024
• For two months, POEM-3 prepared for its re-entry while ISRO tracked it with its Telemetry, Tracking and Command Network stations in Bengaluru, Lucknow, Mauritius, Sriharikota, Port Blair, Thiruvananthapuram, Brunei, and Biak (Indonesia) and the Multi-Object Tracking Radar (MOTR) at Sriharikota
• On March 21, POEM-3 re-entered the earth’s atmosphere, meeting its fiery end leaving behind zero debris

HOW ARE AGENCIES DEALING WITH DEBRIS?

• Incident Response: Agencies respond to space debris incidents promptly, such as the recent case of a battery pallet damaging a house in Florida on March 8.
• Increasing Debris: With more satellites launched and anti-satellite tests conducted, the number of collisions and on-orbit breakup events leading to smaller fragments has risen significantly.
• Projected Debris Numbers: Estimates from ISRO suggest that by 2030, there could be around 60,000 space objects (debris or functional equipment) larger than 10 cm in Low Earth Orbit (LEO).
• Risk of Collisions: Accumulation of debris can create hazardous regions in orbit, increasing the risk of cascading collisions that generate even more, smaller debris pieces.
• Legal Framework: While there are no specific international laws for LEO debris, most spacefaring nations follow the Space Debris Mitigation Guidelines from 2002, endorsed by the U.N. in 2007 through the Inter-Agency Space Debris Coordination Committee (IADC)

BENEFITS FOR INDIA

• Space Sustainability: By converting the final stage of the PSLV rocket into an orbital station and safely re-entering it into Earth’s atmosphere, ISRO has demonstrated a commitment to space sustainability. This approach minimizes space debris, reducing the risk of collisions and safeguarding operational satellites in Low Earth Orbit (LEO). India’s space sector stands to benefit from a cleaner orbital environment, ensuring the longevity and reliability of its space assets.
• Technological Advancement: The development and utilization of POEM-3 as a low-cost space platform showcase India’s technological prowess. Technologies such as solar panels, lithium-ion batteries, navigation systems, and telecommand systems used in POEM-3 contribute to India’s capabilities in space exploration and satellite operations. This technological advancement can be leveraged for future space missions, satellite deployments, and scientific endeavors.
• International Collaboration: Collaboration with various agencies and institutions for payload deployment and scientific experiments onboard POEM-3 reflects India’s collaborative approach in space exploration. This cooperation enhances India’s standing in the global space community, fostering partnerships for joint research, technology exchange, and knowledge sharing.
• Scientific Research and Innovation: The successful completion of experiments and data collection by payloads onboard POEM-3 signifies India’s commitment to scientific research and innovation in space. The insights gained from these experiments can contribute to advancements in diverse fields such as remote sensing, communication technology, Earth observation, and space exploration. This knowledge can be applied to address societal challenges and drive economic growth.
• Environmental Stewardship: By actively mitigating space debris through responsible space practices, India demonstrates its environmental stewardship in space activities. This aligns with global efforts to promote sustainable space exploration and minimize the impact of human activities on the space environment. India’s leadership in this regard enhances its reputation as a responsible space-faring nation.
• Strategic Importance: As space activities become increasingly integral to national security, communication, navigation, and disaster management, India’s advancements in space technology and debris mitigation contribute to its strategic capabilities. A cleaner orbital environment reduces vulnerabilities and ensures the resilience of critical space infrastructure, benefiting national security and societal well-being.
• Policy Influence: India’s adherence to space debris mitigation guidelines and its participation in international frameworks such as the Inter-Agency Space Debris Coordination Committee (IADC) demonstrate its commitment to responsible space governance. This involvement allows India to influence global policies, standards, and best practices in space debris management, shaping the future of space activities on a global scale.