September 16, 2025
In the silent, airless expanse of low Earth orbit (LEO), a new kind of mission is underway. It is not about reaching further into the cosmos or peering deeper into the origins of the universe. Instead, it is an operation of critical maintenance, a necessary act of celestial housekeeping to secure humanity’s future in space. The Indian Space Research Organisation (ISRO), long celebrated for its cost-effective and ambitious satellite launches and interplanetary probes, is now spearheading a less glamorous but arguably more vital endeavor: the active dismantling and deorbiting of its obsolete satellites. This strategic shift marks ISRO’s transition from a pioneering launch agency to a responsible steward of the space environment, addressing the escalating crisis of orbital debris that threatens global space infrastructure.
The urgency of this mission is rooted in a simple, terrifying principle known as the Kessler Syndrome, a scenario proposed by NASA scientist Donald J. Kessler in 1978. It posits a cascading chain reaction where the density of objects in LEO becomes high enough that collisions between objects could create a cascade of further debris, each collision generating more fragments, rendering entire orbital planes unusable and potentially trapping Earth in a shell of high-velocity shrapnel. With over 8,000 satellites currently active and an estimated 36,500 pieces of debris larger than 10 cm being tracked by space surveillance networks, the threat is not science fiction; it is a clear and present danger. “Every minute piece of debris, traveling at orbital speeds of 28,000 kilometers per hour, possesses the kinetic energy of a cannonball,” explains Dr. Anil Kumar, a senior scientist at ISRO’s Space Situational Awareness (SSA) Control Centre in Bengaluru. “A collision with even a flake of paint can crack the windshield of the International Space Station. A fragment the size of a marble can catastrophically destroy a multi-million-dollar satellite. The sustainability of our operations in space is contingent on our ability to manage this man-made environment.”
ISRO’s deorbiting strategy is not a singular technology but a multi-pronged approach, meticulously planned and executed. The process begins long before a satellite’s end of life. Modern ISRO satellites, particularly those in low Earth orbit like the Indian Regional Navigation Satellite System (IRNSS) and Earth observation satellites, are now designed with what is known as ‘Design for Demise’ (DfD) principles. This means from the initial blueprint, engineers incorporate features that ensure the satellite will break up more completely and predictably upon re-entry into Earth’s atmosphere. This includes using materials with lower melting points, avoiding refractory materials like titanium in certain components, and designing structures that will disintegrate efficiently, minimizing the risk of debris surviving re-entry and reaching the Earth’s surface.
Furthermore, a critical component of end-of-life planning is the provision of adequate propellant reserves. Satellites are required to retain enough fuel to perform a final, decisive maneuver at the end of their operational lifespan. This maneuver is the deorbit burn. For satellites in very low orbits (below 600 km), natural orbital decay—caused by residual atmospheric drag—will eventually pull them down, but this process can take decades. An active deorbit burn accelerates this process dramatically, guiding the satellite towards a targeted re-entry corridor. ISRO meticulously targets a remote area of the South Pacific Ocean Uninhabited Area (SPOUA), often called the “spacecraft cemetery,” near Point Nemo, for these controlled re-entries. This is the point on Earth farthest from any landmass, making it the safest possible place for a satellite to make its final plunge.
The deorbiting process itself is a high-stakes operation. When a satellite, like the recently deorbited Megha-Tropiques-1, reaches its end-of-life, commands are sent from ISRO’s spacecraft control centre to orient it correctly. Thrusters are fired in a precise, calculated burn opposite to the direction of travel. This slows the satellite down, lowering its orbital perigee (the lowest point of its orbit) enough that it dips deep into the upper atmosphere. The immense friction generated at hypersonic speeds, combined with the intense heat, causes the satellite to break apart and vaporize. “It is a controlled sacrifice,” states Dr. Priya Sharma, an aerospace engineer at the Vikram Sarabhai Space Centre (VSSC). “We are essentially guiding a technological marvel to its fiery demise to protect the very domain it helped us explore. The calculations are incredibly precise; a slight error in the burn duration or angle could lead to an uncontrolled re-entry or fragments landing outside the designated zone.”
The case of Megha-Tropiques-1, a tropical weather monitoring satellite launched in 2011 as a joint Indo-French mission, serves as a prime example of ISRO’s proficiency and commitment. Despite having an initial mission life of three years, the satellite provided valuable data for over a decade. By 2021, its orbit had naturally decayed from 867 km to about 600 km. However, left alone, it would have remained in orbit for over a century. In a remarkable demonstration of capability, ISRO engineers performed a series of complex maneuvers in 2022, using the satellite’s last remaining propellant to lower its orbit further, ensuring its final, uncontrolled re-entry occurred within months rather than decades. This operation, conducted in collaboration with the French space agency CNES, was hailed internationally as a textbook example of responsible space behavior.
Beyond controlled re-entries, ISRO is investing heavily in pioneering technologies for future debris management. One of the most promising areas is the development of dedicated Active Debris Removal (ADR) missions. These would involve a “chaser” spacecraft designed to rendezvous with large, defunct objects—like spent rocket bodies or non-cooperative satellites that can no longer be commanded—and safely remove them from orbit. ISRO is exploring multiple capture mechanisms, including robotic arms, nets, and harpoons. Once captured, the chaser spacecraft would then act as a tugboat, deorbiting both itself and the debris. The agency has proposed missions to demonstrate this technology within the next few years, targeting some of its own derelict upper stages still circling the planet.
Another revolutionary concept being tested is the use of sails. ISRO has successfully experimented with miniaturized “deorbit sails” on its newer nanosatellites. These sails, which remain stowed during the satellite’s operational life, are deployed at end-of-mission. Even in the thin exosphere, these sails create a significant increase in atmospheric drag, acting like a brake and drastically reducing the time to natural deorbit from years to months. This low-cost, passive technology is seen as a mandatory addition for the thousands of small satellites being launched by mega-constellations like Starlink and OneWeb, and ISRO is positioning itself at the forefront of its adoption.
The scientific and engineering challenges are immense. Tracking thousands of pieces of debris requires a sophisticated SSA network. ISRO is augmenting its ground-based radar and optical telescopes and is part of international data-sharing consortia. “The physics of re-entry is brutally complex,” notes Dr. Kumar. “Modeling how a specific satellite will break up, which components might survive, and their potential trajectory requires supercomputing power and continuous validation against real-world re-entry events. Every mission provides us with more data to refine our models and increase the safety and predictability of future deorbiting operations.”
The imperative for this action is also deeply rooted in international law and diplomacy. The United Nations Committee on the Peaceful Uses of Outer Space (COPUOS) has published guidelines on the Long-term Sustainability of Outer Space Activities, which recommend that satellites in LEO be removed from orbit within 25 years of mission completion. While not legally binding, these guidelines are becoming the de facto standard for responsible spacefaring nations. By not only adhering to but exceeding these guidelines, ISRO is bolstering its reputation as a reliable and conscientious global space partner. This leadership enhances its standing in international collaborations and gives it a powerful voice in shaping the future governance of space activities. “Space is a global commons,” asserts an ISRO official involved in international relations. “No single nation can solve the debris problem alone. Our proactive efforts are a signal to the world that India is ready to lead by example and shoulder its responsibility in preserving the space domain for future generations.”
The economic rationale is equally compelling. India’s space economy is booming, with a thriving private sector and ambitious plans for its own satellite constellations. These assets, worth billions of dollars, are directly threatened by orbital debris. A single collision could wipe out critical infrastructure for communications, weather forecasting, disaster management, and national security. Investing in debris mitigation is, therefore, a direct investment in protecting India’s current and future economic and strategic assets in space. The cost of developing deorbiting technologies pales in comparison to the potential loss from a catastrophic collision.
As of late 2025, ISRO’s focus remains sharp. The organisation is systematically reviewing its orbital assets, prioritizing targets based on their collision risk and orbital lifetime. Missions are being planned not just for deorbiting, but for refueling and servicing, which could extend the lives of valuable satellites and further reduce the creation of new debris. The cultural shift within the agency is palpable; mission success is no longer measured solely by the data returned but also by the cleanliness of the departure.
ISRO’s vigorous campaign to dismantle and deorbit its obsolete satellites is a testament to its maturity and foresight. It represents a critical evolution from exploration to preservation. Through a combination of smart design, precise operations, and the development of groundbreaking removal technologies, India is not just cleaning up its own past but is helping to define a sustainable future for all spacefaring humanity. The silent, methodical work of guiding retired satellites to a watery grave in the Pacific is, in its own way, as profound as landing on the Moon or sending a probe to Mars. It is a promise to the future—a commitment that the final frontier will remain open, accessible, and safe for the explorers, scientists, and dreamers yet to come. The message from Bengaluru is clear: humanity’s journey to the stars must not be halted by the ghost of its own discarded machinery.
