GS Paper III · Science & Technology · Internal Security
🛰 Space Debris — Causes, Challenges & Removal
Definition · Scale of Problem · Causes · Kessler Syndrome · Threats · International Initiatives · India's Response · Way Forward · Updated 2024–26 Current Affairs · PYQs & MCQs
🔑
What is Space Debris? — Definition & Types
Definition First · Analogy · Classification
📖 Definition (Exam-Ready)
Space Debris (also called space junk) refers to any non-functional or discarded human-made objects in Earth's orbit that no longer serve any useful purpose. It includes:
UN COPUOS definition: "All man-made objects, including fragments and elements thereof, in Earth orbit or re-entering the atmosphere, that are non-functional."
- Defunct (dead) satellites — no longer operational
- Spent rocket stages — upper stages discarded after launch
- Fragments from collisions and explosions between space objects
- Paint flecks, nuts, bolts, and other tiny hardware released in space
- Mission-related debris — lens caps, gloves lost by astronauts, etc.
UN COPUOS definition: "All man-made objects, including fragments and elements thereof, in Earth orbit or re-entering the atmosphere, that are non-functional."
🏙 "The Orbital Garbage Problem" Analogy
Imagine a city's roads had no garbage collection for 60 years. Every abandoned car, every discarded bottle, every fallen tree would pile up — until roads become impassable. Space is facing exactly this problem, just at 28,000 km/h. The first satellite launched in 1957 started the debris problem; today, the cumulative junk of 60+ years of space activity is forming a hazardous cloud around Earth. At orbital speeds, even a 1 cm paint fleck hits with the energy of a hand grenade — the kinetic energy of space debris makes even tiny fragments lethal to satellites.
💡 Key Distinction — Debris vs Meteoroids
Space Debris = man-made objects (rockets, satellites, fragments). Created by human space activity.
Meteoroids = natural objects in space (rocks, dust from comets/asteroids).
Both are tracked by space agencies, but space debris is the growing problem because we keep adding more with every launch.
Meteoroids = natural objects in space (rocks, dust from comets/asteroids).
Both are tracked by space agencies, but space debris is the growing problem because we keep adding more with every launch.
📊
Scale of the Problem — Current Status (Updated 2025)
ESA 2025 Report · Numbers · LEO vs GEO
1.2M+
Fragments >1 cm orbiting Earth (ESA, Apr 2025)
50,000+
Pieces >10 cm — each can destroy a satellite (Apr 2025)
3,000+
New debris objects added in 2024 from fragmentation events
3×/day
Intact satellites/rocket bodies re-entering atmosphere daily (2025)
Space Debris — Size categories, count, and trackability | Data: ESA Space Environment Report 2025 | Legacy IAS
⭐ ESA Space Environment Report 2025 — Key Findings Current Affairs
- 2024 saw several major fragmentation events — adding 3,000+ new tracked objects in a single year
- In the LEO range around 550 km altitude (Starlink's primary zone), debris objects are now the same order of magnitude as active satellites — a critical density threshold
- Even without new launches, space debris would continue growing because fragmentation creates debris faster than atmospheric drag removes it
- June 2024: A defunct Russian satellite disintegrated, releasing ~100 new tracked debris pieces
- Satellites re-enter Earth's atmosphere on average more than 3 times per day in 2025
- A quarter of active constellation satellites now fly below 500 km — shorter natural deorbit times (industry response)
⚠
Causes of Space Debris — Debris Sources & Sinks
Launches · Collisions · ASAT Tests · Fragmentation
🛰 Space Debris — Sources (Launches · Operations · Deterioration · Fragmentations → Explosions · Collisions → Accidental · Deliberate) and Sinks (Orbit Decay · Deorbit · Retrieval) | Legacy IAS Information Graphic
📖 Reading the Infographic — Debris Sources vs Sinks
The infographic above shows the complete lifecycle of space debris. Sources (top) are inputs that ADD debris to the orbital population. Sinks (bottom) are mechanisms that REMOVE debris. The problem: sources are outpacing sinks.
4 Sources: Launches (spent rocket stages) · Operations (decommissioned satellites, lost hardware) · Deterioration (degradation of surfaces, paint) · Fragmentations (explosions or collisions creating clouds of smaller debris)
3 Sinks: Orbit Decay (atmospheric drag gradually pulls LEO debris down — faster at lower altitudes) · Deorbit (deliberate powered re-entry — controlled) · Retrieval (future active removal technology)
4 Sources: Launches (spent rocket stages) · Operations (decommissioned satellites, lost hardware) · Deterioration (degradation of surfaces, paint) · Fragmentations (explosions or collisions creating clouds of smaller debris)
3 Sinks: Orbit Decay (atmospheric drag gradually pulls LEO debris down — faster at lower altitudes) · Deorbit (deliberate powered re-entry — controlled) · Retrieval (future active removal technology)
🚀
1. Satellite Launches
Every launch leaves rocket stages in orbit. SpaceX's Starlink alone = half of all active satellites. ~12,000 planned (possible extension to 42,000). Amazon Kuiper, OneWeb, and China's Guowang mega-constellations adding thousands more. Each satellite = potential future debris.
💀
2. Defunct Satellites
~3,000 decommissioned satellites in orbit (Natural History Museum data). Once a satellite runs out of fuel or malfunctions, it cannot manoeuvre and remains as debris. GEO debris can remain for centuries — atmospheric drag is negligible at 36,000 km.
💥
3. Anti-Satellite (ASAT) Tests
China (2007): FengYun-1C ASAT test increased trackable space objects by 25% in one event — single largest debris-generating event. India (2019): Mission Shakti at ~283 km (low altitude, chose deliberately for faster decay). Russia (2021): Nudol ASAT test created 1,500+ trackable fragments, endangered ISS crew.
🔄
4. Fragmentation (Explosions & Collisions)
Accidental collisions: 2009 — Iridium 33 vs Kosmos-2251 (first accidental satellite collision in history, created 2,000+ fragments). Explosions: Residual propellant or pressurised batteries can explode years after a mission ends. One explosion = thousands of new fragments.
🔩
5. Operational Debris
Lost hardware during space missions — gloves, cameras, tool bags (a US astronaut lost a tool bag in 2023, tracked for months). Lens caps, separation bolts, fairings. All too small to retrieve but large enough to damage spacecraft on impact.
🎨
6. Surface Deterioration
Spacecraft surfaces degrade in space — UV radiation, atomic oxygen, and thermal cycling cause paint, insulation, and surface materials to flake off, creating millions of sub-millimetre particles too small to track but capable of sandblasting solar panels and optics.
💥
Kessler Syndrome — The Doomsday Scenario
Chain Reaction · Donald Kessler 1978 · Orbital Unusability
📖 Kessler Syndrome — Definition
Kessler Syndrome (proposed by NASA scientist Donald J. Kessler in 1978) = a scenario where the density of space debris in LEO becomes so high that collisions between objects generate more debris, which causes more collisions, creating a self-sustaining cascade of destruction — ultimately rendering certain orbital shells permanently unusable for satellites or spacecraft.
The cascade: Debris hits satellite → satellite breaks into 1,000 fragments → each fragment hits another object → each creates 1,000 more fragments → exponential growth → orbit becomes unusable.
The cascade: Debris hits satellite → satellite breaks into 1,000 fragments → each fragment hits another object → each creates 1,000 more fragments → exponential growth → orbit becomes unusable.
Kessler Syndrome Cascade — The Domino Effect in Orbit | Legacy IAS Original (CC0)
🎳 "Bowling Ball in a Glass Shop" Analogy
Imagine a bowling ball thrown through a glass shop. The ball shatters the first shelf — the glass fragments fly out and shatter more shelves — those fragments hit even more — until the entire shop is destroyed by fragments from fragments. Now imagine this happening in LEO at 28,000 km/h. The first collision creates fragments that cause the next collision, which creates more fragments — each collision amplifies the next. Unlike on Earth, there's no gravity to pull the fragments down quickly — they remain in orbit for years, decades, or centuries (depending on altitude).
📍
Where is Kessler Syndrome Risk Highest?
LEO (300–2,000 km): Most debris, most satellites, highest collision probability. Especially dangerous at 550 km (Starlink) and 800–1,000 km (where debris lingers for decades).
GEO (35,786 km): Debris lingers for centuries to millennia — no atmospheric drag. But fewer objects, so risk lower today.
ESA 2025: At 550 km altitude, debris density = same order of magnitude as active satellites — approaching the cascade threshold.
GEO (35,786 km): Debris lingers for centuries to millennia — no atmospheric drag. But fewer objects, so risk lower today.
ESA 2025: At 550 km altitude, debris density = same order of magnitude as active satellites — approaching the cascade threshold.
📡
What Would Kessler Syndrome Mean for India?
Communication failure: GSAT, CMS satellites disrupted
Navigation loss: NaVIC and GPS disrupted — affects fishermen, military, logistics
Weather forecasting: INSAT weather data lost — cyclone warnings impossible
Military: EMISAT, RISAT surveillance satellites lost
Agriculture: Crop monitoring satellites gone
Gaganyaan: Human spaceflight becomes impossibly dangerous
Estimated economic cost to India: Hundreds of thousands of crores.
Navigation loss: NaVIC and GPS disrupted — affects fishermen, military, logistics
Weather forecasting: INSAT weather data lost — cyclone warnings impossible
Military: EMISAT, RISAT surveillance satellites lost
Agriculture: Crop monitoring satellites gone
Gaganyaan: Human spaceflight becomes impossibly dangerous
Estimated economic cost to India: Hundreds of thousands of crores.
🚨
Threats & Challenges Posed by Space Debris
Satellites · ISS · Future Missions · Geopolitics
🛰
Satellite Damage & Destruction
Debris collisions destroy operational satellites — severe economic and strategic loss. 1981: Cosmos-1275 (first debris-damaged satellite). 2009: Iridium 33 vs Kosmos-2251 — first accidental collision. At orbital speeds, 1 cm debris = equivalent to a hand grenade impact.
🏠
Space Station Vulnerability
ISS has corrected orbit 32 times since 1999 to avoid debris (NASA). Russia's 2021 ASAT test caused ISS crew to shelter in docked spacecraft. Future Gaganyaan and Bharatiya Antariksh Station (BAS) face same threat — making debris a national security concern.
🔒
Orbital Slot Scarcity
Most desirable orbital altitudes are finite resource. Debris occupies prime LEO and GEO "real estate." Growing debris clouds make certain altitude bands increasingly hazardous — reducing available slots for new satellite launches. Developing countries hardest hit — they launch last, when orbits are already crowded.
🌍
Re-entry Risk to Earth
Kenya, Jan 2024: A 500 kg metal object (rocket debris) crashed in Kenya — sparking global accountability concerns. Most debris burns up in re-entry, but large metal components (rocket stages, fuel tanks) can survive. No international compensation framework effectively enforced.
⚡
Radio Frequency Disruption
Large satellite constellations (especially Starlink) and debris interfere with radio frequency bands used for communication, weather forecasting, and disaster management. Astronomers report satellite streaks ruining telescope observations — the "light pollution" of space.
🌐
Geopolitical Tensions
USA accused Russia of endangering ISS after 2021 ASAT test. China's 2007 test created debris threatening all countries' satellites. Disputes over who pays compensation when space objects collide. No binding enforcement under Outer Space Treaty (1967) or Liability Convention (1972).
🌐
International Initiatives & Legal Framework
Treaties · IADC · COPUOS · ClearSpace · Zero Debris Charter
| Initiative / Treaty | Year | Key Provisions | Limitations | India's Status |
|---|---|---|---|---|
| Outer Space Treaty | 1967 | Article VI: States responsible for all national space activities (including private). Article VII: Launching state liable for damage caused by space objects. Prohibits WMDs in space. | No enforcement mechanism. No binding debris mitigation provisions. Lacks clarity on "damage" in orbit. | ✅ India is signatory |
| Liability Convention | 1972 | Launching state absolutely liable to pay compensation for damage on Earth's surface or aircraft. Fault-based liability for space-to-space damage. Only one successful claim: Canada claimed $3M from USSR for Cosmos-954 satellite crash (1978). | Enforcement weak. Never settled major space-to-space collision claim. Private sector accountability unclear. | ✅ India is signatory |
| IADC Inter-Agency Space Debris Coordination Committee |
1993 | First international forum for space debris coordination. Formulated IADC Space Debris Mitigation Guidelines (2002): 25-year deorbit rule, passivation of spacecraft, protect LEO and GEO regions. | Guidelines are voluntary — ~30% compliance rate globally. | ✅ ISRO is a member |
| COPUOS UN Committee on Peaceful Uses of Outer Space |
1958 | 18 founding members (India is founding member). Governs space exploration for all humanity. Adopted 21 Voluntary Guidelines for Long-Term Sustainability of Outer Space (2019). | Voluntary guidelines. Conflicting national/commercial priorities. No binding enforcement. | ✅ India = founding member |
| Zero Debris Charter (ESA-led) | 2023 | Global initiative to eliminate space debris by 2030. 12 countries signed initially. Aims: no new debris creation, sustainable deorbit plans, best practice sharing. SpaceX under pressure to join. | Major commercial players (SpaceX) not yet signatories. Targets are aspirational. | ⚠ India committed to "Debris Free Space Missions by 2030" (ISRO, April 2024) — aligned but formal charter status unclear |
| ClearSpace-1 (ESA) | Planned 2028 | First mission to actively remove a piece of space debris from orbit. Target: VESPA (Vega Secondary Payload Adapter) rocket body at ~800 km. Uses robotic arms for capture, then controlled re-entry. | One piece removed. 50,000+ >10 cm pieces need removal. Extremely expensive (~€86M for one piece). | India watching. ISRO has no equivalent Active Debris Removal (ADR) mission announced yet. |
| ESA Clean Space Initiative | 2012 | ESA programme to ensure space environment sustainability. Designing for demise (satellites that fully burn up on re-entry). Remove DEBRIS mission demonstrated harpoon, net, and drag sail technologies. | Technology demonstrations completed, scaling remains expensive. | India follows but has no equivalent formal programme. |
🇮🇳
India's Response to Space Debris
IS4OM · NETRA · SSA · Megha-Tropiques · ISRO's 2030 Pledge
⭐ ISRO's Pledge — "Debris Free Space Missions by 2030" April 2024
In April 2024, ISRO formally pledged to pursue "Debris Free Space Missions" by 2030 — committing to design all future Indian satellites and rockets with end-of-life disposal plans, controlled deorbit capability, and passivation systems (draining residual fuel/energy to prevent explosion). This aligns India with international best practices and ESA's Zero Debris Charter goals.
🔭
IS4OM — ISRO System for Safe & Sustainable Operations Management (2022)
ISRO's holistic approach to space safety. Functions:
✅ Continuously monitors objects posing collision threats to Indian satellites
✅ Predicts evolution of space debris environment
✅ Coordinates collision avoidance manoeuvres
✅ Analyses re-entry predictions
2022: Performed 21 Collision Avoidance Manoeuvres (CAM) for Indian operational satellites. (2021: 19 CAMs)
✅ Continuously monitors objects posing collision threats to Indian satellites
✅ Predicts evolution of space debris environment
✅ Coordinates collision avoidance manoeuvres
✅ Analyses re-entry predictions
2022: Performed 21 Collision Avoidance Manoeuvres (CAM) for Indian operational satellites. (2021: 19 CAMs)
📡
Project NETRA — Network for Space Object Tracking & Analysis
India's own Space Situational Awareness (SSA) system. Capabilities:
✅ Spots, tracks, and catalogues objects as small as 10 cm
✅ Range: up to 3,400 km
✅ Early warning for debris approaching Indian satellites
Infrastructure: Space debris tracking radar (1,500 km range) + optical telescope. Coordinated by ISRO's SSA Control Centre, Bengaluru (est. 2020). India-USA 2022 agreement for space object monitoring data sharing.
✅ Spots, tracks, and catalogues objects as small as 10 cm
✅ Range: up to 3,400 km
✅ Early warning for debris approaching Indian satellites
Infrastructure: Space debris tracking radar (1,500 km range) + optical telescope. Coordinated by ISRO's SSA Control Centre, Bengaluru (est. 2020). India-USA 2022 agreement for space object monitoring data sharing.
🛸
Megha-Tropiques-1 — India's First Controlled Deorbit (April 2023)
Historic first: In April 2023, ISRO performed India's first controlled deorbit of a satellite — Megha-Tropiques-1 (launched 2011, India-France joint Earth observation satellite). After its useful life ended, ISRO used the remaining propellant to perform eight deorbit burns over several months, bringing it from ~867 km to a precise controlled re-entry over the Pacific Ocean. This demonstrated ISRO's commitment to responsible debris management.
🏛
ISRO SSA Control Centre + Centre for Space Debris Research
SSA Control Centre (2020): Hub for all Space Situational Awareness activities — tracking near-Earth objects, debris, and potential threats to Indian assets. Managed by Directorate of Space Situational Awareness and Management at ISRO HQ.
Centre for Space Debris Research: Monitors and studies debris evolution. Provides data for ISRO mission planning and end-of-life disposal strategies.
Centre for Space Debris Research: Monitors and studies debris evolution. Provides data for ISRO mission planning and end-of-life disposal strategies.
💡 India's Debris Numbers (Government Announcement)
The Government of India officially announced that 111 payloads (functional and non-functional Indian satellites) and 105 space debris objects have been identified as Indian objects currently orbiting Earth. This transparency is part of India's commitment to responsible space governance.
🤖
Space Debris Removal Technologies & Way Forward
Active Removal · Passive Methods · Prevention · Future Tech
Active Debris Removal (ADR) Technologies
🎣
Harpoon & Net Systems
Fire a harpoon to puncture and anchor to debris, or deploy a net to capture tumbling objects. RemoveDEBRIS mission (ESA, 2018) successfully demonstrated net capture in orbit. Challenge: debris tumbles at high speed — capturing without creating more fragments is complex.
🦾
Robotic Arms (ClearSpace-1)
ESA's ClearSpace-1 (planned 2028) uses four robotic arms to grapple the VESPA rocket body. After capture, controlled re-entry burns the debris in atmosphere. Most precise method — but one piece removed per mission. Cost: ~€86 million per debris piece.
🧲
Magnetic Capture (Astroscale ELSA)
Astroscale (Japan) ELSA-d mission: Uses magnetic docking plate pre-installed on satellites during manufacture. Removal spacecraft attaches magnetically and deorbits. Only works if debris has magnetic docking plate — requires forward planning. Elegant solution for new satellites.
⚡
Laser Broom
Ground-based or space-based laser ablates (vaporises) surface of debris — creating tiny thrust to alter orbit. Can nudge small debris into lower orbits where atmospheric drag causes re-entry. No physical contact needed. Effective for small debris (<10 cm) that's too small to capture physically.
🪂
Drag Sails & Deorbit Kits
Large membrane (sail) deployed from satellite at end-of-life — increases atmospheric drag, causing faster orbital decay. Passive, cheap, reliable. Can reduce deorbit time from decades to years. RemoveDEBRIS tested successfully. India's future satellites can incorporate this technology.
🔋
Ion Beam Shepherd
A spacecraft positions itself near debris and fires ion thrusters at it — the ion beam gradually pushes the debris into a lower orbit without physical contact. Contactless method — avoids risk of creating more fragments. Still experimental. Could handle large, tumbling debris safely.
Prevention — Better Than Cure
🔄
Reusable Launch Vehicles (RLVs)
SpaceX Falcon 9 recovers first stages — no rocket bodies left in orbit. ISRO's RLV programme (LEX-02, LEX-03 tests in 2024) aims to develop similar capability. Reusable rockets = no spent stages = less debris created per launch. Critical for India's growing launch frequency.
📋
Design for Demise (D4D)
Build satellites using materials that fully burn up during re-entry — titanium replaced with aluminium alloys that vaporise completely. Passivation: drain all residual fuel, batteries, pressurised fluids at end-of-life to prevent explosion. New ISRO satellites incorporating these standards.
🛰
25-Year Deorbit Rule (IADC) & FCC's 5-Year Rule
IADC guideline: LEO satellites must deorbit within 25 years of end-of-mission. Global compliance: only ~30%. FCC (USA, 2022): Tightened to 5-year deorbit rule for US-licensed satellites — major policy tightening. India follows 25-year rule and is moving toward faster deorbit timelines.
📡
Space Traffic Management (STM)
Treating space orbits like air traffic — defined "lanes," right-of-way rules, coordination centres. Currently voluntary and fragmented. Calls for UN-led binding STM framework growing. India participates in COPUOS discussions. Automation and AI for real-time collision avoidance being explored.
📜
UPSC PYQs — Space Debris
Actual Questions · Verified Answers
⭐ UPSC Prelims 2016 — Space Debris / BHUVAN PatternActual PYQ
With reference to "Kessler Syndrome" sometimes seen in news, which of the following statements is/are correct?
1. Kessler Syndrome refers to a scenario where the density of objects in LEO due to space pollution is high enough that collisions between objects could cause a cascade, making space activities and the use of satellites in certain orbital ranges difficult for many generations.
2. It was first proposed by NASA scientist Donald Kessler.
3. Currently, Earth's orbital environment has already reached Kessler Syndrome status.
1. Kessler Syndrome refers to a scenario where the density of objects in LEO due to space pollution is high enough that collisions between objects could cause a cascade, making space activities and the use of satellites in certain orbital ranges difficult for many generations.
2. It was first proposed by NASA scientist Donald Kessler.
3. Currently, Earth's orbital environment has already reached Kessler Syndrome status.
- (a) 1 and 2 only ✅
- (b) 1 and 3 only
- (c) 2 and 3 only
- (d) 1, 2 and 3
Statement 1 ✅ Correct: Accurate definition — Kessler Syndrome is the cascade scenario where debris density becomes self-sustaining, making certain orbital zones unusable for generations.
Statement 2 ✅ Correct: Proposed by Donald J. Kessler (NASA scientist) in 1978 in a paper co-authored with Burton Cour-Palais.
Statement 3 ✗ WRONG: We have NOT yet reached Kessler Syndrome — it remains a risk scenario/theoretical framework, not a current reality. However, ESA (2025) warns we are approaching critical density thresholds in certain altitude bands (especially 550 km where Starlink operates). The concern is that without Active Debris Removal, the cascade could begin in coming decades.
Statement 2 ✅ Correct: Proposed by Donald J. Kessler (NASA scientist) in 1978 in a paper co-authored with Burton Cour-Palais.
Statement 3 ✗ WRONG: We have NOT yet reached Kessler Syndrome — it remains a risk scenario/theoretical framework, not a current reality. However, ESA (2025) warns we are approaching critical density thresholds in certain altitude bands (especially 550 km where Starlink operates). The concern is that without Active Debris Removal, the cascade could begin in coming decades.
⭐ UPSC Mains 2014 — International Airspace/Space LawMains 2014
"International civil aviation laws provide all countries complete and exclusive sovereignty over the airspace above their territory. What do you understand by 'airspace'? What are the implications of these laws on the space above this airspace? Discuss the challenges which this poses and suggest ways to contain the threat." (UPSC Mains 2014)
Model Answer Key Points:
Airspace definition: Sovereign airspace extends from a nation's territory upward but there is no universally agreed boundary with "outer space." Kármán line (100 km) = informal/conventional boundary. Below = airspace (Chicago Convention 1944). Above = outer space (Outer Space Treaty 1967 = "province of all mankind").
Implications: No nation can claim sovereignty over outer space — all orbits are international commons. Satellites can fly over any country without permission. But debris generated in "international" orbit by one nation harms all. Liability Convention (1972) partially addresses this.
Challenges: Who owns orbital slots? (ITU allocates GEO slots — scarce resource). Who is responsible for debris? (Launching state — but enforcement weak). Chain reaction risk (Kessler Syndrome). ASAT tests polluting international commons. Private company accountability (SpaceX Starlink).
Way forward: Binding Space Traffic Management (STM) framework under UN. Mandatory deorbit plans. IADC guidelines made binding through COPUOS. Universal liability for debris damage. Carbon/debris taxation on launches. Orbital reservations for developing countries (like spectrum reservations).
Implications: No nation can claim sovereignty over outer space — all orbits are international commons. Satellites can fly over any country without permission. But debris generated in "international" orbit by one nation harms all. Liability Convention (1972) partially addresses this.
Challenges: Who owns orbital slots? (ITU allocates GEO slots — scarce resource). Who is responsible for debris? (Launching state — but enforcement weak). Chain reaction risk (Kessler Syndrome). ASAT tests polluting international commons. Private company accountability (SpaceX Starlink).
Way forward: Binding Space Traffic Management (STM) framework under UN. Mandatory deorbit plans. IADC guidelines made binding through COPUOS. Universal liability for debris damage. Carbon/debris taxation on launches. Orbital reservations for developing countries (like spectrum reservations).
⭐ Expected Mains 2026 — Space Debris & India250 Words | 15 Marks
"Space debris is no longer a distant threat but an immediate challenge to India's space ambitions. Analyse the causes, consequences, and India's response to the growing menace of space junk."
Causes: Mega-constellations (Starlink = half of active sats; 42,000 planned). Dead satellites (~3,000). ASAT tests — China 2007 (25% spike), India Mission Shakti 2019, Russia 2021 (endangered ISS). Explosions + collisions (Iridium-Kosmos 2009). Surface deterioration + operational debris.
Scale: 1.2M+ fragments >1cm (ESA 2025). 50,000+ trackable >10cm. 3,000+ added in 2024. India: 111 payloads + 105 debris objects identified.
Consequences for India: ISS corrections 32 times. Gaganyaan/BAS threatened. NaVIC, GSAT, INSAT, RISAT, EMISAT all vulnerable. Kessler Syndrome risk at 550 km altitude band. Kenya rocket debris crash (2024) = liability precedent.
India's Response: IS4OM (2022) — monitoring & 21 CAMs. Project NETRA — tracks to 10cm, 3,400 km range. SSA Control Centre (2020, Bengaluru). Megha-Tropiques-1 controlled deorbit (April 2023 — India's first). ISRO "Debris Free Space Missions by 2030" pledge (April 2024). Member of IADC. Founding member COPUOS. India-USA SSA data sharing (2022). RLV programme (reusable rockets reduce debris).
Way Forward: Enact Space Activities Act with mandatory end-of-life disposal. Scale Project NETRA. Develop Active Debris Removal mission. Sign Zero Debris Charter. Push for binding COPUOS framework. Design for demise in future satellites. Space Traffic Management system.
Scale: 1.2M+ fragments >1cm (ESA 2025). 50,000+ trackable >10cm. 3,000+ added in 2024. India: 111 payloads + 105 debris objects identified.
Consequences for India: ISS corrections 32 times. Gaganyaan/BAS threatened. NaVIC, GSAT, INSAT, RISAT, EMISAT all vulnerable. Kessler Syndrome risk at 550 km altitude band. Kenya rocket debris crash (2024) = liability precedent.
India's Response: IS4OM (2022) — monitoring & 21 CAMs. Project NETRA — tracks to 10cm, 3,400 km range. SSA Control Centre (2020, Bengaluru). Megha-Tropiques-1 controlled deorbit (April 2023 — India's first). ISRO "Debris Free Space Missions by 2030" pledge (April 2024). Member of IADC. Founding member COPUOS. India-USA SSA data sharing (2022). RLV programme (reusable rockets reduce debris).
Way Forward: Enact Space Activities Act with mandatory end-of-life disposal. Scale Project NETRA. Develop Active Debris Removal mission. Sign Zero Debris Charter. Push for binding COPUOS framework. Design for demise in future satellites. Space Traffic Management system.
🧪
Practice MCQs — Space Debris
10 Questions · Click to Attempt
📝 10 MCQs — All Key Concepts + Current Affairs 2024–26 · Click option to attempt
Q1. China's 2007 FengYun-1C anti-satellite test was particularly significant from a space debris perspective because:
- (a) It was the first-ever anti-satellite test conducted by any country
- (b) The debris it created immediately triggered Kessler Syndrome in LEO
- (c) It increased the total population of trackable space objects by approximately 25% in a single event — the single largest debris-generating event in history ✅
- (d) China used it to demonstrate that GEO debris is more dangerous than LEO debris
✅ (c). China's FengYun-1C ASAT test (January 11, 2007) destroyed China's own weather satellite at ~865 km altitude — creating approximately 3,000 trackable debris fragments and over 35,000 pieces larger than 1 cm. This increased the global trackable debris population by about 25% in a single event — the most debris ever generated by a single event until Russia's 2021 ASAT test. The debris is at high altitude (800–900 km) where atmospheric drag is minimal — many fragments will remain in orbit for centuries. India's Mission Shakti ASAT test (2019) deliberately chose a much lower altitude (~283 km) so debris would decay faster.
Q2. Project NETRA (Network for Space Object Tracking and Analysis) by ISRO is primarily designed to:
- (a) Track Indian astronauts during the Gaganyaan mission and monitor their health
- (b) Provide India with indigenous Space Situational Awareness capability — detecting, tracking, and cataloguing space debris and other objects that pose collision threats to Indian satellites ✅
- (c) Monitor China's and Pakistan's military satellite movements for defence intelligence
- (d) Track meteoroids and asteroids approaching Earth for planetary defence
✅ (b). Project NETRA = India's early warning system for Space Situational Awareness (SSA). Capabilities: tracks objects as small as 10 cm within a range of 3,400 km. Components: space debris tracking radar (1,500 km range) + optical telescope. Coordinated from ISRO's SSA Control Centre in Bengaluru (established 2020). In 2022, ISRO performed 21 Collision Avoidance Manoeuvres (CAMs) based on debris tracking data — up from 19 in 2021. India also signed a data-sharing agreement with USA (2022) for space object monitoring to supplement NETRA's capabilities. IS4OM (launched 2022) is the broader institutional framework within which NETRA operates.
Q3. Which of the following statements about the Liability Convention of 1972 is INCORRECT?
- (a) A launching state is absolutely liable for damage caused by its space objects on Earth's surface
- (b) The only successful claim under this convention was Canada's $3 million claim against the USSR for the Cosmos-954 nuclear satellite crash in Canada (1978)
- (c) For damage caused in space (space-to-space), the convention requires proof of fault — not absolute liability
- (d) The Convention provides a clear and enforceable mechanism for compensation when satellites from different countries collide in orbit ✅
✅ (d) is INCORRECT. The Liability Convention lacks a clear, enforceable mechanism for space-to-space collisions. Key facts: Absolute liability applies to damage on Earth's surface (no need to prove fault). Fault-based liability applies for space-to-space damage. The only successful invocation: Canada claimed compensation from USSR for Cosmos-954 nuclear satellite that crashed in Canada (1978) — settled for $3 million. Major weakness: no independent adjudication body, no enforcement mechanism. If Iridium 33 vs Kosmos-2251 (2009) — first accidental collision — had been pursued, the Convention's weakness would have been exposed. In practice, space-to-space collision damage has never been compensated under this Convention. The 2024 Kenya rocket debris crash re-ignited calls for stronger liability mechanisms.
Q4. India performed its first controlled deorbit of a satellite in April 2023. Which satellite was deorbited, and why is this historically significant?
- (a) Megha-Tropiques-1 (India-France joint Earth observation satellite, launched 2011) — using its remaining propellant for controlled re-entry over the Pacific Ocean, demonstrating India's commitment to responsible space debris management ✅
- (b) RISAT-2 (radar imaging satellite) — India's first military satellite deorbited under international pressure from China
- (c) Chandrayaan-2 orbiter — deliberately crashed into the Moon's surface to end its mission
- (d) AstroSat — India's first space observatory deorbited after completion of 5-year mission in 2023
✅ (a). Megha-Tropiques-1 (MT-1): India-France joint satellite for tropical weather and climate research. Launched October 2011. Originally designed for 3-year life but operated for 11+ years. In April 2023, ISRO used remaining propellant to perform 8 controlled deorbit burns over several months, lowering the orbit from ~867 km until atmospheric re-entry burned up most of the satellite over the Pacific Ocean. This was India's first controlled deorbit — demonstrating ISRO's ability to responsibly end satellite missions without leaving long-lasting debris. Significant because at 867 km altitude, uncontrolled decay would have taken ~100 years. Controlled deorbit = immediate debris prevention. This practice aligns with ISRO's "Debris Free Space Missions by 2030" commitment announced in April 2024.
Q5. ESA's ClearSpace-1 mission is described as a landmark in space debris management. What makes it historically unique?
- (a) It is the first satellite specifically designed to survive Kessler Syndrome conditions and operate in debris-dense orbits
- (b) It will be the first mission to physically capture and remove an existing piece of space debris from orbit — using robotic arms to grapple a rocket body and guide it to controlled re-entry ✅
- (c) ClearSpace-1 is the first international space mission jointly operated by all five permanent UN Security Council members
- (d) It uses nuclear propulsion to generate enough thrust to move large debris pieces from LEO to GEO graveyard orbit
✅ (b). ClearSpace-1 (ESA): planned 2028 launch (delayed from earlier planned 2025/2026 dates). Target: VESPA (Vega Secondary Payload Adapter) — a 112 kg ESA rocket body at ~800 km altitude, in orbit since 2013. Method: 4 robotic arms grapple the target, then controlled re-entry burns the debris in atmosphere. Cost: ~€86 million. World's first Active Debris Removal (ADR) mission that physically captures an existing piece of debris (not newly released test hardware). Earlier missions like RemoveDEBRIS (2018) demonstrated technologies (harpoon, net, drag sail) but used freshly deployed test targets, not existing orbital debris. Critical limitation: one piece per mission at enormous cost — 50,000+ pieces >10 cm need removal.
Q6. IADC Space Debris Mitigation Guidelines (2002) recommend that LEO satellites should deorbit within 25 years of end-of-mission. What is the global compliance rate with this guideline, and what has the USA's FCC recently done?
- (a) ~80% compliance globally; FCC extended the rule to 50 years for commercial satellites in 2023
- (b) ~60% compliance; FCC adopted the same 25-year rule as mandatory for US satellites in 2022
- (c) Only ~30% compliance globally; the US FCC in 2022 tightened this to a 5-year deorbit rule for US-licensed LEO satellites — a major policy shift ✅
- (d) ~95% compliance; the issue is with non-member states of IADC outside the framework
✅ (c). Global compliance with the IADC 25-year deorbit guideline = approximately 30% — meaning 70% of satellites are NOT being deorbited within 25 years as recommended. This is a major systemic failure. USA's FCC response (2022): Changed the US rule from 25-year to 5-year post-mission disposal for US-licensed LEO satellites — a dramatic tightening. Rationale: 25 years is too long given the rapid growth of satellite constellations; more debris accumulates during 25-year waits. SpaceX (Starlink) already follows this for most of its satellites. India follows the IADC 25-year guideline and has committed to moving toward faster deorbit timelines under its 2030 Debris Free pledge. ESA's Zero Debris Charter (2023) also pushed for faster deorbit standards.
Q7. The 2009 collision between Iridium 33 and Kosmos-2251 was significant because it was:
- (a) The first debris re-entry that caused casualties on Earth's surface
- (b) The first collision between a defunct satellite and an asteroid fragment
- (c) The first intentional collision test conducted by the USA to study debris creation patterns
- (d) The first accidental collision between two intact satellites in orbit — creating approximately 2,000 new trackable fragments ✅
✅ (d). February 10, 2009: Iridium 33 (active US commercial communication satellite) collided with Kosmos-2251 (defunct Russian military satellite) at ~789 km altitude over Siberia. Speed of collision: ~11.7 km/s. This was the first-ever collision between two intact spacecraft — creating approximately 2,000 trackable debris fragments (plus tens of thousands of smaller pieces). Neither satellite could manoeuvre — the Kosmos was defunct (no propulsion) and the Iridium wasn't given timely warning (failure of space traffic coordination). This collision demonstrated the need for international Space Traffic Management (STM), improved debris tracking, and mandatory collision avoidance planning. The debris field from this collision continues to endanger other satellites to this day.
Q8. ISRO's IS4OM (ISRO System for Safe and Sustainable Operations Management) was launched in 2022. Which of the following correctly describes its functions?
- (a) It monitors objects posing collision threats to Indian satellites, predicts debris evolution, coordinates collision avoidance manoeuvres, and provides a holistic framework for safe Indian space operations ✅
- (b) It is a rocket recovery system for recovering ISRO's spent rocket stages from the ocean for reuse
- (c) IS4OM is India's active debris removal spacecraft — launched to capture and deorbit defunct Indian satellites
- (d) It is an orbital refuelling station concept to extend Indian satellite operational lifespans
✅ (a). IS4OM (launched 2022) = ISRO's holistic space operations safety management framework. Key functions: (1) Continuously monitor all objects posing collision risks to Indian satellites using radar and optical data. (2) Predict evolution of space debris environment — forecast density increase. (3) Plan and execute Collision Avoidance Manoeuvres (CAMs) — 21 CAMs performed in 2022, up from 19 in 2021. (4) Analyse re-entry predictions for debris heading toward Earth. (5) Coordinate with global Space Situational Awareness (SSA) networks. IS4OM interfaces with Project NETRA (tracking) and the ISRO SSA Control Centre in Bengaluru (operations hub). It is NOT a physical removal mission (option c) — that remains a future aspiration for India. It is the institutional framework for protecting existing Indian assets.
Q9. India's Committee on Peaceful Uses of Outer Space (COPUOS) membership is particularly notable because:
- (a) India recently joined COPUOS in 2019 following Mission Shakti's ASAT test success
- (b) India was a founding member of COPUOS (established 1958) with 18 original members — giving India significant moral authority and diplomatic weight in all outer space governance discussions ✅
- (c) India leads COPUOS as its permanent chairperson, giving it veto power over outer space resolutions
- (d) COPUOS was established in 1993 alongside the IADC after the Cold War's space debris legacy became apparent
✅ (b). COPUOS (Committee on the Peaceful Uses of Outer Space) was established by the UN General Assembly in 1958 — the year Sputnik was launched (1957) made the world realise space governance was needed. It had 18 founding members, including India. Today COPUOS has 102 members (as of 2024). COPUOS governs exploration and use of outer space for benefit of all humanity. Key achievements: Outer Space Treaty (1967), Rescue Agreement (1968), Liability Convention (1972), Registration Convention (1976), Moon Agreement (1979), 21 Voluntary Guidelines for Long-Term Sustainability of Outer Space Activities (2019). India's founding membership gives it standing, credibility, and influence in all outer space governance negotiations — including space debris, satellite frequency allocation, and commercial space regulation. IADC was established in 1993 (not COPUOS — option d is wrong).
Q10. As per ESA's Space Environment Report 2025, which of the following statements about the current space debris situation is CORRECT?
- (a) The total number of tracked debris objects decreased in 2024 due to improved deorbit compliance
- (b) Kessler Syndrome has already been triggered in the altitude band of 550 km and is now irreversible
- (c) All space debris pieces larger than 1 cm are now tracked by global radar networks
- (d) In 2024, several major fragmentation events added 3,000+ new tracked objects in a single year; debris density at 550 km altitude is now the same order of magnitude as active satellites ✅
✅ (d). ESA Space Environment Report 2025 (covering data through end of 2024): Multiple major fragmentation events + several smaller ones added at least 3,000+ new tracked debris objects in 2024 alone. At 550 km altitude (Starlink's primary operational zone), the density of debris objects is now the same order of magnitude as active satellites — a critical threshold warning that we are approaching a tipping point. Option (a) WRONG: Debris population grew, not decreased. Option (b) WRONG: Kessler Syndrome has NOT been triggered — still a risk scenario, not a current reality. Option (c) WRONG: Only objects larger than ~10 cm in LEO are trackable by current radar — ~1.2 million fragments larger than 1 cm exist but most cannot be tracked. This tracking gap is why collision avoidance is so challenging.
⚡ Quick Revision — Space Debris Complete Summary
| Topic | Exam-Ready Facts |
|---|---|
| Definition | Non-functional human-made objects in Earth's orbit. Includes defunct satellites, spent rocket stages, collision fragments, paint flecks. "Space junk." |
| Current Scale (2025) | 1.2M+ fragments >1 cm · 50,000+ trackable >10 cm · 3,000+ new added in 2024 · 550 km band: debris = active satellite density. India: 111 payloads + 105 debris objects. |
| Key Events | China FengYun-1C ASAT 2007 = +25% trackable debris. Iridium 33 + Kosmos-2251 collision 2009 = first accidental collision. India Mission Shakti ASAT 2019 (low altitude = faster decay). Russia ASAT 2021 = endangered ISS. Kenya rocket debris crash 2024. |
| Kessler Syndrome | Proposed by Donald Kessler, NASA, 1978. Cascade: debris hits satellite → fragments hit more satellites → exponential growth → orbit unusable. NOT yet triggered but risk growing at 550 km band. |
| India's Initiatives | IS4OM (2022) — monitoring + 21 CAMs. Project NETRA — tracks 10cm objects, 3,400 km range. SSA Control Centre (2020) — Bengaluru. Megha-Tropiques-1 controlled deorbit (April 2023) — India's first. Debris Free Space Missions by 2030 (April 2024) — ISRO pledge. |
| International Frameworks | Outer Space Treaty 1967. Liability Convention 1972. IADC 1993 (25-year deorbit rule, ~30% compliance). COPUOS 1958 (India founding member). Zero Debris Charter 2023. ClearSpace-1 (ESA, 2028 — first ADR mission). FCC 5-year rule (USA, 2022). |
| Removal Technologies | Harpoon + net · Robotic arms (ClearSpace-1) · Magnetic capture (Astroscale ELSA) · Laser broom · Drag sails · Ion beam shepherd |
| Prevention | Reusable rockets (less debris per launch). Design for demise. 25/5-year deorbit rule. Passivation. Space Traffic Management (STM). No deliberate ASAT tests. |
🚨 5 UPSC Traps — Space Debris:
Trap 1 — "Kessler Syndrome has already occurred" → WRONG! Kessler Syndrome remains a theoretical risk scenario — NOT yet triggered. However, ESA 2025 warns we are approaching critical thresholds at 550 km altitude. We are at risk, not at syndrome.
Trap 2 — "India's Mission Shakti created the most space debris of any ASAT test" → WRONG! China's 2007 FengYun-1C test increased trackable debris by 25% — the largest single debris event. India deliberately chose a low altitude (~283 km) so debris would decay within weeks, not decades. Russia's 2021 test was also more problematic.
Trap 3 — "All space debris is tracked" → WRONG! Only objects larger than ~10 cm in LEO can be tracked by current radar. ~1.2 million fragments larger than 1 cm exist — the vast majority are invisible to tracking. This is why 100% collision avoidance is impossible.
Trap 4 — "Liability Convention 1972 has been successfully used to compensate for orbital collisions" → WRONG! The only successful Liability Convention claim was Canada's $3M from USSR for the Cosmos-954 nuclear satellite crash in Canada (1978) — a surface crash, not an orbital collision. Space-to-space collision liability has never been successfully enforced.
Trap 5 — "India is not a member of IADC or COPUOS" → WRONG! ISRO is a member of IADC (Inter-Agency Space Debris Coordination Committee). India is a FOUNDING member of COPUOS (established 1958, 18 original members). Both give India significant standing in space governance discussions.
Trap 1 — "Kessler Syndrome has already occurred" → WRONG! Kessler Syndrome remains a theoretical risk scenario — NOT yet triggered. However, ESA 2025 warns we are approaching critical thresholds at 550 km altitude. We are at risk, not at syndrome.
Trap 2 — "India's Mission Shakti created the most space debris of any ASAT test" → WRONG! China's 2007 FengYun-1C test increased trackable debris by 25% — the largest single debris event. India deliberately chose a low altitude (~283 km) so debris would decay within weeks, not decades. Russia's 2021 test was also more problematic.
Trap 3 — "All space debris is tracked" → WRONG! Only objects larger than ~10 cm in LEO can be tracked by current radar. ~1.2 million fragments larger than 1 cm exist — the vast majority are invisible to tracking. This is why 100% collision avoidance is impossible.
Trap 4 — "Liability Convention 1972 has been successfully used to compensate for orbital collisions" → WRONG! The only successful Liability Convention claim was Canada's $3M from USSR for the Cosmos-954 nuclear satellite crash in Canada (1978) — a surface crash, not an orbital collision. Space-to-space collision liability has never been successfully enforced.
Trap 5 — "India is not a member of IADC or COPUOS" → WRONG! ISRO is a member of IADC (Inter-Agency Space Debris Coordination Committee). India is a FOUNDING member of COPUOS (established 1958, 18 original members). Both give India significant standing in space governance discussions.
