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1.5 lakh collision alerts for Indian satellites in 2025

April 17, 2026 4 min read Science & Technology GS3 (Science & Technology Space)
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What Happened

  • India's Indian Space Situational Awareness Report (ISSAR) 2025 revealed that ISRO's Earth-orbiting satellites received over 1.5 lakh (150,000) close-approach collision alerts in 2025, up from 1.38 lakh in 2023.
  • In response, ISRO performed 18 Collision Avoidance Manoeuvres (CAMs) in 2025 — 14 for Low Earth Orbit (LEO) satellites including one for NISAR, and 4 for Geostationary Earth Orbit (GEO) satellites.
  • The alerts are issued by the Combined Space Operations Centre (CSpOC) of the US Space Command, which tracks space objects globally.
  • The surge in alerts reflects the growing congestion of orbital space, driven by the proliferation of commercial mega-constellations and decades of accumulated debris.
  • ISRO has announced an ambition to achieve zero orbital debris by 2030 and has been investing in indigenous Space Situational Awareness (SSA) infrastructure.

Static Topic Bridges

Space Situational Awareness (SSA) and Space Traffic Management

Space Situational Awareness refers to the comprehensive knowledge of the space environment — the location, orbital parameters, and status of all tracked man-made and natural objects in space. SSA is foundational to ensuring satellite operations remain safe in an increasingly congested orbital environment.

  • The US Space Surveillance Network tracks approximately 45,000 objects larger than 10 cm in Low Earth Orbit (LEO); an estimated 130 million fragments smaller than 1 cm remain untracked but are capable of damaging satellites.
  • India's ISRO operates the Multi Object Tracking Radar (MOTR) at SHAR (Satish Dhawan Space Centre) and optical telescopes to build indigenous SSA capability.
  • A Collision Avoidance Manoeuvre (CAM) involves firing onboard thrusters to shift a satellite's orbital path when the probability of collision with a tracked object exceeds an acceptable threshold.
  • Space Traffic Management (STM) is the emerging international governance framework for coordinating orbital slots and collision-avoidance protocols, analogous to air traffic control.

Connection to this news: The 1.5 lakh alerts and 18 CAMs demonstrate that SSA is no longer a theoretical concern — it is operationally critical for India's growing fleet of Earth observation, communication, and navigation satellites.

Kessler Syndrome and the Space Debris Problem

The Kessler Syndrome, theorised by NASA scientist Donald Kessler in 1978, describes a cascading scenario: if orbital debris density exceeds a critical threshold, collisions between objects generate more fragments, which cause more collisions in a self-sustaining chain reaction that renders entire orbital shells unusable.

  • Currently approximately 36,500 objects larger than 10 cm, 1 million objects 1–10 cm, and over 130 million objects smaller than 1 cm orbit Earth.
  • Spent rocket bodies constitute roughly 50% of the total debris mass in LEO — they are the most dangerous category because of their large size and residual fuel that can cause explosions.
  • The IADC (Inter-Agency Space Debris Coordination Committee) published the first Space Debris Mitigation Guidelines in 2002, establishing the "25-year rule" — satellites must de-orbit within 25 years of end-of-mission.
  • The UN Committee on the Peaceful Uses of Outer Space (COPUOS) adopted the IADC guidelines in 2007.

Connection to this news: The increasing frequency of collision alerts for Indian satellites signals that orbital congestion is worsening; without debris mitigation, future missions risk a cascade effect affecting India's space assets and strategic capabilities.

India's Space Programme and Policy Framework

India's space programme is governed by the Indian Space Policy 2023, which opened the sector to private players through IN-SPACe (Indian National Space Promotion and Authorisation Centre) while retaining ISRO as the lead agency for strategic and research missions.

  • India has approximately 50+ operational satellites across LEO, Medium Earth Orbit (MEO), and GEO.
  • Key current missions include the EOS series (Earth Observation), GSAT series (communication), NavIC (navigation), and the upcoming NISAR (NASA-ISRO Synthetic Aperture Radar) — a joint India-US Earth science satellite.
  • India's Space Debris Research and Mitigation Centre (SD-RMC) at ISRO Headquarters coordinates debris tracking and mitigation.
  • Project NETRA (Network for Space Objects Tracking and Analysis) is India's dedicated space situational awareness initiative.

Connection to this news: NISAR's CAM in 2025 underscores the vulnerability of high-value, billion-dollar joint missions to the debris environment, making robust SSA a strategic imperative for India.

Key Facts & Data

  • 1,50,000+ close-approach alerts received by Indian satellites in 2025 (up from 1,38,000 in 2023)
  • 18 Collision Avoidance Manoeuvres (CAMs) performed by ISRO in 2025: 14 LEO + 4 GEO
  • ISRO's target: zero orbital debris by 2030
  • IADC 25-year de-orbit rule applies to LEO satellites
  • Long Period Average (LPA) used in SSA: US Space Surveillance Network tracks 45,000+ objects above 10 cm
  • ISSAR 2025 (Indian Space Situational Awareness Report) is the primary reference document