ISRO averts multiple collision threats: NISAR, Chandrayaan-2 face close orbital encounters amid rising space debris

The Indian Space Research Organisation (ISRO) has revealed a stark reality of modern space operations: Earth’s orbit is becoming increasingly crowded and hazardous. According to the Indian Space Situational Assessment Report (ISSAR) 2025, the number of objects in orbit continues to surge, driven by unprecedented global launch activity and satellite deployments. In 2025 alone, 4,651 objects were placed in orbit, showing the scale of congestion.

“A total of 4651 objects were added to the space object population in this year in a significant rise compared to the previous years- the space object population increased by 2963 objects from 254 launches in 2024 and 3135 objects from 212 launches in 2023 ”, the report noted.

This congestion has led to a sharp rise in “close approach alerts”, warnings issued when two objects come dangerously near each other. ISRO noted that such alerts are now frequent, reflecting what it described as an “alarmingly rising congestion” in low-Earth orbit. The situation is compounded by space debris travelling at speeds of nearly 28,000 km/h, where even minute fragments can threaten operational satellites.

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Collision avoidance and critical interventions

Against this backdrop, ISRO has had to actively manoeuvre its satellites to prevent disasters. The report confirms that multiple collision avoidance manoeuvres (CAMs) were executed, including fourteen in low-Earth orbit and four in geostationary orbit, a total of 18. Earlier data also showed that ISRO successfully averted ten potential collisions in a single year, highlighting the scale of the threat. In a recent press release, PIB wrote that a total of 129 trackable space debris originating from Indian satellite missions are in orbit.

Cumulative number of CAMs performed since 2011 Photograph: (ISRO)

Significantly, key missions such as NISAR and Chandrayaan-2 experienced close calls in orbit, requiring timely intervention. NISAR, a joint NASA-ISRO Earth observation mission launched on July 30, 2025, and the Chandrayaan-2 Orbiter both faced potential risks from nearby objects. For Chandrayaan-2, ISRO carried out 16 trajectory corrections to maintain safety, with two instances requiring revised plans to better avoid close approaches. These manoeuvres are precisely calculated to protect satellites without affecting mission objectives.

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ISRO’s space situational awareness programme continuously tracks thousands of objects, issuing alerts and assessing risks in real time. As the agency states, this capability is essential “to protect national space assets from hazards”, including debris and inactive satellites.

The report also said, “Out of the 10749 Starlink satellites, 9396 satellites were still in orbit and 1353 satellites re-entered the Earth’s atmosphere by the end of 2025.”

Strategic response to a growing threat

The findings underline a broader challenge: orbital sustainability. With over 140 Indian satellites, many in the most crowded low-Earth orbit, the risk of collision is structurally higher. To address this, ISRO is strengthening indigenous systems such as Project NETRA, designed to track and predict debris movement.

The report ultimately serves as both a progress update and a warning. While ISRO’s timely interventions have prevented catastrophic collisions, the increasing density of space traffic signals an urgent need for global coordination, improved tracking systems, and stricter debris mitigation practices.