Project NETRA is ISRO's network of radars, telescopes and a control centre that tracks objects in space so Indian satellites can avoid collisions.
Satellites cannot see what is coming at them. Someone on the ground has to watch the sky, work out each object's orbit and warn operators. This job is called space situational awareness, or SSA. NETRA — short for NEtwork for space object TRacking and Analysis — is ISRO's project to build this capability in India. Today most of the close-approach alerts ISRO studies still come from the US Space Command's tracking network.
The first piece, ISRO's SSA Control Centre, was inaugurated by then ISRO Chairman K. Sivan on 14 December 2020 at the ISTRAC campus in Peenya, Bengaluru. ISRO describes it as the hub of all SSA activity in India. Its jobs include:
The centre also has labs for debris mitigation, for checking compliance with UN and IADC debris guidelines, and for research on break-ups, micrometeoroids, space weather and near-Earth asteroids.
The project's other parts are sensors. ISRO's 2024 report says a radar is being set up at Chandrapur in Assam and an optical telescope at Hanle in Ladakh. At Sriharikota, the Multi-Object Tracking Radar has been refurbished; where possible it follows Indian rocket bodies and satellites in their final orbits before re-entry.
Each year ISRO publishes the Indian Space Situational Assessment Report (ISSAR), compiled by its IS4OM system for safe and sustainable space operations. The 2024 edition shows the scale: more than 53,000 alerts analysed, 10 avoidance manoeuvres, and 9 Indian satellites re-entering during the year. It also keeps watch on old Indian debris, such as the 41 fragments of the 2001 PSLV-C3 stage break-up that were still in orbit at the end of 2024.
Pick any Indian satellite in low orbit: it is one of the spacecraft ISRO screens against tens of thousands of close-approach alerts every year. Browse India's satellites
ISRO lists the control centre's processing chain: observations come in, are correlated with known objects, used for orbit determination and added to a catalogue. From the catalogue, future positions are predicted and screened against ISRO's satellites and launch vehicles.
The screening load is large. In 2024 ISRO's satellites carried out 681 orbit manoeuvres in low Earth orbit and 504 in geostationary orbit, not counting 1,222 small pulsing manoeuvres, plus 21 in deep space. Every planned burn is itself checked after planning; in 2024 that check led to 89 revised LEO plans and 2 revised GEO plans. Compare that with only 10 dedicated avoidance manoeuvres. ISRO credits a larger conjunction screening volume and more accurate ephemerides (predicted positions) for letting it fold avoidance into routine orbit-maintenance burns instead.
Launches are screened too. This launch collision-avoidance (COLA) analysis fixes the exact lift-off time. All five 2024 launches from Sriharikota were cleared this way — PSLV-C58 for 03:40 UTC on 1 January, for example — and PSLV-C60 was held 2 min 15 s.
A simple ratio shows why better data matters: 53,000 alerts ÷ 10 manoeuvres ≈ 5,300 alerts per real burn. Acting on every alert would waste fuel and shorten satellite lives; ignoring a real one could end a mission.
NEtwork for space object TRacking and Analysis. It is ISRO's space situational awareness project to track objects in orbit and protect Indian satellites from collisions.
At the ISTRAC campus in Peenya, Bengaluru. It was inaugurated on 14 December 2020.
The Indian Space Situational Assessment Report, ISRO's yearly report on the space environment, close approaches, re-entries and India's debris-mitigation work.