One Facility, Two Skies: Why ISRO's Chandrapur Radar Watches Both Space Debris and Northeast Storms

A Lighthouse That Also Reads the Weather

Here's what's actually happening. Thousands of objects circle the Earth: working satellites, dead ones, spent rocket stages and fragments from old collisions. Each moves at several kilometres per second. If one is heading toward an Indian satellite, ISRO needs to know days in advance, so it can fire thrusters and move its satellite out of the way.

That warning system is called Space Situational Awareness or SSA. SSA has three steps:

• Detect an object, using radars and optical telescopes.
• Predict its future path by calculating its orbit.
• Warn the satellite operator if two paths will come dangerously close. The first step is where the sensors sit and that is what the Chandrapur facility adds.

Why it matters whose radar it is ISRO has never been blind.

It runs a control centre for space operations safety, IS4OM in Bengaluru and carries out regular proximity checks. It carried out 19 collision avoidance manoeuvres in 2021 and 10 in 2024. But its 2024 assessment report notes that many of its proximity alerts were generated in collaboration with US Space Command.

That works well in normal times. The weakness is about control: a country that relies on another country's catalogue sees what that partner tracks and shares, on that partner's schedule. Project NETRA exists to build India's own network of radars and telescopes so the detect-and-predict steps can increasingly happen on Indian data.

One facility does not end that dependence. A tracking network needs sensors spread across many locations so objects are observed more often. Chandrapur is one more piece of a network that is still being built.

The second sky The less obvious part of this story is what the facility does when it is not watching orbit.

ISRO says the same facility will support atmospheric and ionospheric observation, cloud and weather monitoring and space-weather studies. On the ground, that means flash-flood warnings, thunderstorm and lightning nowcasting and aviation guidance.

That is why the location matters. The Northeast faces regular floods and violent pre-monsoon storms. A facility built mainly for strategic space tracking also becomes part of the region's disaster-warning system. The lighthouse analogy has a limit.

Tracking a small object hundreds of kilometres up and measuring rain in a nearby cloud are very different radar tasks. They may use different equipment, frequencies or operating modes. The reports do not give the radar type, frequency band, cost or completion date.

The accurate claim is that one site and one institution serve both purposes, not necessarily that one radar beam does both jobs at once.

Where

India stands The United States runs the most extensive space surveillance network and publishes a widely used public catalogue. India is building toward its own capability: an operational safety centre, annual situational assessment reports and now new NETRA sensors.

It is not yet at parity, but it is steadily reducing its dependence on others. For the exam, the insight is that India's SSA strategy is dual-use by design. The same investment that protects satellites worth thousands of crores also serves farmers, pilots and flood-prone districts in Assam.

That helps justify the cost to the public and it gives the facility value even in years when no debris alert ever arrives.