India should build its own observation capability to prevent collision with satellites in crowded orbit, says ISRO Chief

Speaking at an event in Delhi, Somanath said that another mission also planned for this year will attempt tethered capturing — where a robotic arm on the upper stage of a launch vehicle will capture a moving satellite and collect it. He said ISRO is also working on developing a service module that will be able to refuel a satellite allowing it to be fired or brought down from orbit.

With an increasing number of satellites and debris in low earth orbit, he said India needed to create its own observation capability for situational awareness, which is tracking the size, velocity, and movement of objects in orbit to prevent collision with satellites or upper stages of launch vehicles.

“Unless you have strong observational capability, there’s no point in working in space situational awareness… while we have perfected our mathematical prediction capability, we need to improve our observational capability,” he said.
Without strong observational capability, he said, a country will depend on others for orbital data, believe it’s correct, and think that their satellites are safe, which might not always be true.

Space situational awareness might require several technologies including radars, optical telescopes, radio telescopes, geo-locating sensors, lasers, space weather forecasting sensors, and even sensors on-board other satellites.
There are about 40,500 debris items above the size of 10 cm, 1.1 lakh objects of sizes ranging from 1m to 10 cm, and 130 million objects of sizes 1mm to 1 cm that are currently tracked in space.

Objects between 1cm and 10 cm size pose a bigger challenge, Somanath said, as debris shielding cannot handle them for being big enough, but at the same time, those are too small to be tracked easily. Batting for automated collision avoidance manoeuvre, Somanath said that even with just over 50 satellites, India needed to perform 100 collision avoidance manoeuvres over the last one year.