New Delhi: Four months after India successfully tested its anti-satellite (ASAT) capabilities, experts tracking the debris created by the event have reported that 40% of it has still not decayed. India had claimed after the test that the debris would decay within 45 days after the event.

After NASA administrator Jim Bridenstein claimed that debris from the ASAT test threatened the International Space Station (ISS), India denied the claim. Chairman of Defence Research Development Organisation (DRDO) Satheesh Reddy said the mission, codename Shakti conducted on March 27, was carefully planned to minimise the amount of debris generated, adding that it would decay within 45 days.

However, experts tracking the debris have found that not to be the case. In mid-June, as The Wire reported, one of those experts Marco Langbroek, claimed that “92 larger debris pieces from the test” had been catalogued and that half of them “were still orbiting”.

Now, another expert, Jonathan McDowell, has found that 122 days after the test, 39 of 101 catalogued objects are still in orbit. This means that around 40% of the debris is still in orbit.

On Twitter, he posted a chart tracking the orbit decay plot of the debris generated.

Updated orbit decay plot of the Indian antisatellite debris, at event plus 122 days pic.twitter.com/3EQyRXYPgU — Jonathan McDowell (@planet4589) July 27, 2019

In another tweet, McDowell said that the highest object is expected to stay in orbit “till next spring”.

I haven’t done drag calculations.

The highest object is in a 277 x 1889 km orbit. Guessing it will be up till next spring. — Jonathan McDowell (@planet4589) July 27, 2019

The ASAT test was conducted at an altitude of about 300 km, where it would not endanger any other satellite, the explosion pushed fragments into the upper reaches of the low-Earth orbit. This led NASA to warn that the ISS could be threatened by the debris, apart from other experts also raising concerns.

In May, Longbroek wrote in a blog post that the mission was “conducted in a less responsible way than originally claimed.” Some of the debris generated by test had much longer orbital lifetimes – in come cases up to 10-times longer, he wrote.

These fragments ended up at much higher altitudes than what the Indian government has been willing to admit, thus becoming a potential threat to satellites in all orbital inclinations at these altitudes.

Also Read: India’s ASAT Capability Has Been Around for Some Time Now

The missile that was tested is a three-stage rocket and has a range of up to 1,000 km. This allows it to target most low-Earth orbit satellites. As The Wire has reported, Reddy stated that the test was conducted to intercept a satellite at about 280 km to minimise the threat of space debris. The missile has the ability to target satellites travelling at over 7.5 km/s (with relative velocities around 10 km/s for satellites in low-Earth orbit).

Reddy also said the entire operation, from identifying the satellite, launching the missile to tracking and destroying it, was automated because of the high precision and control demand.