Six months after India's ASAT test

Six months ago today, on 27 March 2019 at 5:42:15 UT, India conducted its first successful Anti Satellite (ASAT) Test, under the code name Mission Shakti. I wrote an in-depth OSINT analysis of that test published in The Diplomat in April 2019.

Part of that analysis was an assessment - also discussed in various previous posts on this blog - on how long debris from this ASAT test would stay on-orbit. Half-a-year after the test, it is time to make a tally of what is left and what is gone - and make a new estimate when the last piece will be gone.

A few more debris pieces have been catalogued by CSpOC since my last tally. As of 27 September 2019, orbits for 125 debris pieces from the ASAT test have been catalogued. Of these 125 objects, 87 (or 70%) had reentered or had likely reentered by 27 September, leaving 38 (or 30%) still on orbit.

click diagram to enlarge

click diagram to enlarge

Remember that the Indian DRDO had made the claim that all debris would have reentered 45 days after the test. This is clearly not correct: of the well-tracked debris for which we have orbits (presumably there is a lot more for which we have no orbits), only 29%, i.e. barely one-third, reentered within 45 days. Over 70% did not. At 120 days after the test, only half of the catalogued population of larger debris had reentered.

click diagram to enlarge

click diagram to enlarge

I used SatEvo to produce reentry estimates for the 38 objects still on orbit on 27 September 2019. By the end of the year, some 15 to 16 of these larger debris fragments should still remain on-orbit.

One year after the test, at the end of March 2020, about 90% of all tracked debris should have reentered. The last or the tracked debris fragments for which we have orbits, might not reenter untill mid 2024.

The current apogee altitudes of the objects on-orbit spread between 270 and 1945 km. They have now well-dispersed in RAAN too, no longer sharing the same orbital plane:

click to enlarge

click to enlarge

Some 90% of the debris fragments still on-orbit have an apogee altitude above that of the ISS, meaning that they almost all have orbits that reach well into the orbital altitudes of operational satellites.