The amount of Indian space debris may have almost doubled in the aftermath of the Mission Shakti anti-satellite strike but this is still significantly less than the existing space debris generated by China, Russia and the United States.
Data from SPACE-TRACK.org, a public access repository maintained by the U.S. defence wing that tracks space activity, notes only 80 pieces of “space debris” attributable to India in orbit.
This, however, doesn’t include debris from MICROSAT-R, the DRDO satellite that was pulverised by India’s anti-satellite missile.
NASA on Monday criticised India for the test, describing it as a “terrible, terrible” thing that had endangered the International Space Station (ISS) and led to the creation of nearly 400 pieces of orbital debris.
NASA administrator Jim Bridenstine said some of the debris posed a risk to astronauts on board the ISS. Mr Bridenstine said of the nearly 400 pieces, only 60 were being tracked and 24 of them were going above the apogee of the ISS (the farthest point from the earth of the ISS’ orbit). The latter posed the maximum risk to the ISS, he said.
Prior to the March 27 test, for India’s 80 pieces, there were 4,091 pieces of debris by the U.S., 4,025 by Russia and China’s 4,038, according to SPACE-TRACK.
Orbital debris are tracked by a variety of ground-based radar and space stations. The speeds at which these objects — between 1mm to 10 cm across — hurtle through space travel makes them extremely dangerous, various studies have showed.
That said, the International Space Station is among the most fortified space objects. It has debris shields deployed around the crewed modules, each composed of two metal sheets, separated by about 10 cm. The outer bumper shield exploits the impact energy to shatter the debris object, such that the inner back wall can withstand the resulting spray of smaller-sized fragments.
Between the walls, fabric with the same functionality as in bullet-proof vests is deployed. This design enables the shield to buffer against debris objects up to 1 cm in size.
The U.S. Space Surveillance system can calculate if an object will veer too close to the ISS and — if need be — the station can be moved out of the orbit of the offending projectile. By the end of 2012, the Station had performed more than 15 of these manoeuvres, according to the ESA.