Did India’s Anti-Satellite Missile Test Endanger The International Space Station?

Even though the target satellite was in an orbit lower than that of the International Space Station did last week’s Project Shakti test generated enough debris to endanger the ISS?

By: Ringo Bones

Last week’s Project Shakti anti-satellite missile test had definitely bolstered India’s space and national defense standing in the world, not to mention Prime Minister Narendra Modi’s poll numbers. But more recently, an announcement by NASA Administrator Jim Bridenstine claims that India’s recent anti-satellite test could endanger other satellites and objects in space – including the International Space Station.

The target of India’s Project Shakti anti-satellite missile last week was believed to be its own spy satellite Microsat-R that was launched a few months ago. The resulting kinetic impact that destroyed the spy satellite created a field of satellite debris at that orbital altitude. The debris now poses a problem because a significant number of it was kicked-up into the same orbital altitude as the International Space Station. In a worse-case scenario, some of the debris could impact the ISS creating a scenario akin to that in the movie Gravity. Some of those pieces are currently too small for NASA to reliably track, meaning we’ll have no way of predicting an impact beforehand. NASA Administrator Bridenstine announced on Monday, April 1, 2019, that “What we are tracking right now, objects big enough to track – we’re talking about 10-cm (4-inches) or bigger – about 60 pieces have been tracked”.

India deliberately targeted a satellite that had a lower orbital altitude than that of the International Space Station to prevent this very sort of situation, but a significant number of the debris appears to have been flung to a higher orbital altitude. Of those 60 debris and objects tracked by NASA, Bridenstine says 24 of them are now at the same altitude as the ISS or higher.

The nature of the region of space in low Earth orbit means that even debris residing above the ISS’ orbit could still pose a threat. Satellites and debris are gradually slowed down by the very thin atmosphere that exists there. The International Space Station, for instance, must routinely fire its booster rockets in order to maintain its orbital altitude and counter the residual atmospheric drag.

Over time, the resulting debris of the recent Indian anti-satellite test would lose altitude and eventually burn up when it hits the denser parts of the Earth’s atmosphere, but the higher altitude debris will have to come down first to within the orbital altitude of the International Space Station posing danger of an impact. The danger of debris impact could still happen months after the test. Even Mainland China’s anti-satellite missile test back in January 11, 2007 still has free-floating debris that could potentially endanger the crew of the ISS.