During a meeting with NASA employees on April 1, NASA Administrator Jim Bridenstine delivered sharply critical remarks about India’s March 27 anti-satellite weapons (ASAT) test. Bridenstine said that some of the larger debris from the collision of the ground-launched missile and the Microsat-R satellite had been thrown into orbits that could pose a danger to the International Space Station (ISS).
The “Mission Shakti” ASAT shot hit the Microsat-R Earth observation satellite at an altitude of about 300 kilometers—an altitude Indian officials said would pose little risk to other spacecraft. But Bridenstine said that some of the debris created by the test had been thrown into orbits with a much higher apogee. In some cases, he said, those orbits could cross the track of the ISS, which orbits at an altitude of 410 kilometers.
Of the 400 pieces of debris that had been identified by NASA, Bridenstine said, 60 were large enough to be tracked by the US Air Force’s Space Surveillance Network and US Strategic Command’s Combined Space Operations Center. ”Of those 60, we know that 24 of them are going above the apogee of the International Space Station,” he continued. Calculations by NASA and DOD after the test found that the risk of debris striking the space station went up by 44 percent over a ten-day period following the test, Bridenstine told NASA employees.
“That is a terrible, terrible thing, to create an event that sends debris in an apogee that goes above the International Space Station,” Bridenstine declared. “And that kind of activity is not compatible with the future of human spaceflight that we need to see happen. We are charged with commercializing low Earth orbit. We are charged with enabling more activities in space than we’ve ever seen before, for the purpose of benefiting the human condition… all of those are placed at risk when these kinds of events happen. And if one country does this, then other countries feel they have to do it, too. It’s unacceptable, and NASA needs to be very clear about what its impact to us is.”
Bridenstine placed the actual risk of a collision much lower, saying that the ISS’ crew was not at risk because the space station could be maneuvered if necessary. ”The probability of that, I think, is low,” he said. But the test was still irresponsible, he said—a much stronger rebuke than any delivered officially by the US to Indian officials.
Analytical Graphics has posted a video showing a simulated breakup of Microsat-R based on initial data from US Strategic Command. The model shows a tail of debris pushed into an orbit with a higher apogee, while other debris scatters at lower velocity in a lower, more quickly decaying orbit. Most of the debris field should re-enter the atmosphere within a month, but some may remain a hazard for years to come. A similar ASAT test by China in 2007 created a debris field of more than 3,000 objects in low Earth orbit—some of which passed within six kilometers of the ISS in 2011. As of 2016, there were still nearly 3,000 trackable pieces of debris still in orbit—more than nine years after the test.