“It's unacceptable,” Bridenstine said when asked about India's successful anti-satellite test during a town hall event.
“That is a terrible, terrible thing to create an event that sends debris in an apogee that goes above the International Space Station," Bridenstine said. "That kind of activity is not compatible with the future of human space flight."
As a result of India's test, the risk of a small debris impact to the ISS increased by 44 percent over a period of ten days, according to NASA.
On Wednesday, Indian Prime Minister Narendra Modi announced that New Delhi had successfully tested its first indigenous anti-satellite missile by hitting a defunct Indian satellite at an altitude of 300 kilometres (186 miles).
Modi said India became the fourth country in the world to possess such a weapon after China, Russia and the United States.