India's decision to shoot down one of its own satellites in a bid to flex its military space muscle is a "terrible, terrible thing" and not sustainable or compatible with human spaceflight, NASA's highest-ranked official has warned.

Key points: India's anti-satellite test created about 400 pieces of orbital debris, NASA says

India's anti-satellite test created about 400 pieces of orbital debris, NASA says NASA's administrator said it was unacceptable for nations to create debris fields that "put at risk our people"

NASA's administrator said it was unacceptable for nations to create debris fields that "put at risk our people" India has sought to downplay any risk posed by debris from its missile test

Scientists shot down a live satellite 300 kilometres from Earth with a ground-to-space missile on Wednesday, in what Indian Prime Minister Narendra Modi hailed a "breakthrough" for anti-satellite weaponry.

India's foreign ministry sought to downplay any risk of debris from the missile test, saying the impact occurred in low-Earth orbit and remnants of the satellite would "decay and fall back on to the Earth within weeks".

But NASA administrator Jim Bridenstine, the US space agency's highest-ranked official, said the anti-satellite test created about 400 pieces of orbital debris.

Sixty of those were big enough for the agency to track, he said, and 24 rose higher than the International Space Station's orbit around Earth.

"That is a terrible, terrible thing to create an event that sends debris in an apogee that goes above the International Space Station," Mr Bridenstine told a town hall meeting live-streamed on NASA TV.

"And that kind of activity is not compatible with the future of human spaceflight that we need to see happen."

Although the debris is low enough in Earth's orbit to dissipate, Mr Bridenstine said, it was critical authorities tracked the remnants to ensure there was no risk to those in space.

He said it was unacceptable for nations to "create orbital debris fields that put at risk our people".

"We need to be clear, also, that these activities are not sustainable or compatible with human spaceflight," he said.

'We all live in space, let's not make it a mess'

Experts say anti-satellite weapons that shatter their targets create a cloud of fragments that can collide with other objects, potentially setting off a chain reaction of projectiles moving through Earth's orbit.

Acting US Defence Secretary Patrick Shanahan last week warned any nations contemplating anti-satellite weapons tests risked making a "mess" in space because of the debris fields left behind.

"My message would be: we all live in space, let's not make it a mess," he told reporters.

"Space should be a place where we can conduct business. Space is a place where people should have the freedom to operate."

India is the fourth country to have used an anti-satellite weapon, following the United States, Russia and China.

China destroyed a satellite in 2007, creating the largest orbital debris cloud in history, with more than 3,000 objects, according to the Secure World Foundation.

Anti-satellite weapons permit attacks on enemy satellites, blinding them or disrupting communications, as well as providing a technology base to intercept ballistic missiles.

Such capabilities have raised fears of the weaponisation of space and a race between rivals.

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ABC/Reuters