The head of NASA, administrator Jim Bridenstine, has called a recent Indian anti-satellite missile test, which destroyed a satellite in low Earth orbit and blasted 400 pieces of debris into space, a "terrible, terrible thing".

"That kind of activity is not compatible with the future of human spaceflight," said Bridenstine, speaking at a livestreamed Town Hall gathering of NASA employees. "It's unacceptable and NASA needs to be very clear about what its impact to us is."

India announced that it had successfully carried out "Mission Shakti", an anti-satellite missile test on March 27, destroying one of the country's satellites. The success of the mission made India only the fourth nation to complete such a test, following previous tests conducted by the US, Russia and China.

In the official press release, India's Ministry of External Affairs stated the test was carried out in the "lower atmosphere" to ensure there were no space debris and even if there were debris generated, it would fall back to Earth within weeks -- but the debris field may still be dangerous.

"Claims that destructive events like this are fine because the fragments will soon be incinerated are deliberately misleading, in my opinion," says Alice Gorman, an Australian space archaeologist and debris expert. "Any fragmentation event, whether intended or accidental, increases the risks of collision with functioning satellites."

During the NASA Town Hall, Bridenstine noted that India's satellite destruction created over 400 pieces of debris and NASA is currently tracking 60 of those. A subset of those actually swing into an orbit above the ISS, potentially endangering the station and the astronauts within if it were to collide with the station.

"The risk to the International Space Station was increased by 44 percent," said Bridenstine.

Notably, the station does have emergency procedures in place, should NASA spot junk headed straight for the space base. Generally, the crew members jump into the "lifeboats" on the station: the capsules that provide them passage to and from Earth. If the station were hit, they could be jettisoned off. Fortunately, while the astronauts aboard have taken refuge in the capsule before, they've never had to be evacuated.

As for the recent satellite destruction, it's unlikely such a scenario would occur.

"The good thing is it's low enough that in Earth orbit that over time this will all dissipate," Bridenstine said, contrasting this incident with a 2007 Chinese anti-satellite test which created a debris field that is still circling the Earth.

Several companies have been working on ways to reduce the potentially dangerous space debris field that is accumulating around the Earth, including using a harpoon to stab at space junk or a net to snare it like a space Spider-Man. The worry is that, as low Earth orbit fills with junk, an unstoppable cascade of destruction might occur, should debris strike the wrong satellite. The so-called "Kessler Syndrome" would see satellites and space infrastructure constantly torn apart by a rolling wave of debris.

While nations are free to destroy their own assets in space, deliberately creating a debris field is a simple show of power, designed to show other nations their satellite-destroying capabilities. Gorman says "there is no good scientific reason for such tests" to take place.

"They are purely and simply a visible demonstration of power," she says.

The good news is that, for now, Bridenstine says there is little danger to the station and the astronauts within.

"While the risk went up 44 percent, our astronauts are still safe, the International Space Station is still safe," Bridenstine explained. Were the ISS to run into any trouble, it could be maneuvered in such a way that it avoids any potential collisions.

"At the end of the day we have to be clear also that these activities are not sustainable or compatible with human spaceflight."