More than four months after India destroyed one of its own satellites in space, dozens of pieces of debris from the cataclysmic event still circulate in orbit, posing a small but potential threat to other functioning spacecraft that might pass close by. It’s possible that some of this debris could stay in orbit for a full year before falling back down to Earth, according to space trackers.

On March 27th, India fired a ground-based missile at a test satellite the country had launched in January, demonstrating the capability to take out a spacecraft in Earth orbit. Destroying an orbiting satellite is no easy feat, as these vehicles are relatively small and zoom above our planet at thousands of miles per hour. Hitting one directly with a missile takes a lot of precision, and it sends a message that a country can take out a perceived hostile satellite if necessary.

anti-satellite, or ASAT, tests come with a cost

However, these types of demonstrations, known as anti-satellite, or ASAT, tests come with a cost. India’s test, known as “Mission Shakti,” broke the satellite apart into hundreds of pieces of debris that have since been tracked by the United States Air Force. These pieces are still moving at thousands of miles an hour around Earth and cannot be controlled by anyone on the ground. If the debris were to collide with another satellite at such high speeds, it could do significant damage and potentially render a spacecraft inoperable.

Earth orbit is already a fairly congested place, filled with more than 22,000 pieces of debris and objects larger than a softball, according to the European Space Agency. All of these materials are tracked by the US Air Force’s 18th Space Control Squadron. But ASAT tests further contribute to this traffic and might even create pieces of debris that are too tiny to track.

India did try to minimize the effects of the test by targeting a satellite that was in a relatively low orbit above Earth — just 186 miles (300 kilometers) up. So most of the debris created from the event got pulled down to Earth relatively quickly and burned up in our planet’s atmosphere. One Indian official argued that the debris would be gone within 45 days of the test. “That’s why we did it at lower altitude, it will vanish in no time,” said G. Satheesh Reddy, the chief of India’s Defence Research and Development Organisation, according to Reuters.

The Air Force acknowledges that most of the debris is gone. “We can confirm more than 300 of the 400 plus objects we tracked from this event have reentered the Earth’s atmosphere,” Maj. Cody Chiles, a public affairs officer for the Air Force’s Joint Force Space Component Command, which oversees the 18th Space Control Squadron, tells The Verge. But the collision caused some pieces to jump to higher orbits than the original satellite, and it even put pieces in the same general path as the International Space Station, which orbits at 250 miles (400 kilometers) and currently has six astronauts on board.

the collision caused some pieces to jump to higher orbits than the original satellite

That’s just the nature of these kinds of tests, according to Jonathan McDowell, an astrophysicist at Harvard who has been tracking the debris with data from the Air Force. “The bulk of the debris reentered [the atmosphere] immediately — within minutes,” he tells The Verge. “But there was always going to be a significant amount — a lot less than what came down, but still enough to be annoying — that would go up instead.”

This has drawn strong criticism from NASA’s administrator Jim Bridenstine. “That is a terrible, terrible thing, to create an event that sends debris into an apogee that goes above the International Space Station,” he said at a NASA town hall. “And that kind of activity is not compatible with the future of human spaceflight.” Many companies within the aerospace community also condemned India’s ASAT test, citing potential danger to spacecraft in orbit.

Now, more than 130 days later, there are still more than 50 pieces of debris from India’s ASAT test currently being tracked by the US Air Force, according to Maj. Chiles. NASA has also reportedly confirmed the persistence of the debris in orbit, according to the Space Intel Report. Some of the debris was even added to the catalog this week, meaning there was not enough data to get a good idea of where these pieces were orbiting up until now. And many are still crossing paths with the space station’s orbit. In fact, some of these pieces are reaching altitudes as high as 1,000 miles up, according to McDowell’s analysis.

The 18th Space Control Squadron says it won’t speculate on when all of the debris will come back down to Earth. But McDowell speculates that it should come down over the next couple of years. “Based on the current decay rates of some of these higher orbit objects, I think there will be at least some debris up for another year,” he says. “But probably not for two years.”

“The probability of any of the debris hitting anything is small, but it’s just so unnecessary.”

Ultimately, McDowell says this whole ordeal demonstrates that there is no such thing as a “safe” ASAT test. No matter what, these things are messy, something the United States also learned when it shot down its own failing satellite in 2008 during a mission known as Operation Burnt Frost. That demonstration also created hundreds to thousands of pieces of debris, some of which jumped into higher orbits than that of the original satellite.

Operation Burnt Frost didn’t lead to the destruction of any other satellites, and it’s doubtful that India’s Mission Shakti will harm any other spacecraft either. Still, many within the aerospace community don’t want this kind of behavior to become normalized. “The probability of any of the debris hitting anything is small, but it’s just so unnecessary,” says McDowell. “Yes, there’s other debris around even at those altitudes, but you’re increasing the amount of debris for no good reason.”