The U.S. Just Admitted it Has Weapons in Space. Here’s Why That’s a Big Deal

The biggest danger, however, comes from missiles and orbital projectiles that would effectively blow satellites up, since that kind of kinetic attack produces a swirling cloud of orbital debris that would fan out from the site of the strike, threatening other satellites with unplanned destruction. Accidental collisions with space junk already worry both the commercial and military sectors. There are currently nearly 15,000 operational satellites in Earth orbit, and up to 10,000 defunct ones, making for a lot of celestial traffic. Just as troubling, according to NASA’s Orbital Debris Program Office, there are an additional 500,000 objects measuring 1 to 10 cm (.39 in. and 3.9 in.), and 100 million in the 1-mm range. Such tiny bits of mass matter. Traveling at 4.85 miles per second, even a fleck of paint could do significant damage to a satellite, or, worse, a crewed spacecraft.

What truly keeps space planners up at night is something known as the Kessler Effect—a slow-motion chain reaction in which the flotsam produced by a collision with even a single piece of space debris could strike other satellites, producing more debris still, and more collisions still, ultimately leading to the loss of all spacecraft in that orbital band. A runaway Kessler effect was the premise of the 2013 film Gravity, and while the screenwriters took liberties with the science (the collisions all played out within hours when in fact they could take months or even years), the eventual results would be the same. China’s 2007 satellite-destruction exercise was estimated to have produced more than 3,000 pieces of debris—which could have taken out the country’s own spacecraft as readily as those of rivals. Russia’s similar duck-hunting in 2021 is estimated by the Pentagon to have produced 1,500 fragments. It was luck more than anything else that prevented either move from setting a Kessler cascade in motion.