Tracking Space Trash

Last April, a 19-year-old in Naples, Florida, heard a huge crash and his house shook. His dad, Alejandro Otero, called the police. They found a hole in the roof and a hunk of partially melted metal in the floor. A piece of space junk had struck their house!

Space trash crashing into Earth is rare. But at least 25,000 pieces of junk larger than 4 inches are in orbit right now. It's mostly old satellites and other debris from decades of space exploration. Most of this space junk will slowly fall toward Earth and burn up in the atmosphere. But larger objects—like the one that hit the Oteros’ house—will fall to the ground.

This junk is also more dangerous for astronauts and satellites still in use. All objects orbiting Earth travel at speeds of about 17,500 miles per hour. A collision with a large piece of debris could be catastrophic! So NASA and the military work together to track the debris that threaten active satellites.

Last April, a 19-year-old in Naples, Florida, heard a crash. His house shook. His dad called the police. When they arrived, they found a hole in the roof. There was a hunk of metal in the floor. A piece of space junk had struck the house!

Space trash doesn’t often crash to Earth. But it can happen. At least 25,000 pieces of junk are in orbit right now. And that’s only the pieces bigger than 4 inches! Most of them are old satellites and other debris left by space exploration. They usually slowly fall toward Earth and burn up in the atmosphere. But larger objects can fall to the ground. That’s what happened to the house in Florida.

In space, floating junk can hit active satellites. This puts astronauts in danger. Objects orbit Earth at about 17,500 miles per hour. Colliding with a large piece of debris could be catastrophic! So NASA and the military work together to track space junk.

Avoiding space trash is crucial for the International Space Station (ISS), which is the largest satellite in space. “Twenty-four hours a day, it’s someone’s job to protect the ISS from orbital debris,” says Shane Cowen, an orbital analyst who works with NASA to track the ISS (see Protecting the “Pizza Box,” below).

In fact, 95 percent of space trash is too small to be tracked. NASA estimates that more than 100 million pieces of space debris are smaller than 1 centimeter. This tiny space junk includes everything from flecks of paint to stray screws. Most of it is from existing junk smashing into even smaller pieces.

Although large space trash hitting Earth is extremely rare, Cowen says that “the more objects there are in space, the more chance there is to interfere with satellite communications.”

Avoiding space trash is important for the International Space Station (ISS). It’s the largest satellite in space. Astronauts live on it. “Twenty-four hours a day, it’s someone’s job to protect the ISS from orbital debris,” says Shane Cowen. He works with NASA to monitor the ISS (see Protecting the “Pizza Box,” below).

Unfortunately, 95 percent of space trash is too small to track. Instruments on Earth can’t detect space debris smaller than 1 centimeter. NASA estimates that there are more than 100 million pieces this small. This tiny space junk includes everything from paint flakes to loose screws. Most of it broke off of bigger pieces of junk.

Large space trash hitting Earth is extremely rare. More often, it’s a problem for the satellites that connect phones and other communication systems. “The more objects there are in space, the more chance there is to interfere,” says Cowen.