Now I Get It: Houston, we have a space junk problem

Space agencies around the world have been launching objects for decades, and a lot of them haven’t come back down.

According to NASA, orbital debris, or “space junk,” is any object that’s no longer useful circling the earth.

It can include spent rocket stages, retired satellites or fragments of debris from previous space missions.

The U.S. Space Surveillance Network tracks about 21,000 orbiting pieces of debris larger than a softball. It’s also estimated there are millions of pieces of debris so small that they can’t be tracked. But they do have the potential to cause a lot of damage when traveling at speeds of up to 17,500 miles per hour.

In an interview with NASA’s Office of Safety and Mission Assurance, Nick Johnson, former NASA chief scientist studying orbital debris, said, “It turns out that particles as small as 5 millimeters can be catastrophic to a spacecraft if it’s in the wrong location. Even the International Space Station, which is the most heavily designed vehicle ever flown, is susceptible to anything larger than about half an inch.”

In fact, the ISS occasionally has to move out of the way to accommodate threatening debris.

Johnson added, “If we continue to operate as we have done — launching typically 70, 80 new missions every single year around the world — then the rate of collision is going to increase to a degree greater than we currently have.”

Space junk is a problem that is shared by numerous countries.

Back in 1996, a French satellite was damaged after it was hit from debris from a French rocket that had exploded a decade earlier.

In 2009, a defunct Russian satellite collided with and destroyed a functioning U.S. Iridium orbiter, creating more than 2,000 pieces of space junk.

In an episode of the Smithsonian National Air and Space Museum’s “What’s New in Aerospace?” Lisa Ruth Rand, a research associate at the museum, said, “Sometimes we generate debris when we’re trying to clean up debris but fail. So, in 2007, China attempted to bring down one of its own defunct weather satellites, and in doing so created one of the largest plumes of debris ever created in orbit.”

Controlling the space junk problem isn’t easy, but there are efforts to curtail it. NASA, the European Space Agency, Russia, China, Japan and France have developed guidelines to reduce the generation of new debris. In addition, the United Nations’ Committee on the Peaceful Uses of Outer Space created its own set of guidelines in 2007.

According to Johnson, “Unfortunately, even [with] some of the best [technological] minds currently around the world, we still have not yet identified a single [technologically affordable] concept” to fix the problem.