In the film Gravity, Russia uses a missile to take out a defunct satellite. The resulting cloud of debris begins to take out other satellites and threatens a space shuttle mission and the International Space Station (ISS). There was a great deal of debate when the film was released about its scientific accuracy. For example, the ISS and satellites do not orbit in the same region of space.

There is no debate, however, about the problem of space junk. There is also general agreement that the cascading destruction of Earth’s satellites by debris is possible. A 2013 study conducted for the Inter-Agency Space Debris Coordinating Committee found that collisions caused by debris were not only likely, but would rise sharply as human activity in space increases, according to the BBC.

The European Space Agency (ESA) estimates that there are currently 170 million bits of space debris larger than 1 mm. Some of those bits of junk are currently traveling at nearly 35,000 per hour. 

In hearings before congress this week, officials from NASA, the FAA and the U.S. military discussed the problem.

“Beside launch and reentry, orbital debris poses the biggest threat to spaceflight,” George Zamka, an official with the Federal Aviation Administration told Congress, according to NBC.

Congress is currently considering a proposal to give a single agency responsibility for monitoring space junk. Currently, the Department of Defense, the Federal Aviation Administration and Federal Communications Commission all track debris independently.

Late last year approval was given for the construction of a new U.S. “space fence.” However, that name is a bit misleading. The fence isn’t really a barrier, it is a high-frequency radar system designed to make it easier to track smaller pieces of debris. 

”There’s a lot of stuff up there, and the impact of the new space fence will be to track more objects and smaller objects. [Tracking the debris] is a necessity, but not sufficient. We need to move on to an active plan for removal,” Joan Johnson-Freese, a professor of national security affairs at the U.S. Naval War College told the Sydney Morning Herald.

So how do you stop bits of debris moving at 35 times the speed of a bullet? Several ideas have been suggested or are in the planning and development stages. Most of these involve pushing the debris down into Earth’s atmosphere to burn up. An overview of some of the suggestions is available at Space.com.

San Francisco based software engineer Alex Rasmussen has also created this interactive widget showing the location of satellites and space junk.