International Space Station: Tiny Bits of Space Junk Could Threaten ISS—This is How it is Being Protected

Earth is surrounded by a cloud of junk. NASA's Goddard Space Flight Center/JSC

Early next week, the International Space Station will receive a new, smart shield to help it withstand one of space's most dangerous—if perhaps not its most romantic—threats: space junk. There's no garbage pick-up in space, but even tiny pieces of broken satellites and dead rockets can damage working satellites or the International Space Station.

That's why next Tuesday's SpaceX cargo launch to the space station will include a project called the Space Debris Sensor. (The poor device was originally called the Debris Resistive/Acoustic Grid Orbital Navy-NASA Sensor, or DRAGONS, but had to change its name after the team realized it would be traveling aboard the SpaceX Dragon capsule.) More than 23,000 pieces of space junk are so large that the U.S. Department of Defense can monitor them from Earth, but that's nothing next to the number of teeny tiny fragments—the sensor will focus on debris that's less than a millimeter across, smaller than a grain of sand.

That sounds innocent, but the steady hail of tiny debris wears away at the space station and other satellites. Scientists used to be able to study them by poring over damage to the space shuttles, but those haven't flown since 2011.

The Space Debris Sensor both shields the space station and takes detailed measurements of everything that hits it—size, speed, direction, time and energy. The sensor works by letting the debris punch through two layers to gather the information scientists want, then stopping the junk with a third layer.

At the device's outer layer is a grid of thin electrical wires that break when hit, leaving a dark spot like a single city block that has lost power at night. A second layer, six inches back, forms a sandwich of sorts: Because the sensor records what time and where the debris hits each later, scientists can piece those two points together to calculate how fast it's going and in what direction. The final layer stops the debris for good, which also lets the scientists figure out how heavy the debris was, potentially identifying the material it was made of.

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The design, which took more than a decade of development to perfect, ensures that all of that information can then be used to design spacecraft that can withstand the hail of debris they will inevitably be exposed to. And in the long term, the scientists behind the sensor would like to send a similar device even higher above Earth than the space station, where there's even more debris putting missions at risk.