In a week that seems to be at least partially dedicated to space movies, the International Space Station—and the six very real humans living within its confines—just had a Hollywood-worthy moment. The orbiting lab was threatened with a collision by space junk. It was saved by some quick-thinking people on Earth and by a little space ship that had docked to the station.
The threat began back in 2009, Smithsonian Magazine notes, when a piece of the deactivated Russian Cosmos-2251 satellite slammed into a U.S. Iridium satellite. Normally, that wouldn't matter. The debris from that collision—like the other pieces of the space junk that are stuck in orbit around Earth—is generally harmless to the ISS. As Gravity terrifyingly reminded us, though, that matter can also be incredibly destructive when it happens to be on a collision course with a human-carrying spacecraft. (Even something as tiny as a fleck of paint, the European Space Agency points out, can cause major damage—given that it travels at more than 100,000 miles an hour.) On Earth, space agencies have ground stations dedicated to tracking the space junk that whirls outside of Earth for potential collisions with the ISS.
And here's where things got scary. On October 27, a team of trackers detected a piece of Cosmos-2251—a piece, the ESA notes, about the size of a human hand—that was on a collision course with the ISS. (Calculations suggested that the object would pass, the agency puts it, "within 4km—too close for comfort.")
This, in itself, was extremely bad luck. But there was some further bad luck, too: There's a standard emergency maneuver designed for these situations, in place since 2012, that relies on Russia’s Progress supply ships. None of them, however, were in harbor during the time of the near-collision. Oof.
Fortunately there was a little bit of good luck, too—extremely good luck. The ISS currently has a craft docked to it: the Automated Transfer Vehicle Georges Lemaître, which ferries supplies to the station from Earth. The unmanned ship, despite its current status as an appendage of the ISS, is also controllable from Earth. Which meant that a team of engineers on the ground—a consortium of the five agencies that operate the Station together—were able to use the space ferry to help move the ISS out of harm's way.
Just six hours prior to the potential impact, at 17:42 GMT, the ATV Control Center team, based in Toulouse, France—but working with fellow engineers at control centers in Moscow and Houston—commanded a four-minute thruster burn. The force generated by that boost was enough to shift the course of the 463-ton Station by nearly a mile—and, as a result, to get it out of harm’s way. But it wasn't so far as to put the Station into a worse orbit—or, for that matter, to affect Progress, the craft that would dock with the Station a couple days after the emergency maneuver was enacted.
All's well up in space, in other words, because of some quick-thinking humans and an obliging little spacecraft. As the ESA puts it, "This is the first time the Station’s international partners have avoided space debris with such urgency."
This article was originally published at http://www.theatlantic.com/technology/archive/2014/11/a-little-ship-just-saved-the-international-space-station/382471/
