The US military's space defense command, or NORAD, is tracking an orbiting object that analysts speculate might be designed to fix — or attack — other satellites.

Governments keep tabs (and so can you) on what's floating in low orbit, which is why NORAD initially labeled the object as space debris.

But in May, Russia's government told the United Nations that a launch made last Christmas Day had sent four satellites into orbit, instead of the trio that is typically set up in a single launch.

That could explain the provenance of the mystery object, which is moving toward other Russian assets in space before potentially revealing its function. "It could have a number of functions, some civilian and some military," space security expert Patricia Lewis told the Financial Times.

One of the possible military uses was the launch of "kinetic pellets which shoot out at another satellite," Lewis said. In wars of the future, it might be advantageous — though very publicly hostile — to take out a rival nation's eyes.

In 2012, anonymous sources told Reuters, US intelligence completed a report analyzing "the growing vulnerability of US satellites that provide secure military communications, warn about enemy missile launches, and provide precise targeting coordinates."

Killing satellites is something both the US and the Soviet Union tested in the 1980s but had let go until testing by China led to the US doing the same (and making the report).

In 2007, China destroyed one of its own, aging weather satellites with an anti-satellite device mounted on a ballistic missile. The result was a proliferation of space debris that, as depicted in a fictional scenario in last year's blockbuster "Gravity," poses a danger to other satellites.

The US followed suit the next year by destroying a spy satellite — one that was already out of commission — simply by ramming a missile into it; no explosive was used. At the time, the Pentagon specified that resulting debris would burn upon re-entering the Earth's atmosphere.

The difference here, of course, is that Russia's experiment could involve an asset with more longevity, rather than a missile used just once. If it is indeed a weapon, it could lend new urgency to the previously tentative race to weaponize not just air, land, and sea, but space as well.