Space trash

Rico's friend (and fellow space junkie) Kelley forwards this Yahoo article by Jessica Orwig:

Since humans launched Sputnik 1 in 1957, we have polluted the once-empty space around Earth to the point that it is now becoming dangerous, according to former NASA scientist Donald Kessler. "We're at what we call 'critical density', where there are enough large objects in space that they collide with one another and create small debris faster than it can be removed," Kessler recently said.
For nearly twenty years, Kessler led NASA's Orbital Debris Program Office, which keeps track of all the growing clutter around Earth. He predicts that, eventually, there will be so much space junk that leaving Earth to explore deep-space will become impossible. That includes sending satellites to distant stretches of the solar system, like Pluto, and manned-missions to Mars.
Something must be done, he says. So he's come out of retirement to help find a solution.
Right now there are more than half a million pieces of man-made space junk orbiting Earth. And over twenty thousand of those pieces are the size of a softball or larger.
This junk accumulates over time as defunct satellites are left in space and meteors, as well as other man-made space debris, slam into them, generating even more, smaller bits of junk. After these collisions, the junk doesn't simply fly off into space. Instead, it is trapped by Earth's gravity and wraps like a belt around Earth, cluttering up our path to space.
While the size of this debris is an important factor, the speed at which it zips through space is what makes it so dangerous. At a distance of over two hundred miles above Earth's surface, objects move at about eighteen thousand miles per hour.  For comparison, that's faster than a speeding bullet fired from an AK-47 assault rifle, which travels at only sixteen hundred miles per hour.
Needless to say, if your spacecraft were hit with a softball-size scrap of metal traveling at eighteen thousand miles an hour, it could do some critical damage.
For example, in 2009, a retired Russian satellite collided with an American commercial satellite; the results were catastrophic. The collision destroyed both satellites, adding over two thousand pieces of space junk to that already-growing pile.
Collisions like these, together with the growing number of satellites we place into orbit, have brought us to the "critical density" that Kessler is so worried about.
Elon Musk, CEO of Tesla and SpaceX, has hopes to send four thousand satellites into low-Earth orbit, where most of the space junk is located, to provide Internet service worldwide. But there's one small problem: if Musk gets his wish, those satellites would only add to the problem.
While launching more satellites to space isn't a great idea, it's not the main problem. Most of the stuff we send up doesn't come down, and it is those dead satellites that we need to focus on, Kessler said. "The only way to solve this problem is to bring back the larger objects," Kessler told The Huffington Post in 2013. "If you want to stop this collision cascading process, you have to bring back satellites, and we don't know how to do that yet."
If we can't figure out how to return large satellites to Earth, then Kessler says we'll just have to start picking all the pieces up one-by-one, all while traveling at eighteen thousand miles an hour. It won't be an easy task.

Rico says surely Musk can come up with a garbage-sweeper to clean up the sky...