[E.O.M.S.]

One of the biggest modern threats to spaceflight -- apart from politics  -- is space junk. For each satellite, rocket, capsule, space station,  missile, booster, observatory, dog or monkey we put into space, we  litter Earth orbit with 5 percent more junk every year.
So it seems we are doomed to failure. There's currently an estimated  5,500 tons of debris up there, and it's getting worse. The more active  we become in space, the more junk we shed, and it is a hyper-velocity  hazard, putting future astronauts and our multi-billion dollar satellite  industry at risk. What's more, space debris can interrupt satellite communications,  possibly even satellite TV signals -- we can't be having that!
SATELLITES:  Keep track of all the news from satellites orbiting not only Earth, but  other planetary bodies too.
Fortunately, various agencies around the world have accurate means of  tracking the larger bits of debris, providing some kind of warning  should a speeding bit of shrapnel get too close to our orbital real  estate. We might not be able to do anything (yet) about the smaller  stuff, but UK scientists have come up with a novel idea about how to  remove the larger stuff from orbit.
Enter the CubeSail, a modified solar sail designed to bring  dead satellites and rockets down to Earth.
HOWSTUFFWORKS:  Space junk is a growing issue, but what are the risks to astronauts?



Life's a Drag for Satellites.
The nanosatellite concept, designed by scientists  at the University of Surrey and funded by the European space  company Astrium, will be launched for space trials in 2011. Inspired by  the solar sail -- a spacecraft  propulsion system that uses the pressure of sunlight to get around space  -- the CubeSail uses air resistance to slow down its motion.
Unfolding into a 5×5 meter sheet of plastic, the CubeSail is designed  to "drag" defunct satellites from orbit, making use of the thin wisps  of atmospheric gases at orbital altitudes. Although the density of air  molecules is low, it's enough to make the sail act like a parachute,  slowing it down, dragging the dead satellite to a fiery reentry much  sooner than it would have done otherwise.
"Protecting our planet and environment is key for sustainable  growth," said Vaios Lappas, lead researcher on the project. "CubeSail is  a novel, low cost space mission which will demonstrate for the first  time space debris/satellite deorbiting using an ultra light 5 x 5 sail  stowed and supported on a 3 kg nanosatellite."
Seek and Destroy CubeSails?
Although this system is intended to be attached to future missions  that require a safe (and cheap) means of being removed from orbit, I can  imagine this kind of system being attached to some kind of "seek and  destroy" robot, taking out old orbital debris.
The CubeSail could be launched alone and under its own power and  guided to orbital debris being tracked from the surface. Once the robot  "docks" with the debris, it opens its sail, pulling the junk from space. Like with many space technologies, I also wonder if such a sci-fi  concept could have a military application.
Both the USA and China have demonstrated that they  can "shoot down" satellites with ground-launched missiles, filling  low-Earth orbit with millions of pieces of smaller bits of debris,  ultimately making Earth orbit impassible (there's no military advantage  in filling space with junk after all). Perhaps anti-satellite weaponry  could be more passive, sending ground-controlled CubeSails into orbit,  seeking out, attaching to, and ultimately destroying enemy satellites  but without the mess?

Images: The space junk problem (NASA) and the the CubeSail  concept (ESA/Univ. of Surrey/Astrium).
Sources: University  of Surrey, Physorg.com,  BBC