Junk affects us all. There is not a person on earth who is not influenced by it. Even in the most remote villages on earth that have never seen the outside world, junk is always present. In every society that ever lived, the solution to junk is to pile it all up somewhere and try to forget about it.
Junk also has a very curious property that I think deserves more scrutiny: it seems to multiply of its own accord. Anyone with a desk knows what I'm talking about. If you leave your desk unattended for too long, there always is more junk when you get back than there was when you left. As I like to say, junk expands to fill the space given to it. Personally, I feel there is a chance that junk operates beyond the laws of physics and can violate the law of conservation of energy. Sometimes I wonder whether or not the entire universe is nothing more than the junk pile of some alien civilization, and that's where it came from and why it is expanding. However, that hypothesis goes well beyond the realm of wild speculation into the land of pure lunacy, so I won't discuss it further.
There is a certain type of junk which is unique to the 20th and 21st centuries, and it will only grow and become more of a problem in the future. This is the junk that lurks in space, mostly low earth orbit.
Humanity has been sending stuff up into space for a long time. Officially, the Sputnik satellite was the first manmade object to orbit the earth, but the German V2 rockets in the 40's certainly had the capability to leave the atmosphere. Since then, we've sent up probes, experimental modules, communications satellites, space stations, various craft flown by people, and probably some secret stuff we're not privy to.
All of this adds more and more debris to orbital areas. Spent rocket stages may or may not fall back into the atmosphere, dead satellites linger, and general debris such as nuts, bolts, human waste, and at least one glove have all been ejected. While most of this will eventually burn up upon reentry, a lot of it can stay up there for a long time.
This poses a problem to space launches, one which heretofore has not been an issue, but will become one as the volume of junk grows. That problem is collision. Being hit by a 10 gram titanium nut doesn't sound like a big deal, unless you're travelling at orbital speed or around 16,000 mph. At that velocity, even a very minor object could cause catastrophic damage to a space vehicle. If we reach the point where low earth orbit becomes a very active economic zone, with vessels zipping around all over the place, then eventually a collision must occur. We should start now on working to find ways to defeat debris.
The most obvious solution is to not hit an object in the first place. If space vehicles came equipped with very accurate radar, they could see objects ahead of time and adjust course to miss them. Probably this would be handled by computer for the fastest possible response time.
Another solution would be armor. Now, with current materials, any armor capable of defeating objects screaming in at orbital speed would be so heavy you couldn't realistically launch it. Perhaps very strong but very light materials, such as graphene, could be used. Another option would be to surround the spacecraft in a lightweight foam or aerogel that would capture small particles.
A third option would be to deploy some sort of system to destroy objects before they impacted. If you had an extremely sensitive radar combined with a powerful rapid fire laser, you could have a computer target and destroy objects well before the spacecraft encountered them.
The fourth option would be to project some sort of energy field in front of the ship to deflect incoming objects. Weight is a vitally short luxury on a spacecraft, and an energy shield would weigh nothing. However, at this point we don't know how to build such a device.
The firth option would be to simply remove the junk. You could do this by sending up a giant inflatable 'net' that would capture wayward bits of trash and dispose of them in the atmosphere. This would probably be the most expensive option in the short term, but by clearing a path so that other ships didn't need Junk Defeating Technologies (JDT), it would probably be the cheapest option long term.