The space debris around Earth is bad due to several reasons. One is a legacy of disinterest for the problem fueled by a greater concern for the fundamental diff

The space debris around Earth is bad due to several reasons. One is a legacy of disinterest for the problem fueled by a greater concern for the fundamental difficulties of space travel. Consider a stereotypical pseudo case study for a space mission in the '60s or '70s or thereabouts. First you have the launch, each stage is festooned with pyrotechnic actuators, cords, blankets, yo-yo despin bits and bobs, and so forth. Every launch deposits a shower of debris into orbit, which orbit depending on the orbit of the payload, some of them potentially long lived. Bolt heads, wires, paint flecks, etc. The final stage boosts the payload into its orbit then separates. Of necessity the final stage tends to be in a very similar orbit to the final payload, except weighing much more. For example, most sightings of the Sputnik spacecraft were actually sightings of the much brighter upper stage tagging along in orbit behind it. Ah but the stage is not necessarily done doing stuff yet, just not stuff it was intentionally designed to do. The stage will often have leftover propellant in it, and it was common to simply abandon the stage in place (on orbit) after its work was done. As a consequences, a lot of upper stages blew up on orbit after delivering payloads, creating yet another shower of debris into Earth orbit. And finally you have the payload itself, which was very commonly simply abandoned in place once it became derelict. Multiply all of that by the low operational lifespan of early satellites coupled with a high replacement cadence and you have a reason why Earth orbit got crudded up with debris in a short window of time. Today we are considerably more sensible about the problems of space debris so our launches are much cleaner. Instead of every launch creating a new mess in orbit every launch generally just inserts 1 or 2 pieces of large, easily trackable components (the payload and the upper stage, if it wasn't deorbited). For LEO launches the upper stage is typically deorbited immediately, for GTO launches the upper stage typically takes a handful of years to orbitally decay and re-enter. For this reason orbital debris has typically been on a flat or decreasing track over time during any given year. However, there are a few notable events in the past which have generated exceptional amounts of debris. One example is Project West Ford, which put thousands of tiny needles into orbit, which should have re-entered promptly except that some of the needles clumped up, leading them to have long-term stable orbits (which will last hundreds of years most likely), polluting some significant chunks of Earth orbit. Then you have the Iridium/Kosmos-2251 collision and the Chinese ASAT test, both of which injected huge quantities of debris into orbit. In general, all of these things can be cleaned up given application of modest resources, and the fact that we are no longer polluting Earth orbit with debris as rapidly as we once were means that we should be able to sustain far higher levels of space activity with far lower risks due to orbital debris than today.