Re: Upside...
If space was closed by junk then ICBMs wouldn't work.
One of the (many) problems faced by Anti-Ballistic-Missile (ABM) systems is that it is perfectly possible to mix a bunch of "junk" in with the ICBM warhead(s). This would presumably be high volume, low mass stuff -- e.g. aluminized balloons designed to have a radar cross-section/signature similar to a warhead. The technical term is "decoys". The warheads will, presumably, be decorated to look like something other than warheads -- a second stage tank fragment perhaps. Eventually, drag will separate the dense warheads from the low-mass decoys, but decoys would make effective mid-flight interception quite difficult if not impossible. I think ABM systems are more popular with politicians than those who design, build and test them.