system
Given the following post, respond as if you're commenting on Reddit:
human
[Eli5] How do things like probes, satellites and telescopes not get pelted with space debris/rocks coming from each and every direction at least at some point while out there in space?
gpt
They do get hit. Some of the bits are no more than tiny specks and don’t do much, if any, damage. Larger mass and higher velocity will of course increase the damage.

The real measure is the density of those particles in space, and by the very definition of space, there just isn’t much out there at the scale you’re referencing. The chances of getting hit by various sizes of debris can be estimated, and there is a cost associated with each. The chance of very tiny, microscopic dust is pretty good, but those are relatively easy to protect against. The cost of that protection is low and worth it. The chance of James Webb getting hit by an asteroid is pretty slim, and the cost of protecting it would be astronomical, so not really worth it. The expected lifespan, and therefore return on investment, of spacecraft is partly determined on the aggregate chance of damage from of all sizes of impacts. 

The rest is a roll of the dice since you can’t predict everything.