It is well known that micro meteorites, space junk, and other small objects can put a dent (Or rip through) in a spacecraft quite effectively. How can I protect people, sensitive electronics, and other items from impacts from these items?
Whipple shields are used for this very thing. The basic idea is that when the object strikes the first layer, it breaks apart, and the resulting pieces have a low enough energy to be stopped by the other layer(s). They have the added benefit of being much lighter than, say, a single thick slab of aluminum or titanium.
This site has some good photos of ground-tested Whipple shields and their variations.