Space Shuttle composite damage

Used to point at the unsolved problem of repairing composite aerospace structures in the field.

I'd like you to think about: if you had an additive manufacturing idea and you were doing a startup, what would your strategy be? What industry would you go after? What material would you go after? Why did we not talk about aluminum? Because aluminum has an oxide and it's hard enough to weld. Try to take little particles of it and join them together is going to be extremely difficult. Titanium doesn't have a surface active oxide that's hard to get rid of, so titanium is nice. Stainless steel is not bad from that point of view. Why haven't we talked about copper alloys? You could do copper alloys or brasses, but what's the volume there? The volume is in steel. Or if you're going to aerospace, you're looking at aluminum or titanium. Or you might get out of metals and into composites. So you might talk about plastics additive manufacturing, which probably has a number of applications in the aerospace industry to make excellent composite structures. Or maybe you've got an even better idea, if you can figure out how to repair those composite structures, because that's one of the big Achilles heels for composites in aerospace. We can make them, but we sure don't know how to repair them very well, and they do get dinged up every now and then. Look at the Space Shuttle.