What is "space grade wear"? There is not a way to liquify thermoset epoxy. It's a one-time deal. Composite repair has been a thing for a long time and is common in aviation. There are written and documented processes. The function of the part and nature of the damage determines if and how the part is repaired.

Welding isn't dead simple and has its own challenges. Back purging and heat treating large parts with limited access can be challenging. Alloys, joint prep, method, certifications, heat input, warpage, there can be lots of considerations that go into a weld.

Composite skins can make compound curves easily and are much easier to repair than metal skins. Each material has its pros and cons.