Additively manufactured components promise to revolutionize current manufacturing
processes. Metal parts require large and heavy machines to produce parts through
traditional subtractive means. However, through additive means even very complex
parts can be created with one or two relatively compact devices. This advantage has
brought additive processes to the interest of NASA as a means of in-space
manufacture.

For in-space manufacture of large components, it will be necessary to make and
join smaller pieces since additive manufacturing systems have a limited size. For
instance, a 3D printer is limited by the size of its stage. Once these smaller pieces
are created, they must be joined together. Adhesives and mechanical fasteners can be
used in some cases, but a stronger joining method is needed for most applications.
Friction Stir Welding(FSW) is a prime candidate for in-space welding, because it
isn’t gravity dependent and is very safe.

If friction stir welded joints of additively manufactured materials could be shown
to have acceptable properties, then FSW would be a viable option for the manufactured of parts in space.