BRAzing of Aluminum Alloys IN Space

We propose to investigate the techniques of brazing (bonding by molten alloy) in microgravity and vacuum condition for space construction and repair of spacecrafts damaged by micrometeorites and orbital debris. A series of space (ISI) and terrestrial experiments, integrated with modeling and analysis are proposed to answer the practical and fundamental questions: (1) How can we take advantage of the absence of gravity and dominance of capillary forces in transporting the molten braze? (2) What composition of the brazing alloy and the brazing technique will enable strong and efficient bonding of structural elements and repair? Specifically: A comparison between flux and fluxless brazing techniques under space and terrestrial conditions will be performed. The phenomena to be studied under these conditions include molten metal kinetics, wetting and spreading of liquid clad/filler over topographically modified surfaces. The impact of residual oxygen and vacuum conditions outboard of the ISS will be analyzed. The applied aspects include direct verification if brazing of Al alloys is transferable to orbit for rapid repair of the pressure wall. For the first time, brazing in space will be processed using the patented fluxless Trillium technology. Further development includes design and testing of a space brazing furnace for brazing Al truss assemblies.