Carrying water to the space station is a real challenge and cost, hence recycling water is critical. Waste water, sweat and other ISS water is constantly recycled in a complex system that evaporates and condenses clean water for reuse. For more information on the space station recycling system see the following link: Water Recovery System.
Figure 1 illustrates that system, a complex of tanks, piping, and at the core, a still, where water is heated and then condensed. To save on weight much of the system is made from aluminum and titanium… this is where S-Bond active solders are used. Figures 2 – 3 show the bonded assembly with aluminum bonding of a titanium tube. Soldering the titanium tube to the aluminum core was the required to assure excellent thermal contact for cooling the distillate on the tanks that fit into the aluminum core. S-Bond Technologies (SBT) has been supporting the water recovery system since early in the ISS program, NASA regularly orders components to replace the water recovery system. The active solders are used to, without flux and plating, bond the aluminum base to the titanium tubes.
Figure 2. Titanium cooling tube S-Bond solder bonded to an aluminum core used in condensing section of the ISS Water Recovery System.