Soldering in a Reduced Gravity Environment (SoRGE)

Future long-duration human exploration missions will be challenged by constraints on mass and volume allocations available for spare parts. Addressing this challenge will be critical to the success of these missions. As a result, it is necessary to consider new approaches to spacecraft maintenance and repair that reduce the need for large replacement components. Currently, crew members on the International Space Station (ISS) recover from faults by removing and replacing, using backup systems, or living without the function of Orbital Replacement Units (ORUs). These ORUs are returned to a depot where the root cause of the failure is determined and the ORU is repaired. The crew has some limited repair capability with the Modulation/DeModulation (MDM) ORU, where circuit cards are removed and replace in faulty units. The next step to reducing the size of the items being replaced would be to implement component-level repair. This mode of repair has been implemented by the U.S. Navy in an operational environment and is now part of their standard approach for maintenance. It is appropriate to consider whether this approach can be adapted for future spaceflight operations. To this end, the Soldering in a Reduced Gravity Environment (SoRGE) experiment studied the effect of gravity on the formation of solder joints on electronic circuit boards. This document describes the SoRGE experiment, the analysis methods, and results to date. This document will also contain comments from the crew regarding their experience conducting the SoRGE experiment as well as recommendations for future improvements. Finally, this document will discuss the plans for the SoRGE samples which remain on ISS.