Expedition 75 has completed the final run of a lead-free soldering experiment aboard the International Space Station while also carrying out lunar landing simulations and preparing for an upcoming cargo mission.
NASA's September 18 station update says flight engineer Anil Menon performed the last run of the MIYOKA investigation, which is testing whether crews can safely manufacture and repair electronics in microgravity using lead-free solder. The work follows several days of setup, soldering and documentation aboard the station.
MIYOKA is about repair capability away from Earth
The practical problem behind the experiment is simple: crews travelling farther from Earth cannot rely on quick replacement shipments every time an electronic component fails. NASA says MIYOKA uses circuit-board samples soldered in orbit that can later be returned and compared with equivalent work performed on the ground.
Earlier station updates this week showed Menon setting up containment and safety equipment, connecting the experiment hardware and photographing soldered samples for analysis. NASA has not announced the scientific result yet, so completing the final run should not be read as proof that lead-free soldering in microgravity has already been validated for operational use.
The experiment is instead one step toward understanding how solder behaves in weightlessness and what procedures astronauts would need if electronic repair became part of normal deep-space maintenance. NASA has linked the work to future missions where crews could be farther from resupply and ground support.
The station week also included lunar simulations
Soldering was only one part of Friday's schedule. NASA says crew members also took part in lunar landing simulation work, continued exercise research and prepared for an approaching cargo mission. Those activities sit alongside the station's regular maintenance and housekeeping workload.
The lunar simulation work is part of a broader effort to use the ISS as a test bed for procedures and human-performance questions that can inform missions beyond low Earth orbit. The station cannot reproduce lunar gravity, but it can give crews and researchers a controlled environment for testing workflows, interfaces and decision-making under operational constraints.
Cargo preparations are more immediate. Visiting spacecraft deliver experiments, food, hardware and other supplies, and station crews spend significant time configuring the orbital laboratory to receive and unload them. NASA's September 18 update describes those preparations as ongoing rather than announcing a launch or arrival milestone by itself.
The important research milestone this week is therefore the completion of MIYOKA's in-orbit run, not a final verdict on the technology. The samples and recorded data still need analysis. If the technique proves useful, it could contribute to a larger toolkit for crews who need to diagnose and repair electronics without waiting for a replacement part from Earth.
For now, Expedition 75 has finished the hands-on phase of this particular soldering test while the station continues doing what it does best: combining practical operations with small experiments aimed at making future missions more self-sufficient.
NASA's earlier updates this week make the timeline useful: Monday focused on setup, later sessions produced and photographed soldered samples, and Friday closed the in-orbit run. That progression shows why the September 18 milestone matters without pretending the analysis phase is already finished.
Reporting notes