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How a Toothbrush Helped Save the Space Station

By Kim Smiley

Using ingenuity reminiscent of Apollo 13, the crew on the International Space Station (ISS) recently found a way to fix an ailing electrical system using handmade tools made with an allen wrench, a wire brush, a bolt and a toothbrush.

The events that led to this dramatic repair attempt can be built into a Cause Map, a visual root cause analysis to help illustrate the causes that contributed to the problem. In this example, the problem was an issue with the electrical system on the space station.  Electrical issues can obviously quickly become dangerous on a space station because the life support systems need electricity to function. The impacts to the schedule and potential issues with accomplishing all the mission goals are also worth considering.

In order to fix the problem, astronauts needed to replace a failed Main Bus Switching Unit, a component that is responsible for collecting and distributing power from the solar arrays.  The ISS has four Main Bus Switching Units and each serves two of the eight solar arrays so the loss of a one of the units significantly impacts power supply.

The units are located outside of the space station and the plan was to replace the malfunctioning unit during a spacewalk, but the two astronauts doing the work ran into a problem.  An accumulation of metal shavings caused a bolt to stick, preventing installation of the new unit.  The astronauts needed to find a way to remove the metal shavings, but none of the tools they had taken on the spacewalk could get the job done.

The nearest hardware store was over 200 miles of atmosphere away and the options were limited, but the crew found an elegantly simple solution to the problem.  They created a cleaning tool out of items onboard the space station, including a $3 toothbrush.  An extra space walk was planned, the metal shavings were cleared and the new Main Bus Switching Unit was successful installed.  A cheap toothbrush taped to a metal handle had helped fix a $100 billion space station.

And if you’re wondering which Astronaut drew the short end of the oral hygiene stick, don’t worry the tooth brush was a spare.

To view a high level Cause Map of this issue, click on “Download PDF” above.