Tiny variations can sometimes have big results. Just ask the crew of the International Space Station (ISS). On 31 July, a spike in electric current shut down a 780-pound pump module responsible for feeding ammonia coolant into the station’s starboard cooling system.

The malfunction caused no risk to the flight crew as the port-side cooling system immediately began providing coolant for critical systems, such as life support. Following the spike, the crew worked overnight to install jumper cables from the ISS’s Destiny Lab to power other redundancy systems.

After an unsuccessful attempt to power down and restart the cooling system, NASA has decided to conduct a spacewalk on 6 August to replace the failed component for a spare. A second spacewalk, planned for Monday, will connect fluid and electricity to the repaired module.

NASA reports today that crew members are going about their normal work schedules but most planned activities this week have been canceled or deferred to prepare for the spacewalks.

And in case you were wondering which side is starboard when you’re in space (isn’t every side “starboard” in space?) you can refer to this handy graphic.

Image: NASA