A critical leak threatens the International Space Station's ability to regulate temperature

Space · Published 13 October 2026 Swipe more like this →

In short: When the International Space Station loses its coolant, the mission's stability is at risk. NASA astronauts are preparing for an intensive six-and-a-half-hour mission to investigate an ammonia leak that is currently depleting the station's vital cooling systems.

The International Space Station relies on complex cooling loops to manage heat, but a leak has been detected in the P6 (Port 6) truss. Specifically, the leak is located near or at a pump controller box that distributes coolant to various station systems. This leak is particularly concerning because it is depleting the coolant in a loop responsible for controlling one of the station's eight electrical power channels. This loss of coolant is particularly critical because the station's electrical power relies on eight distinct channels, one of which is currently being compromised by the depletion.

To address this, NASA astronauts Tom Marshburn and Chris Cassidy are tentatively scheduled to begin a spacewalk on Saturday, May 11. The mission is expected to start around 8:15 a.m. EDT and is projected to last approximately 6.5 hours. The primary objective of this extravehicular activity is to identify the exact source of the ammonia leak. The crew's recent work has also focused on power expansion, such as the May 1 installation of hardware for a seventh roll-out solar array. This addition is expected to boost the station's total power production by as much as 30%.

Maintaining thermal control is a constant challenge in orbit, where temperatures during spacewalks can reach 25 and 250 degrees. Beyond immediate repairs, NASA and international partners like JAXA and the CSA use these excursions to test advanced technologies. Recent research includes the SERFE experiment, which uses water evaporation to remove heat from suits, and the development of 'SpaceSkin'—a fabric with embedded sensors designed to detect micrometeoroid impacts. These innovations are essential for protecting astronauts and equipment as humanity prepares for extended missions to the Moon and Mars. Other ongoing studies include the MISSE-7 experiment, which examined how lunar dust and radiation degrade Apollo-era fibers. Additionally, the Canadian Space Agency is testing wireless dosimeters to better understand radiation exposure during these high-risk excursions.

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