International Space Station Image Courtesy of NASA
Although most of us aren’t working in conditions quite as critical as those encountered on the International Space Station (ISS), the majority of us are very concerned with the uptime of our systems. On Saturday a liquid cooling system on the International Space Station malfunctioned, forcing the crew to power down some of the station’s vital systems. The downtime situation aboard the ISS serves as an excellent reminder about the importance of designing in redundancies on critical systems, as well as the importance of having spare parts readily available.
The malfunction on the ISS was the result of a pump module failure in one of the station’s two large liquid cooling loops. The second, or backup, cooling system is keeping the ISS up and running; however the station still has some of its operations shut down as the backup alone cannot handle 100% of the operations. The crew plans to replace the pump module this week with one of two backup pump modules that is located on the station. Although the backup pump module must be retrieved via a spacewalk, at least it didn’t have to be sent up from Earth!
The space station’s liquid cooling systems remove waste heat from electronics using cold plates and heat exchangers. There are two separate cooling loops within each cooling system. The process side cooling loops inside of the space station use water as the coolant while the external cooling loops use liquid ammonia to prevent freezing.
In a Space.com article about the malfunction, Denise Chow writes, “…while the intricacy of all the space station’s parts can sometimes lead to technical problems, the interaction of these complex systems is also what has kept the station operating successfully for over a decade.” According to Boeing, it was the first malfunction of the cooling system.
Cooling systems used for many applications, including data center cooling, medical equipment cooling, or manufacturing process cooling, are often considered “mission critical” equipment. To address this, Lytron can design and manufacture cooling systems with redundancies as well as other features to help ensure uptime. For example, Lytron’s LCS50 liquid cooling system for data centers has redundant pumps, optional redundant modulating valves, and isolation valves for hot swapping of all major components. Lytron also offers spare parts for its cooling systems.
Sources:
http://www.space.com/businesstechnology/international-space-station-complexities-100802.html
http://www.nasa.gov/mission_pages/station/main/index.html
http://www.nytimes.com/2010/08/02/science/space/02shuttle.html
