Emergency Spacewalk

LONDON. May 19.KAZINFORM Flight engineers on the International Space Station (ISS), including U.S. astronaut Chris Cassidy (pictured), completed a 5.5-hour spacewalk on May 11 to repair a leaky coolant pump, National Geographic Daily News reports.

photo: QAZINFORM

The pump provides ammonia coolant to systems on the ISS responsible for generating electricity for the station.

The leak was initially discovered on May 9 by Canadian astronaut Chris Hadfield , who reported seeing flakes coming off the ISS. (Related: "Serious Space Station Leak Provokes Weekend Spacewalk." )