[ISS] Contingency Spacewalk Underway Outside Space Station

From the discovery of a major leak in the International Space Station's coolant systems just 48 hours ago, two Astronauts - Chris Cassidy and Tom Marshburn are currently outside the Station doing a 6.5 hour Spacewalk, the 168th in Space Station history, to try find and repair the leak in the system.

The coolant system uses ammonia which is fed through cold plates and transfers heat away from many electronic components used to power the Station's systems.