T

This December 21, 2013 still image taken from NASA television, shows two US astronauts (lower R) who stepped outside the International Space Station to fix a broken equipment cooling system. Astronauts Rick Mastracchio and colleague Mike Hopkins are on the first of three urgent spacewalks called for due to a faulty valve that caused a partial shutdown in the system that regulates equipment temperature at the space station. == RESTRICTED TO EDITORIAL USE / MANDATORY CREDIT: “AFP PHOTO / NASA” – NO MARKETING / NO ADVERTISING CAMPAIGNS / DISTRIBUTED AS A SERVICE TO CLIENTS ==