<p class="c0"><strong>Flight engineers on the&nbsp;<a class="c22" href="http://www.nasa.gov/mission_pages/station/main/index.html">International Space Station</a> (ISS), including U.S. astronaut Chris Cassidy (pictured), completed a 5.5-hour spacewalk on May 11 to repair a leaky coolant pump.</strong></p><p class="c0"><strong></strong>The pump provides ammonia coolant to systems on the ISS responsible for generating electricity for the station.</p><p class="c0">The leak was initially discovered on May 9 by Canadian astronaut&nbsp;<a class="c22" href="http://newswatch.nationalgeographic.com/2013/05/16/pop-astronaut-hadlfield-adjusting-to-terra-firma/">Chris Hadfield</a>, who reported seeing flakes coming off the ISS. (Related:&nbsp;<a class="c22" href="http://newswatch.nationalgeographic.com/2013/05/10/serious-space-station-leak-provokes-weekend-spacewalk/">"Serious Space Station Leak Provokes Weekend Spacewalk."</a>)</p><p class="c0">—<em>Jane J. Lee </em></p>

Emergency Spacewalk

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.

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.")

Jane J. Lee

Photograph courtesy NASA

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