<div><p>Space shuttle Atlantis astronauts aboard the International Space Station delayed their second spacewalk Saturday after being jolted awake by a false alarm, NASA said.</p><p>Mission specialists Mike Foreman and Randy Bresnik had just two hours of sleep before a depressurization alarm sounded around 0253 GMT, forcing them to exit the Quest airlock, where astronauts "camp out" before spacewalks to purge nitrogen from their bloodstream to prevent decompression sickness.</p><p>Mission control in Houston, Texas confirmed the original alarm and subsequent alerts set off around the orbiting outpost were false.</p><p>The astronauts were allowed 30 extra minutes to snooze before their six-hour spacewalk, which will be 30 minutes shorter than planned.</p><p>Saturday's spacewalk, the second exterior work effort of the shuttle's 11-day mission, is intended to install a new system for storing spare parts on the space station's exterior.</p><img src="http://admatch-syndication.mochila.com/images/ad.gif?aid=63932611&bid=informcom" /></div><div id="copyright"><div>

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