<p><strong><a id="internal-source-marker_0.09470465362670077" href="http://www.nasa.gov/">NASA</a>'s <a href="http://www.nasa.gov/centers/kennedy/shuttleoperations/orbiters/orbitersend.html">space shuttle <em>Endeavour</em></a>, which concluded its final mission Wednesday, pierces a thick layer of clouds above <a href="http://travel.nationalgeographic.com/travel/united-states/florida-guide/">Florida</a> as it heads for the <a href="http://science.nationalgeographic.com/science/space/space-exploration/international-space-station-article.html">International Space Station</a> on May 16. </strong></p><p>The launch was the last for the <em>Endeavour</em>, which had been in service since 1992. (See <a href="http://news.nationalgeographic.com/news/2011/05/pictures/110516-nasa-space-shuttle-launch-endeavour-final-science-mark-kelly/">"Space Shuttle Pictures: 12 Endeavour Images to Remember."</a>) On its 25th mission <em>Endeavour</em> ferried a six-member crew commanded by astronaut Mark Kelly. Its payload included a <a href="http://news.nationalgeographic.com/news/2011/04/110429-shuttle-launch-endeavour-ams-space-science-nation/">U.S. $1.5-billion cosmic ray detector called the Alpha Magnetic Spectrometer to the space station</a>.</p><p>Kelly landed the space shuttle at Florida's Kennedy Space Center at 2:34 ET Wednesday, the final touchdown in the <em>Endeavour</em>'s 19-year history.</p><p>"It's sad to see her land for the last time," Kelly told NASA mission control, "but she really has a great legacy."</p><p><em>—Ker Than</em></p>