Framed in the doors of the Kennedy Center's Vehicle Assembly Building, the crawler begins the long journey toward Launch Pad 37B with space shuttle Discovery in April 2005. This enormous cross between a tank and a cargo ship is the largest self-powered land vehicle in the world. NASA hide caption

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The Alpha Magnetic Spectrometer is loaded into the vehicle that would take it to the space shuttle launchpad on March 15. The $2 billion cosmic ray detector will be carried to the International Space Station on Endeavour's final flight. NASA hide caption

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Researchers say that humpback whales are able to swim in remarkably straight lines during their seasonal migrations. They don't yet know, though, how the whales do it. Kike Calvo/AP hide caption

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Current laws say that truckers are not supposed to work for more than a 14-hour stretch; only 11 of those hours can be driving hours. Advocates of electronic truck monitors say the technology could help reduce highway accidents. Maggie Starbard/NPR hide caption

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Space shuttle Atlantis lifts off from Kennedy Space Center on May 14, 2010, in Cape Canaveral, Fla. Matt Stroshane/Getty Images hide caption

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This concept illustration for the Kennedy Space Center Visitor Complex shows how a space shuttle might be displayed, if NASA decides to award one to the facility. PGAV Destinations/Kennedy Space Center hide caption

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Space shuttle Discovery ended its 39th and final mission to space Wednesday, touching down at Kennedy Space Center in Cape Canaveral, Fla., just before noon local time. John Raoux/AP hide caption

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Space shuttle Discovery lifts off at Kennedy Space Center in Cape Canaveral, Fla., on Thursday for the final time. The world's most traveled spaceship is heading toward the International Space Station with a crew of six on a journey that marks the beginning of the end of the shuttle era. Chris O'Meara/AP hide caption

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Discovery leaves the International Space Station on June 11, 2008. NASA hide caption

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