A Falcon 9 rocket is launched by Space Exploration Technologies on its fourth cargo resupply service mission to the International Space Station, from Cape Canaveral Air Force Station in Florida September 21, 2014. The unmanned Falcon 9 rocket blasted off with more than 5,000 pounds (2,268 kg) of equipment, supplies and science experiments, including 20 live mice for medical experiments, a prototype 3-D printer and an instrument to monitor ocean wind speeds. (Photo by Michael Brown/Reuters)
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