Volunteer Nelson Rumsey, of Quincy, Il., collects plastic flowers from a house destroyed by the May 22 tornado in Joplin May 31, 2011. Missouri officials on Tuesday reduced the number of missing people from last week's devastating Joplin tornado to 10, a third of the previous day's count. The tornado that hit May 22 was rated an EF-5, or the strongest possible, and was rated the deadliest single twister in the United States since 1947. [Photo/Agencies]

The space shuttle Atlantis is shown as it is prepared to roll out from the Vehicle Assembly Building for the final flight of the space shuttle program at the Kennedy Space Center in Cape Canaveral, Florida May 31, 2011. Launch of Atlantis on Mission STS-135 is scheduled for July 8. [Photo/Agencies]