The space shuttle Enterprise is towed by barge up the Hudson River in New York with the World Trade Center's Freedom Tower in the background while on it's way to the Intrepid Sea, Air and Space Museum where it will be permanently displayed, Wednesday, June 6, 2012. Photo Credit: (NASA/Bill Ingalls)

The space shuttle Enterprise is towed by barge up the Hudson River in New York with the World Trade Center's Freedom Tower in the background while on it's way to the Intrepid Sea, Air and Space Museum where it will be permanently displayed, Wednesday, June 6, 2012. Photo Credit: (NASA/Bill Ingalls)

Space shuttle Enterprise, mounted atop a NASA 747 Shuttle Carrier Aircraft (SCA), is seen as it flies over the Manhattan Skyline with Freedom Tower in the background, Friday, April 27, 2012, in New York. Enterprise was the first shuttle orbiter built for NASA performing test flights in the atmosphere and was incapable of spaceflight. Originally housed at the Smithsonian's Steven F. Udvar-Hazy Center, Enterprise will be demated from the SCA and placed on a barge that will eventually be moved by tugboat up the Hudson River to the Intrepid Sea, Air & Space Museum in June. Photo Credit: (NASA/Robert Markowitz)

The space shuttle Enterprise is towed by barge up the Hudson River with the New York skyline seen on the left and the Jersey City skyline on the right while on it's way to the Intrepid Sea, Air and Space Museum where it will be permanently displayed, Wednesday, June 6, 2012. Photo Credit: (NASA/Bill Ingalls)

CAPE CANAVERAL, Fla. – The Vehicle Assembly Building towers over two tugboats sitting alongside the Pegasus Barge which is moored in a secure area of the Turn Basin in the Launch Complex 39 area at NASA's Kennedy Space Center in Florida. The 266-foot-long and 50-foot-wide barge will be towed to Stennis by NASA's Freedom Star ship. Since being delivered to NASA in 1999, Pegasus sailed 41 times and transported 31 shuttle external fuel tanks from Michoud Assembly Facility near New Orleans to Kennedy. The barge will leave Kennedy, perhaps for the final time. Both the barge and shuttle equipment will remain in storage until their specific future uses are determined. The SSMEs themselves will be transported to Stennis separately for use with the agency’s new heavy-lift rocket, the Space Launch System. The work is part of the Space Shuttle Program’s transition and retirement processing. For more information about Shuttle Transition and Retirement, visit http://www.nasa.gov/mission_pages/transition/home/index.html. Photo credit: NASA/Cory Huston

CAPE CANAVERAL, Fla. – The Vehicle Assembly Building towers over two tugboats and the Pegasus Barge moored in a secure area of the Turn Basin in the Launch Complex 39 area at NASA's Kennedy Space Center in Florida. The 266-foot-long and 50-foot-wide barge will be towed by NASA's Freedom Star ship to deliver space shuttle main engine (SSME) ground support equipment to Stennis Space Center near Bay St. Louis, Miss. Since being delivered to NASA in 1999, Pegasus sailed 41 times and transported 31 shuttle external fuel tanks from Michoud Assembly Facility near New Orleans to Kennedy. The barge will leave Kennedy, perhaps for the final time. Both the barge and shuttle equipment will remain in storage until their specific future uses are determined. The SSMEs themselves will be transported to Stennis separately for use with the agency’s new heavy-lift rocket, the Space Launch System. The work is part of the Space Shuttle Program’s transition and retirement processing. For more information about Shuttle Transition and Retirement, visit http://www.nasa.gov/mission_pages/transition/home/index.html. Photo credit: NASA/ Kim Shiflett