
NASA and contractor personnel work to secure the tow bar onto the space shuttle Atlantis at the Kennedy Space Center Shuttle Landing Facility (SLF) shortly after Atlantis (STS-135) landed early Thursday morning, July 21, 2011, in Cape Canaveral, Fla. The runway is marked to show where the nose landing gear wheels stopped. Overall, Atlantis spent 307 days in space and traveled nearly 126 million miles during its 33 flights. Atlantis, the fourth orbiter built, launched on its first mission on Oct. 3, 1985. Photo Credit: (NASA/Bill Ingalls)

NASA astronaut Mike Massimino, left, and Sesame Street's Elmo speak at the STS-135 Tweetup, Thursday, July 7, 2011, at Kennedy Space Center in Cape Canaveral, Fla. Elmo asked the astronauts questions about living and working in space. About 150 NASA Twitter followers attended the event. The STS-135 mission will be NASA's last space shuttle launch. Photo Credit: (NASA/Paul E. Alers)

NASA Shuttle Launch Director Michael Leinbach monitors the launch countdown from Firing Room Four of the Launch Control Center (LCC) at NASA's Kennedy Space Center on Friday, July 8, 2011, in Cape Canaveral, Fla. The launch of Atlantis, STS-135, is the final flight of the shuttle program, a 12-day mission to the International Space Station. Photo Credit: (NASA/Bill Ingalls)

The space shuttle Atlantis is seen shortly after the rotating service structure (RSS) was rolled back at launch pad 39a, Thursday, July 7, 2011 at the NASA Kennedy Space Center in Cape Canaveral, Fla. Atlantis is set to liftoff Friday, July 8, on the final flight of the shuttle program, STS-135, a 12-day mission to the International Space Station. Photo Credit: (NASA/Bill Ingalls)

LEGOs are seen assembled by students as part of a “Build the Future” activity inside a tent that was set up on the launch viewing area at NASA's Kennedy Space Center in Cape Canaveral, Fla. on Wednesday, Nov. 3, 2010. NASA and The LEGO Group signed a Space Act Agreement to spark children's interest in science, technology, engineering and math (STEM). Photo Credit: (NASA/Bill Ingalls)

NASA Officials, LEGO Group management, students, teachers and parents create their vision of the future in space with LEGO bricks and elements as part of a “Build the Future” activity inside a tent that was set up on the launch viewing area at NASA's Kennedy Space Center in Cape Canaveral, Fla. on Monday, Nov. 1, 2010. NASA and The LEGO Group signed a Space Act Agreement to spark children's interest in science, technology, engineering and math (STEM). Photo Credit: (NASA/Bill Ingalls)

NASA Kennedy Space center Director Robert Cabana talks with members of the shuttle tile team which are wearing flowered shirts together at the Shuttle Landing Facility (SLF) runway at NASA Kennedy Space Center shortly after the space shuttle Atlantis (STS-135) landed, completing its 13-day mission to the International Space Station (ISS) and the final flight of the Space Shuttle Program, early Thursday morning, July 21, 2011, in Cape Canaveral, Fla. Overall, Atlantis spent 307 days in space and traveled nearly 126 million miles during its 33 flights. Atlantis, the fourth orbiter built, launched on its first mission on Oct. 3, 1985. Photo Credit: (NASA/Bill Ingalls)

Space shuttle Atlantis is seen on launch pad 39a moments after the STS-135 crew arrived for their launch, Friday, July 8, 2011, at the NASA Kennedy Space Center in Cape Canaveral, Fla. The launch of Atlantis, STS-135, is the final flight of the shuttle program, a 12-day mission to the International Space Station. Photo Credit: (NASA/Bill Ingalls)

NASA Officials, LEGO Group management, students, teachers and parents create their vision of the future in space with LEGO bricks and elements as part of a “Build the Future” activity inside a tent that was set up on the launch viewing area at NASA's Kennedy Space Center in Cape Canaveral, Fla. on Monday, Nov. 1, 2010. NASA and The LEGO Group signed a Space Act Agreement to spark children's interest in science, technology, engineering and math (STEM). Photo Credit: (NASA/Bill Ingalls)

The space shuttle Endeavour is seen on launch pad 39a after the rollback of the Rotating Service Structure (RSS), Thursday, April 28, 2011, at Kennedy Space Center in Cape Canaveral, Fla. During the 14-day mission, Endeavour and the STS-134 crew will deliver the Alpha Magnetic Spectrometer (AMS) and spare parts including two S-band communications antennas, a high-pressure gas tank and additional spare parts for Dextre. Launch is targeted for Friday, April 29 at 3:47 p.m. EDT. Photo credit: (NASA/Bill Ingalls)

Warren Hinson, a NASA Emergency Response Team (ERT) member, keeps an eye out while flying near the Vehicle Assembly Building (VAB) prior to the launch of space shuttle Atlantis, STS-135, Friday, July 8, 2011, at Kennedy Space Center in Cape Canaveral, Fla. The launch of Atlantis, is the final flight of the shuttle program, a 12-day mission to the International Space Station. Photo Credit: (NASA/Bill Ingalls)

A dragonfly is seen at the edge of the lagoon near pad 39a and the space shuttle Atlantis on Wednesday, July 6, 2011 at the NASA Kennedy Space Center in Cape Canaveral, Fla. Space shuttle Atlantis is set to liftoff Friday, July 8, on the final flight of the shuttle program, STS-135, a 12-day mission to the International Space Station. Photo Credit: (NASA/Bill Ingalls)

Crowds of people are seen watching the rollout of the space shuttle Atlantis in this image made atop of the Mobile Launcher Platform (MLP) that is carrying Atlantis from High Bay 3 in the Vehicle Assembly Building to Launch Pad 39a for its final flight, Tuesday evening, May 31, 2011, at Kennedy Space Center in Cape Canaveral, Fla. The 3.4-mile trek, known as "rollout," will take about seven hours to complete. Atlantis will carry the Raffaello multipurpose logistics module to deliver supplies, logistics and spare parts to the International Space Station. The launch of STS-135 is targeted for July 8. Photo Credit: (NASA/Bill Ingalls)

Space shuttle Atlantis rolls away from the Vehicle Assembly Building as it begins its trip to its new home at the Kennedy Space Center Visitor Complex, early Friday, Nov. 2, 2012, in Cape Canaveral, Fla. The spacecraft traveled 125,935,769 miles during 33 spaceflights, including 12 missions to the International Space Station. Its final flight, STS-135, closed out the Space Shuttle Program era with a landing on July 21, 2011. Photo Credit: (NASA/Bill Ingalls)

NASA's SpaceX Crew-7 crew traveled to SpaceX facilities at NASA's Kennedy Space Center in Florida to train for their mission to the International Space Station. Imagery provided by SpaceX.

The space shuttle Endeavour is seen on launch pad 39a after the rollback of the Rotating Service Structure (RSS), Thursday, April 28, 2011, at Kennedy Space Center in Cape Canaveral, Fla. During the 14-day mission, Endeavour and the STS-134 crew will deliver the Alpha Magnetic Spectrometer (AMS) and spare parts including two S-band communications antennas, a high-pressure gas tank and additional spare parts for Dextre. Launch is targeted for Friday, April 29 at 3:47 p.m. EDT. Photo credit: (NASA/Bill Ingalls)

STS-135 Commander Chris Ferguson, right, talks to the media as NASA Administrator Charles Bolden, left, STS-135 Mission Specialists Rex Walheim, second from left, Sandy Magnus, third from left, and Pilot Doug Hurley look on shortly after the crew touched down in space shuttle Atlantis at NASA's Kennedy Space Center Shuttle Landing Facility (SLF), completing its 13-day mission to the International Space Station (ISS) and the final flight of the Space Shuttle Program, early Thursday morning, July 21, 2011, in Cape Canaveral, Fla. Overall, Atlantis spent 307 days in space and traveled nearly 126 million miles during its 33 flights. Atlantis, the fourth orbiter built, launched on its first mission on Oct. 3, 1985. Photo Credit: (NASA/Bill Ingalls)

The space shuttle Endeavour is seen on launch pad 39a as a storm passes by prior to the rollback of the Rotating Service Structure (RSS), Thursday, April 28, 2011, at Kennedy Space Center in Cape Canaveral, Fla. During the 14-day mission, Endeavour and the STS-134 crew will deliver the Alpha Magnetic Spectrometer (AMS) and spare parts including two S-band communications antennas, a high-pressure gas tank and additional spare parts for Dextre. Launch is targeted for Friday, April 29 at 3:47 p.m. EDT. Photo credit: (NASA/Bill Ingalls)

The STS-134 crew arrives in T-38 jets on Tuesday, April 26, 2011 at the NASA Kennedy Space Center Shuttle Landing Facility (SLF) in Cape Canaveral, Fla. During the 14-day mission, the space shuttle Endeavour and its crew will deliver the Alpha Magnetic Spectrometer (AMS) and spare parts including two S-band communications antennas, a high-pressure gas tank and additional spare parts for Dextre. Launch is targeted for Friday, April 29 at 3:47 p.m. EDT. Photo credit: (NASA/Bill Ingalls)

NASA and contractor personnel work on the space shuttle Atlantis at the Kennedy Space Center Shuttle Landing Facility (SLF) shortly after Atlantis (STS-135) landed early Thursday morning, July 21, 2011, in Cape Canaveral, Fla. Overall, Atlantis spent 307 days in space and traveled nearly 126 million miles during its 33 flights. Atlantis, the fourth orbiter built, launched on its first mission on Oct. 3, 1985. Photo Credit: (NASA/Bill Ingalls)

NASA Administrator Charles Bolden speaks to visitors at the NASA Kennedy Space Center Banana Creek viewing site prior to going to the Launch Control Center (LCC) for the planned launch of the space shuttle Atlantis from pad 39A on Friday, July 8, 2011, in Cape Canaveral, Fla. The launch of Atlantis, STS-135, is the final flight of the shuttle program, a 12-day mission to the International Space Station. Photo Credit: (NASA/Bill Ingalls)

The space shuttle Atlantis is revealed as the rotating service structure (RSS) is rolled back at launch pad 39a on Thursday, July 7, 2011 at the NASA Kennedy Space Center in Cape Canaveral, Fla. Atlantis is set to liftoff Friday, July 8, on the final flight of the shuttle program, STS-135, a 12-day mission to the International Space Station. Photo Credit: (NASA/Bill Ingalls)

Space shuttle Atlantis is seen during its trip to its new home at the Kennedy Space Center Visitor Complex, early Friday, Nov. 2, 2012, in Cape Canaveral, Fla. The spacecraft traveled 125,935,769 miles during 33 spaceflights, including 12 missions to the International Space Station. Its final flight, STS-135, closed out the Space Shuttle Program era with a landing on July 21, 2011. Photo Credit: (NASA/Bill Ingalls)

The space shuttle Atlantis is revealed as the rotating service structure (RSS) is rolled back at launch pad 39a on Thursday, July 7, 2011 at the NASA Kennedy Space Center in Cape Canaveral, Fla. Atlantis is set to liftoff Friday, July 8, on the final flight of the shuttle program, STS-135, a 12-day mission to the International Space Station. Photo Credit: (NASA/Bill Ingalls)

Space shuttle Atlantis is seen during its trip to its new home at the Kennedy Space Center Visitor Complex, early Friday, Nov. 2, 2012, in Cape Canaveral, Fla. The spacecraft traveled 125,935,769 miles during 33 spaceflights, including 12 missions to the International Space Station. Its final flight, STS-135, closed out the Space Shuttle Program era with a landing on July 21, 2011. Photo Credit: (NASA/Bill Ingalls)

NASA management watch the launch of space shuttle Discovery (STS-133) from the firing room at Kennedy Space Center, Thursday, Feb. 24, 2011, in Cape Canaveral, Fla. Discovery, on its 39th and final flight, is carrying the Italian-built Permanent Multipurpose Module (PMM), Express Logistics Carrier 4 (ELC4) and Robonaut 2, the first humanoid robot in space to the International Space Station. Photo Credit: (NASA/Bill Ingalls)

NASA Administrator Charles Boldin speaks during an unveiling ceremony of two USPS stamps that commemorate and celebrate 50 years of US Spaceflight and the MESSENGER program during an event, Wednesday, May 4, 2011 at the NASA Kennedy Space Center in Cape Canaveral, Fla. One stamp commemorates NASA’s Project Mercury, America’s first manned spaceflight program, and NASA astronaut Alan Shepard’s historic flight on May 5, 1961, aboard spacecraft Freedom 7. The other stamp draws attention to NASA’s unmanned MESSENGER mission, a scientific investigation of the planet Mercury. On March 17, 2011, MESSENGER became the first spacecraft to enter into orbit around Mercury. Photo Credit: (NASA/Bill Ingalls)

United Space Alliance Senior Space Shuttle Technician Mitchell Bromwell, left, and Randy Meyers of United Space Alliance display an American flag that has been flown all over the world by the U.S. military from atop the Mobile Launch Platform (MLP) as the space shuttle Atlantis begins its journey from High Bay 3 in the Vehicle Assembly Building to Launch Pad 39a for its final flight, Tuesday evening, May 31, 2011, at Kennedy Space Center in Cape Canaveral, Fla. The 3.4-mile trek, known as "rollout," will take about seven hours to complete. Atlantis will carry the Raffaello multipurpose logistics module to deliver supplies, logistics and spare parts to the International Space Station. The launch of STS-135 is targeted for July 8. Photo Credit: (NASA/Bill Ingalls)

NASA Kennedy Space center Director Robert Cabana sings an STS-135 landing car placard at the Shuttle Landing Facility (SLF) runway at NASA Kennedy Space Center shortly after the space shuttle Atlantis (STS-135) landed, completing its 13-day mission to the International Space Station (ISS) and the final flight of the Space Shuttle Program, early Thursday morning, July 21, 2011, in Cape Canaveral, Fla. Overall, Atlantis spent 307 days in space and traveled nearly 126 million miles during its 33 flights. Atlantis, the fourth orbiter built, launched on its first mission on Oct. 3, 1985. Photo Credit: (NASA/Bill Ingalls)

An faint profile outline of the space shuttle Discovery and launch pad 39a are seen projected in the sky as powerful xenon lights illuminate launch pad 39a on Wednesday, Nov. 3, 2010 at the NASA Kennedy Space Center in Cape Canaveral, Fla. During space shuttle Discovery's final spaceflight, the STS-133 crew members will take important spare parts to the International Space Station along with the Express Logistics Carrier-4. Photo Credit: (NASA/Bill Ingalls)

Pilot of the first space shuttle mission, STS-1, Bob Crippen speaks at an event where NASA Administrator Charles Bolden announced where four space shuttle orbiters will be permanently displayed at the conclusion of the Space Shuttle Program, Tuesday, April 12, 2011, at Kennedy Space Center in Cape Canaveral, Fla. The four orbiters, Enterprise, which currently is on display at the Smithsonian's Steven F. Udvar-Hazy Center near Washington Dulles International Airport, will move to the Intrepid Sea, Air & Space Museum in New York, Discovery will move to Udvar-Hazy, Endeavour will be displayed at the California Science Center in Los Angeles and Atlantis, in background, will be displayed at the Kennedy Space Center Visitor’s Complex. Photo Credit: (NASA/Bill Ingalls)

The space shuttle Atlantis is revealed as the rotating service structure (RSS) is rolled back at launch pad 39a on Thursday, July 7, 2011 at the NASA Kennedy Space Center in Cape Canaveral, Fla. Atlantis is set to liftoff Friday, July 8, on the final flight of the shuttle program, STS-135, a 12-day mission to the International Space Station. Photo Credit: (NASA/Bill Ingalls)

The space shuttle Endeavour is seen on launch pad 39a as a storm passes by prior to the rollback of the Rotating Service Structure (RSS), Thursday, April 28, 2011, at Kennedy Space Center in Cape Canaveral, Fla. During the 14-day mission, Endeavour and the STS-134 crew will deliver the Alpha Magnetic Spectrometer (AMS) and spare parts including two S-band communications antennas, a high-pressure gas tank and additional spare parts for Dextre. Launch is targeted for Friday, April 29 at 3:47 p.m. EDT. Photo credit: (NASA/Bill Ingalls)

NASA Officials, LEGO Group management, students, teachers and parents create their vision of the future in space with LEGO bricks and elements as part of a “Build the Future” activity inside a tent that was set up on the launch viewing area at NASA's Kennedy Space Center in Cape Canaveral, Fla. on Monday, Nov. 1, 2010. NASA and The LEGO Group signed a Space Act Agreement to spark children's interest in science, technology, engineering and math (STEM). Photo Credit: (NASA/Bill Ingalls)

Space Shuttle Atlantis (STS-135) is seen atop a Mobile Launcher Platform (MLP) just prior to beginning its journey from High Bay 3 in the Vehicle Assembly Building to Launch Pad 39a for its final flight, Tuesday evening, May 31, 2011, at Kennedy Space Center in Cape Canaveral, Fla. The 3.4-mile trek, known as "rollout," will take about seven hours to complete. Atlantis will carry the Raffaello multipurpose logistics module to deliver supplies, logistics and spare parts to the International Space Station. The launch of STS-135 is targeted for July 8. Photo Credit: (NASA/Bill Ingalls)

The space shuttle Atlantis is seen shortly after the rotating service structure (RSS) was rolled back at launch pad 39a, Thursday, July 7, 2011 at the NASA Kennedy Space Center in Cape Canaveral, Fla. Atlantis is set to liftoff Friday, July 8, on the final flight of the shuttle program, STS-135, a 12-day mission to the International Space Station. Photo Credit: (NASA/Bill Ingalls)

NASA Administrator Charles Bolden, right, and NASA Kennedy Space center Director Robert Cabana pose for a photograph together at the Shuttle Landing Facility (SLF) runway at NASA Kennedy Space Center shortly after the space shuttle Atlantis (STS-135) landed, completing its 13-day mission to the International Space Station (ISS) and the final flight of the Space Shuttle Program, early Thursday morning, July 21, 2011, in Cape Canaveral, Fla. Overall, Atlantis spent 307 days in space and traveled nearly 126 million miles during its 33 flights. Atlantis, the fourth orbiter built, launched on its first mission on Oct. 3, 1985. Photo Credit: (NASA/Bill Ingalls)

NASA Kennedy Space Center Assistant Launch Director Pete Nickolenko monitors the countdown to the launch of the space shuttle Endeavour (STS-134) from Firing Room Four of the Launch Control Center (LCC), Monday May 16, 2011, at the Kennedy Space Center in Cape Canaveral, Fla. During the mission, Endeavour and the STS-134 crew will deliver the Alpha Magnetic Spectrometer (AMS) and spare parts including two S-band communications antennas, a high-pressure gas tank and additional spare parts for Dextre. Photo Credit: (NASA/Bill Ingalls)

A large group of Astronauts from the Shuttle and Apollo projects wave to crowds as the Space shuttle Atlantis makes its trip to its new home at the Kennedy Space Center Visitor Complex, early Friday, Nov. 2, 2012, in Cape Canaveral, Fla. The spacecraft traveled 125,935,769 miles during 33 spaceflights, including 12 missions to the International Space Station. Its final flight, STS-135, closed out the Space Shuttle Program era with a landing on July 21, 2011. Photo Credit: (NASA/Bill Ingalls)

NASA Administrator Charles Bolden speaks with NASA Social attendees during the move of space shuttle Atlantis, Friday, Nov. 2, 2012, at Kennedy Space Center in Cape Canaveral, Fla. The spacecraft traveled 125,935,769 miles during 33 spaceflights, including 12 missions to the International Space Station. Its final flight, STS-135, closed out the Space Shuttle Program era with a landing on July 21, 2011. Photo Credit: (NASA/Bill Ingalls)

The United Launch Alliance Atlas V rocket with NASA’s Mars Atmosphere and Volatile EvolutioN (MAVEN) spacecraft launches from the Cape Canaveral Air Force Station Space Launch Complex 41, Monday, Nov. 18, 2013, Cape Canaveral, Florida. NASA’s Mars-bound spacecraft, the Mars Atmosphere and Volatile EvolutioN, or MAVEN, is the first spacecraft devoted to exploring and understanding the Martian upper atmosphere. Photo Credit: (NASA/Bill Ingalls)

NASA Photographer Kim Shiflett, left, and Videographer Glenn Benson capture a group photo of the launch team in Firing Room Four of the NASA Kennedy Space Center Launch Control Center (LCC) shortly after the space shuttle Atlantis, STS-135, launched on Friday, July 8, 2011, in Cape Canaveral, Fla. The launch of Atlantis is the final flight of the shuttle program, a 12-day mission to the International Space Station. Photo Credit: (NASA/Bill Ingalls)

Workers at the NASA Kennedy Space Center listen as NASA Administrator Charles Bolden announces where four space shuttle orbiters will be permanently displayed at the conclusion of the Space Shuttle Program during an event held at one of the Orbiter Processing Facilities, Tuesday, April 12, 2011, at Kennedy Space Center in Cape Canaveral, Fla. The four orbiters, Enterprise, which currently is on display at the Smithsonian's Steven F. Udvar-Hazy Center near Washington Dulles International Airport, will move to the Intrepid Sea, Air & Space Museum in New York, Discovery will move to Udvar-Hazy, Endeavour will be displayed at the California Science Center in Los Angeles and Atlantis, in background, will be displayed at the Kennedy Space Center Visitor’s Complex. Photo Credit: (NASA/Bill Ingalls)

NASA astronaut Mike Massimino, far left, Sesame Street's Elmo and NASA astronaut Doug Wheelock, far right, speak at the STS-135 Tweetup, Thursday, July 7, 2011, at Kennedy Space Center in Cape Canaveral, Fla. Elmo asked the astronauts questions about living and working in space. About 150 NASA Twitter followers attended the event. The STS-135 mission will be NASA's last space shuttle launch. Photo Credit: (NASA/Paul E. Alers)

The runway of the Shuttle Landing Facility (SLF) is marked to show where the wheels stopped for the space shuttle Discovery (STS-133) shortly after it landed, Wednesday, March 9, 2011, at Kennedy Space Center in Cape Canaveral, Fla., completing its 39th and final flight. Since 1984, Discovery flew 39 missions, spent 365 days in space, orbited Earth 5,830 times and traveled 148,221,675 miles. Photo credit: (NASA/Bill Ingalls)

NASA Administrator Charles Boldin speaks during an unveiling ceremony of two USPS stamps that commemorate and celebrate 50 years of US Spaceflight and the MESSENGER program during an event, Wednesday, May 4, 2011 at the NASA Kennedy Space Center in Cape Canaveral, Fla. One stamp commemorates NASA’s Project Mercury, America’s first manned spaceflight program, and NASA astronaut Alan Shepard’s historic flight on May 5, 1961, aboard spacecraft Freedom 7. The other stamp draws attention to NASA’s unmanned MESSENGER mission, a scientific investigation of the planet Mercury. On March 17, 2011, MESSENGER became the first spacecraft to enter into orbit around Mercury. Photo Credit: (NASA/Bill Ingalls)

NASA Kennedy Space Center Director and former astronaut Bob Cabana introduces NASA Administrator Charles Bolden where Bolden announced where four space shuttle orbiters will be permanently displayed at the conclusion of the Space Shuttle Program during an event held at one of the Orbiter Processing Facilities, Tuesday, April 12, 2011, at Kennedy Space Center in Cape Canaveral, Fla. The four orbiters, Enterprise, which currently is on display at the Smithsonian's Steven F. Udvar-Hazy Center near Washington Dulles International Airport, will move to the Intrepid Sea, Air & Space Museum in New York, Discovery will move to Udvar-Hazy, Endeavour will be displayed at the California Science Center in Los Angeles and Atlantis, in background, will be displayed at the Kennedy Space Center Visitor’s Complex. Photo Credit: (NASA/Bill Ingalls)

NASA’s Space Launch System (SLS) rocket with the Orion spacecraft aboard is seen atop the mobile launcher at Launchpad 39B at NASA’s Kennedy Space Center in Florida. Artemis I mission is the first integrated test of the agency’s deep space exploration systems: the Space Launch System rocket, Orion spacecraft, and supporting ground systems. The mission is the first in a series of increasingly complex missions to the Moon. Launch of the uncrewed flight test is targeted for no earlier than Sept. 3 at 2:17 p.m. ET. With Artemis missions, NASA will land the first woman and first person of color on the Moon, using innovative technologies to explore more of the lunar surface than ever before.

NASA and contractor personnel work on the space shuttle Atlantis at the Kennedy Space Center Shuttle Landing Facility (SLF) shortly after Atlantis (STS-135) landed early Thursday morning, July 21, 2011, in Cape Canaveral, Fla. Overall, Atlantis spent 307 days in space and traveled nearly 126 million miles during its 33 flights. Atlantis, the fourth orbiter built, launched on its first mission on Oct. 3, 1985. Photo Credit: (NASA/Bill Ingalls)

NASA Officials, LEGO Group management, students, teachers and parents create their vision of the future in space with LEGO bricks and elements as part of a “Build the Future” activity inside a tent that was set up on the launch viewing area at NASA's Kennedy Space Center in Cape Canaveral, Fla. on Monday, Nov. 1, 2010. NASA and The LEGO Group signed a Space Act Agreement to spark children's interest in science, technology, engineering and math (STEM). Photo Credit: (NASA/Bill Ingalls)

NASA Administrator Charles Bolden looks at the space shuttle Atlantis atop of the Mobile Launch Platform (MLP) just prior to rollout of Atlantis (STS-135) from High Bay 3 in the Vehicle Assembly Building to Launch Pad 39a for its final flight, Tuesday evening, May 31, 2011, at Kennedy Space Center in Cape Canaveral, Fla. The 3.4-mile trek, known as "rollout," will take about seven hours to complete. Atlantis will carry the Raffaello multipurpose logistics module to deliver supplies, logistics and spare parts to the International Space Station. The launch of STS-135 is targeted for July 8. Photo Credit: (NASA/Bill Ingalls)

NASA officials view space shuttle Endeavour (STS-134) as it launches skyward through the windows of Firing Room 4, Monday, May 16, 2011, at Kennedy Space Center in Cape Canaveral, Fla. During the 16-day mission, Endeavour, with Commander Mark Kelly, Pilot Gregory H. Johnson, Mission Specialists Michael Fincke, Greg Chamitoff, Andrew Feustel and European Space Agency astronaut Robert Vittori will deliver the Alpha Magnetic Spectrometer (AMS) and spare parts including two S-band communications antennas, a high-pressure gas tank and additional spare parts for Dextre. Photo Credit: (NASA/Bill Ingalls)

NASA Administrator Charles Bolden, left, announces the agency’s selection of Boeing and SpaceX to transport U.S. crews to and from the International Space Station using the Boeing CST-100 and the SpaceX Crew Dragon spacecraft as Former astronaut Bob Cabana, director of NASA's Kennedy Space Center in Florida looks on at NASA’s Kennedy Space Center in Cape Canaveral, Fla. on Tuesday, Sept. 16, 2014. These Commercial Crew Transportation Capability (CCtCap) contracts are designed to complete the NASA certification for a human space transportation system capable of carrying people into orbit. Once certification is complete, NASA plans to use these systems to transport astronauts to the space station and return them safely to Earth. Photo Credit: (NASA/Bill Ingalls)

The space shuttle Atlantis is revealed as the rotating service structure (RSS) is rolled back at launch pad 39a on Thursday, July 7, 2011 at the NASA Kennedy Space Center in Cape Canaveral, Fla. Atlantis is set to liftoff Friday, July 8, on the final flight of the shuttle program, STS-135, a 12-day mission to the International Space Station. Photo Credit: (NASA/Bill Ingalls)

STS-134 crew members, Commander Mark Kelly, Mission Specialists Greg Chamitoff, Andrew Feustel, Pilot Greg H. Johnson, Mission Specialist Mike Fincke and European Space Agency astronaut Roberto Vittori wave following their arrival to Kennedy Space Center, Tuesday, April 26, 2011, in Cape Canaveral, Fla. The six astronauts for space shuttle Endeavour's STS-134 mission to the International Space Station arrived at Kennedy's Shuttle Landing Facility (SLF) in T-38 jets early Tuesday afternoon. Photo Credit: (NASA/Bill Ingalls)

NASA's SpaceX Crew-7 crew participates in training at SpaceX facilities at NASA's Kennedy Space Center in Florida. Satoshi Furukawa is photographed here. Imagery provided by SpaceX

Close up view of the side the space shuttle Atlantis at the Kennedy Space Center Shuttle Landing Facility (SLF) shortly after Atlantis (STS-135) landed early Thursday morning, July 21, 2011, in Cape Canaveral, Fla. Overall, Atlantis spent 307 days in space and traveled nearly 126 million miles during its 33 flights. Atlantis, the fourth orbiter built, launched on its first mission on Oct. 3, 1985. Photo Credit: (NASA/Bill Ingalls)

NASA Chief of the Astronaut Office Peggy Whitson, right, walks with STS-135 Commander Chris Ferguson as he prepares to board the astrovan at the NASA's Kennedy Space Center Shuttle Landing Facility (SLF) shortly after he and the rest of the STS-135 crew landed in space shuttle Atlantis, completing a 13-day mission to the International Space Station (ISS) and the final flight of the Space Shuttle Program, early Thursday morning, July 21, 2011, in Cape Canaveral, Fla. Overall, Atlantis spent 307 days in space and traveled nearly 126 million miles during its 33 flights. Atlantis, the fourth orbiter built, launched on its first mission on Oct. 3, 1985. Photo Credit: (NASA/Bill Ingalls)

NASA Administrator Charles Bolden and Deputy Administrator Lori Garver talk at the Kennedy Space Center Shuttle Landing Facility (SLF) shortly after the space shuttle Atlantis (STS-135) landed early Thursday morning, July 21, 2011, in Cape Canaveral, Fla. Overall, Atlantis spent 307 days in space and traveled nearly 126 million miles during its 33 flights. Atlantis, the fourth orbiter built, launched on its first mission on Oct. 3, 1985. Photo Credit: (NASA/Bill Ingalls)

201105150010hq (15 May 2011) --- The space shuttle Endeavour is seen on launch pad 39A after the rollback of the Rotating Service Structure (RSS), May 15, 2011, at Kennedy Space Center in Cape Canaveral, Fla. During the mission, Endeavour and the STS-134 crew will deliver the Alpha Magnetic Spectrometer (AMS) and spare parts including two S-band communications antennas, a high-pressure gas tank and additional spare parts for Dextre. Launch is targeted for May 16 at 8:56 a.m. (EDT). Photo credit: NASA/Bill Ingalls

President of LEGO Education USA Stephan Turnipseed, back left, and Associate Administrator for Education and Astronaut Leland Melvin, 2nd from right, talk with a student during the “Build the Future” activity where students created their vision of the future in space with LEGO bricks and elements inside a tent that was set up on the launch viewing area at NASA's Kennedy Space Center in Cape Canaveral, Fla. on Monday, Nov. 1, 2010. NASA and The LEGO Group signed a Space Act Agreement to spark children's interest in science, technology, engineering and math (STEM). Photo Credit: (NASA/Bill Ingalls)

Space Shuttle Atlantis (STS-135) is seen atop the Mobile Launch Platform (MLP) during its journey from High Bay 3 in the Vehicle Assembly Building to Launch Pad 39a for its final flight, Tuesday evening, May 31, 2011, at Kennedy Space Center in Cape Canaveral, Fla. The 3.4-mile trek, known as "rollout," will take about seven hours to complete. Atlantis will carry the Raffaello multipurpose logistics module to deliver supplies, logistics and spare parts to the International Space Station. The launch of STS-135 is targeted for July 8. Photo Credit: (NASA/Bill Ingalls)

NASA Officials, LEGO Group management, students, teachers and parents create their vision of the future in space with LEGO bricks and elements as part of a “Build the Future” activity inside a tent that was set up on the launch viewing area at NASA's Kennedy Space Center in Cape Canaveral, Fla. on Wednesday, Nov. 3, 2010. NASA and The LEGO Group signed a Space Act Agreement to spark children's interest in science, technology, engineering and math (STEM). Photo Credit: (NASA/Bill Ingalls)

Space shuttle Atlantis is seen during its trip to its new home at the Kennedy Space Center Visitor Complex, early Friday, Nov. 2, 2012, in Cape Canaveral, Fla. The spacecraft traveled 125,935,769 miles during 33 spaceflights, including 12 missions to the International Space Station. Its final flight, STS-135, closed out the Space Shuttle Program era with a landing on July 21, 2011. Photo Credit: (NASA/Bill Ingalls)

Former astronaut Bob Cabana, director of NASA's Kennedy Space Center in Florida, speaks during a news conference where it was announced that Boeing and SpaceX have been selected to transport U.S. crews to and from the International Space Station using the Boeing CST-100 and the SpaceX Crew Dragon spacecraft, at NASA’s Kennedy Space Center in Cape Canaveral, Fla. on Tuesday, Sept. 16, 2014. These Commercial Crew Transportation Capability (CCtCap) contracts are designed to complete the NASA certification for a human space transportation system capable of carrying people into orbit. Once certification is complete, NASA plans to use these systems to transport astronauts to the space station and return them safely to Earth. Photo Credit: (NASA/Bill Ingalls)

Kennedy Space Center Director Robert Cabana, left, and NASA Administrator Charles Bolden talk about space shuttle Atlantis, Friday, Nov. 2, 2012, in Cape Canaveral, Fla. The spacecraft traveled 125,935,769 miles during 33 spaceflights, including 12 missions to the International Space Station. Its final flight, STS-135, closed out the Space Shuttle Program era with a landing on July 21, 2011. Photo Credit: (NASA/Bill Ingalls)

Pilot of the first space shuttle mission, STS-1, Bob Crippen speaks at an event where NASA Administrator Charles Bolden announced where four space shuttle orbiters will be permanently displayed at the conclusion of the Space Shuttle Program, Tuesday, April 12, 2011, at Kennedy Space Center in Cape Canaveral, Fla. The four orbiters, Enterprise, which currently is on display at the Smithsonian's Steven F. Udvar-Hazy Center near Washington Dulles International Airport, will move to the Intrepid Sea, Air & Space Museum in New York, Discovery will move to Udvar-Hazy, Endeavour will be displayed at the California Science Center in Los Angeles and Atlantis, in background, will be displayed at the Kennedy Space Center Visitor’s Complex. Photo Credit: (NASA/Bill Ingalls)

The flame trench underneath the space shuttle Atlantis at pad 39a is seen on Thursday, July 7, 2011 at the NASA Kennedy Space Center in Cape Canaveral, Fla. Space shuttle Atlantis is set to liftoff Friday, July 8, on the final flight of the shuttle program, STS-135, a 12-day mission to the International Space Station. Photo Credit: (NASA/Bill Ingalls)

Space Shuttle Atlantis (STS-135) is seen atop the Mobile Launch Platform (MLP) during its journey from High Bay 3 in the Vehicle Assembly Building to Launch Pad 39a for its final flight, Tuesday evening, May 31, 2011, at Kennedy Space Center in Cape Canaveral, Fla. The 3.4-mile trek, known as "rollout," will take about seven hours to complete. Atlantis will carry the Raffaello multipurpose logistics module to deliver supplies, logistics and spare parts to the International Space Station. The launch of STS-135 is targeted for July 8. Photo Credit: (NASA/Bill Ingalls)

The space shuttle Discovery is seen shortly after the Rotating Service Structure was rolled back at launch pad 39A, at the Kennedy Space Center in Cape Canaveral, Florida, on Wednesday, Feb. 23, 2011. Discovery, on its 39th and final flight, will carry the Italian-built Permanent Multipurpose Module (PMM), Express Logistics Carrier 4 (ELC4) and Robonaut 2, the first humanoid robot in space to the International Space Station. Photo Credit: (NASA/Bill Ingalls)

NASA Administrator Charles Bolden listens to a reporter’s question after he announced the agency’s selection of Boeing and SpaceX to transport U.S. crews to and from the International Space Station using the Boeing CST-100 and the SpaceX Crew Dragon spacecraft, at NASA’s Kennedy Space Center in Cape Canaveral, Fla. on Tuesday, Sept. 16, 2014. These Commercial Crew Transportation Capability (CCtCap) contracts are designed to complete the NASA certification for a human space transportation system capable of carrying people into orbit. Once certification is complete, NASA plans to use these systems to transport astronauts to the space station and return them safely to Earth. Photo Credit: (NASA/Bill Ingalls)

Space shuttle Atlantis is seen as it launches from pad 39A on Friday, July 8, 2011, at NASA's Kennedy Space Center in Cape Canaveral, Fla. The launch of Atlantis, STS-135, is the final flight of the shuttle program, a 12-day mission to the International Space Station. Photo Credit: (NASA/Bill Ingalls)

NASA Administrator Charles Bolden and Deputy Administrator Lori Garver walk under the space shuttle Atlantis at the Kennedy Space Center Shuttle Landing Facility (SLF) shortly after Atlantis (STS-135) landed early Thursday morning, July 21, 2011, in Cape Canaveral, Fla. Overall, Atlantis spent 307 days in space and traveled nearly 126 million miles during its 33 flights. Atlantis, the fourth orbiter built, launched on its first mission on Oct. 3, 1985. Photo Credit: (NASA/Bill Ingalls)

NASA Administrator Charles Bolden congratulates the launch team in the NASA Kennedy Space Center Firing Room Four of the Launch Control Center (LCC) shortly after the space shuttle Atlantis, STS-135, launched on Friday, July 8, 2011, in Cape Canaveral, Fla. The launch of Atlantis is the final flight of the shuttle program, a 12-day mission to the International Space Station. Photo Credit: (NASA/Bill Ingalls)

NASA Administrator Charles Bolden announces where four space shuttle orbiters will be permanently displayed at the conclusion of the Space Shuttle Program during an event held at one of the Orbiter Processing Facilities, Tuesday, April 12, 2011, at Kennedy Space Center in Cape Canaveral, Fla. The four orbiters, Enterprise, which currently is on display at the Smithsonian's Steven F. Udvar-Hazy Center near Washington Dulles International Airport, will move to the Intrepid Sea, Air & Space Museum in New York, Discovery will move to Udvar-Hazy, Endeavour will be displayed at the California Science Center in Los Angeles and Atlantis, in background, will be displayed at the Kennedy Space Center Visitor’s Complex. Photo Credit: (NASA/Bill Ingalls)

The crew of STS-135 is seen as they depart the NASA Kennedy Space Center, Operations and Checkout Building and get into the Astrovan for launch pad 39A, on Friday, July 8, 2011 in Cape Canaveral, Fla. The launch of Atlantis, STS-135, is the final flight of the shuttle program, a 12-day mission to the International Space Station. Photo Credit: (NASA/Jerry Ross)

An empty High Bay 3 of the Vehicle Assembly Building is seen shortly after space shuttle Atlantis (STS-135) began its journey from the Vehicle Assembly Building to Launch Pad 39a for its final flight, Tuesday evening, May 31, 2011, at Kennedy Space Center in Cape Canaveral, Fla. The 3.4-mile trek, known as "rollout," will take about seven hours to complete. Atlantis will carry the Raffaello multipurpose logistics module to deliver supplies, logistics and spare parts to the International Space Station. The launch of STS-135 is targeted for July 8. Photo Credit: (NASA/Bill Ingalls)

The runway of the Shuttle Landing Facility (SLF) is marked to show where the main landing gear wheels stopped for the space shuttle Atlantis (STS-135) shortly after it landed early Thursday morning, July 21, 2011, in Cape Canaveral, Fla. Overall, Atlantis spent 307 days in space and traveled nearly 126 million miles during its 33 flights. Atlantis, the fourth orbiter built, launched on its first mission on Oct. 3, 1985. Photo Credit: (NASA/Bill Ingalls)

United States Postal Service Vice President of Finance Steve Masse, left, and NASA Mercury Astronaut Scott Carpenter, unveil two USPS stamps to commemorate and celebrate 50 years of US Spaceflight and the MESSENGER program during an event, Wednesday, May 4, 2011 at the NASA Kennedy Space Center in Cape Canaveral, Fla. One stamp commemorates NASA’s Project Mercury, America’s first manned spaceflight program, and NASA astronaut Alan Shepard’s historic flight on May 5, 1961, aboard spacecraft Freedom 7. The other stamp draws attention to NASA’s unmanned MESSENGER mission, a scientific investigation of the planet Mercury. On March 17, 2011, MESSENGER became the first spacecraft to enter into orbit around Mercury. Photo Credit: (NASA/Bill Ingalls)

Kennedy Space Center Director Robert Cabana takes a picture of space shuttle Atlantis, Friday, Nov. 2, 2012, in Cape Canaveral, Fla. The spacecraft traveled 125,935,769 miles during 33 spaceflights, including 12 missions to the International Space Station. Its final flight, STS-135, closed out the Space Shuttle Program era with a landing on July 21, 2011. Photo Credit: (NASA/Bill Ingalls)

The Astrovan carrying the STS-135 crew; Chris Furgeson, commander, Doug Hurley, pilot, and mission specialists Rex Walheim and Sandy Mangus, rolls toward launch pad 39a and space shuttle Atlantis, Friday, July 8, 2011, at Kennedy Space Center in Cape Canaveral, Fla. The launch of Atlantis, STS-135, is the final flight of the shuttle program, a 12-day mission to the International Space Station. Photo Credit: (NASA/Bill Ingalls)

NASA Administrator Charles Bolden, left, and Kennedy Space Center director Robert Cabana pose for a photo as space shuttle Atlantis rolls toward its new home at the Kennedy Space Center Visitor Complex, early Friday, Nov. 2, 2012, in Cape Canaveral, Fla. The spacecraft traveled 125,935,769 miles during 33 spaceflights, including 12 missions to the International Space Station. Its final flight, STS-135, closed out the Space Shuttle Program era with a landing on July 21, 2011. Photo Credit: (NASA/Bill Ingalls)

NASA Astronaut and STS-135 Commander Chris Ferguson walks underneath the space shuttle Atlantis shortly after he and the rest of the STS-135 crew landed at NASA's Kennedy Space Center Shuttle Landing Facility (SLF), completing a 13-day mission to the International Space Station (ISS) and the final flight of the Space Shuttle Program, early Thursday morning, July 21, 2011, in Cape Canaveral, Fla. Overall, Atlantis spent 307 days in space and traveled nearly 126 million miles during its 33 flights. Atlantis, the fourth orbiter built, launched on its first mission on Oct. 3, 1985. Photo Credit: (NASA/Bill Ingalls)

From left, Pilot of the first space shuttle mission, STS-1, Bob Crippen, NASA Administrator Charles Bolden, NASA Johnson Space Center Director of Flight Crew Operations, and Astronaut, Janet Kavandi, NASA Kennedy Space Center Director and former astronaut Bob Cabana, and Endeavour Vehicle Manager for United Space Alliance Mike Parrish pose for a photograph outside of the an Orbiter Processing Facility with the space shuttle Atlantis shortly after Bolden announced where four space shuttle orbiters will be permanently displayed at the conclusion of the Space Shuttle Program, Tuesday, April 12, 2011, at Kennedy Space Center in Cape Canaveral, Fla. The four orbiters, Enterprise, which currently is on display at the Smithsonian's Steven F. Udvar-Hazy Center near Washington Dulles International Airport, will move to the Intrepid Sea, Air & Space Museum in New York, Discovery will move to Udvar-Hazy, Endeavour will be displayed at the California Science Center in Los Angeles and Atlantis, in background, will be displayed at the Kennedy Space Center Visitor’s Complex. Photo Credit: (NASA/Bill Ingalls)

Daughters of NASA astronaut Alan Shepard, Laura Shepard Churchley, standing left, Alice Wackermann and Julie Jenkins, standing right, speak during an unveiling ceremony of two USPS stamps that commemorate and celebrate 50 years of US Spaceflight and the MESSENGER program during an event, Wednesday, May 4, 2011 at the NASA Kennedy Space Center in Cape Canaveral, Fla. One stamp commemorates NASA’s Project Mercury, America’s first manned spaceflight program, and NASA astronaut Alan Shepard’s historic flight on May 5, 1961, aboard spacecraft Freedom 7. The other stamp draws attention to NASA’s unmanned MESSENGER mission, a scientific investigation of the planet Mercury. On March 17, 2011, MESSENGER became the first spacecraft to enter into orbit around Mercury. Photo Credit: (NASA/Bill Ingalls)

The STS-135 astronauts, from left, Mission Specialists Rex Walheim, Sandy Magnus, Pilot Doug Hurley and Commander Chris Ferguson all pose for photographers shortly after they touched down in the space shuttle Atlantis at NASA's Kennedy Space Center Shuttle Landing Facility (SLF), completing its 13-day mission to the International Space Station (ISS) and the final flight of the Space Shuttle Program, early Thursday morning, July 21, 2011, in Cape Canaveral, Fla. Overall, Atlantis spent 307 days in space and traveled nearly 126 million miles during its 33 flights. Atlantis, the fourth orbiter built, launched on its first mission on Oct. 3, 1985. Photo Credit: (NASA/Bill Ingalls)

NASA Officials, LEGO Group management, students, teachers and parents create their vision of the future in space with LEGO bricks and elements as part of a “Build the Future” activity inside a tent that was set up on the launch viewing area at NASA's Kennedy Space Center in Cape Canaveral, Fla. on Monday, Nov. 1, 2010. NASA and The LEGO Group signed a Space Act Agreement to spark children's interest in science, technology, engineering and math (STEM). Photo Credit: (NASA/Bill Ingalls)

The space shuttle Atlantis is revealed as the rotating service structure (RSS) is rolled back at launch pad 39a on Thursday, July 7, 2011 at the NASA Kennedy Space Center in Cape Canaveral, Fla. Atlantis is set to liftoff Friday, July 8, on the final flight of the shuttle program, STS-135, a 12-day mission to the International Space Station. Photo Credit: (NASA/Bill Ingalls)

The STS-134 crew flies over the Shuttle Landing Facility (SLF) in T-38 jets on Tuesday, April 26, 2011 at NASA's Kennedy Space Center in Cape Canaveral, Fla., as they arrive for their upcoming mission. During the 14-day mission, the space shuttle Endeavour and its crew will deliver the Alpha Magnetic Spectrometer (AMS) and spare parts including two S-band communications antennas, a high-pressure gas tank and additional spare parts for Dextre. Launch is targeted for Friday, April 29 at 3:47 p.m. EDT. Photo credit: (NASA/Bill Ingalls)

The space shuttle Atlantis is revealed as the rotating service structure (RSS) is rolled back at launch pad 39a on Thursday, July 7, 2011 at the NASA Kennedy Space Center in Cape Canaveral, Fla. Atlantis is set to liftoff Friday, July 8, on the final flight of the shuttle program, STS-135, a 12-day mission to the International Space Station. Photo Credit: (NASA/Bill Ingalls)

Cheryl Hurst, Director of Education and External Relations at Kennedy Space Center, speaks at the signing ceremony for space shuttle Atlantis, background, Friday, Nov. 2, 2012, in Cape Canaveral, Fla. The spacecraft traveled 125,935,769 miles during 33 spaceflights, including 12 missions to the International Space Station. Its final flight, STS-135, closed out the Space Shuttle Program era with a landing on July 21, 2011. Photo Credit: (NASA/Bill Ingalls)

The Astrovan carrying the STS-135 crew; Chris Furgeson, commander, Doug Hurley, pilot, and mission specialists Rex Walheim and Sandy Mangus, rolls past the Vehicle Assembly Building (VAB) and Launch Control Center (LCC), on its way to launch pad 39a and space shuttle Atlantis, Friday, July 8, 2011, at Kennedy Space Center in Cape Canaveral, Fla. The launch of Atlantis, STS-135, is the final flight of the shuttle program, a 12-day mission to the International Space Station. Photo Credit: (NASA/Bill Ingalls)

NASA International Space Station Program Office Manager Michael Suffredini, left, NASA Administrator Charles Bolden, second from left, Deputy Administrator Lori Garver, Manager, Space Shuttle Program Office John Shannon, third from left, and an unidentified colleague, talk under the space shuttle Atlantis at the Kennedy Space Center Shuttle Landing Facility (SLF) shortly after Atlantis (STS-135) landed early Thursday morning, July 21, 2011, in Cape Canaveral, Fla. Overall, Atlantis spent 307 days in space and traveled nearly 126 million miles during its 33 flights. Atlantis, the fourth orbiter built, launched on its first mission on Oct. 3, 1985. Photo Credit: (NASA/Bill Ingalls)

NASA Administrator Charles Bolden, left, and NASA Kennedy Space center Director Robert Cabana walk along the Shuttle Landing Facility (SLF) runway at NASA Kennedy Space Center shortly after the space shuttle Atlantis (STS-135) landed, completing its 13-day mission to the International Space Station (ISS) and the final flight of the Space Shuttle Program, early Thursday morning, July 21, 2011, in Cape Canaveral, Fla. Overall, Atlantis spent 307 days in space and traveled nearly 126 million miles during its 33 flights. Atlantis, the fourth orbiter built, launched on its first mission on Oct. 3, 1985. Photo Credit: (NASA/Bill Ingalls)

NASA Administrator Charles Bolden speaks with NASA Social attendees during the move of space shuttle Atlantis, Friday, Nov. 2, 2012, at Kennedy Space Center in Cape Canaveral, Fla. The spacecraft traveled 125,935,769 miles during 33 spaceflights, including 12 missions to the International Space Station. Its final flight, STS-135, closed out the Space Shuttle Program era with a landing on July 21, 2011. Photo Credit: (NASA/Bill Ingalls)

NASA Administrator Charles Bolden, right, and NASA Kennedy Space Center Director Bob Cabana, left, quickly walk to the viewing bleachers at the NASA Kennedy Space Center Banana Creek viewing site in order to say a view words with visitors before they head to the Launch Control Center (LCC) for the planned launch of the space shuttle Atlantis from pad 39A on Friday, July 8, 2011, in Cape Canaveral, Fla. The launch of Atlantis, STS-135, is the final flight of the shuttle program, a 12-day mission to the International Space Station. Photo Credit: (NASA/Bill Ingalls)

Crowds are seen out the front window of the Astrovan carrying the STS-135 crew as it departs the NASA Kennedy Space Center, Operations and Checkout Building for launch pad 39A, on Friday, July 8, 2011 in Cape Canaveral, Fla. The launch of Atlantis, STS-135, is the final flight of the shuttle program, a 12-day mission to the International Space Station. Photo Credit: (NASA/Jerry Ross)

The space shuttle Endeavour is seen on launch pad 39a after the rollback of the Rotating Service Structure (RSS), Thursday, April 28, 2011, at Kennedy Space Center in Cape Canaveral, Fla. During the 14-day mission, Endeavour and the STS-134 crew will deliver the Alpha Magnetic Spectrometer (AMS) and spare parts including two S-band communications antennas, a high-pressure gas tank and additional spare parts for Dextre. Launch is targeted for Friday, April 29 at 3:47 p.m. EDT. Photo credit: (NASA/Bill Ingalls)

NASA Twitter followers attending the STS-135 Tweetup are seen through the helmet of a NASA space suit, Thursday, July 7, 2011, at Kennedy Space Center in Cape Canaveral, Fla. About 150 NASA Twitter followers attended the event. The STS-135 mission will be NASA's last space shuttle launch. Photo Credit: (NASA/Paul E. Alers)

NASA Shuttle Landing Facility (SLF) ground crew prepare for the arrival of the STS-134 crew in T-38 jets on Tuesday, April 26, 2011 at NASA's Kennedy Space Center in Cape Canaveral, Fla. During the 14-day mission, the space shuttle Endeavour and its crew will deliver the Alpha Magnetic Spectrometer (AMS) and spare parts including two S-band communications antennas, a high-pressure gas tank and additional spare parts for Dextre. Launch is targeted for Friday, April 29 at 3:47 p.m. EDT. Photo credit: (NASA/Bill Ingalls)