CAPE CANAVERAL, Fla. -- The Apollo/Saturn V Center at NASA's Kennedy Space Center in Florida hosted a celebration on the 40th anniversary of NASA's Apollo 15 mission. An elite gathering of Apollo-era astronauts were on hand for the event and panel discussion. Gerry Griffin, Apollo 15 flight director moderates the question-and-answer period with the panel. From left are: Apollo 15 astronaut backup support crew members, Joe Allen, Jack Schmitt, Vance Brand and Dick Gordon; Al Worden and Dave Scott. Worden circled the moon while Scott and the late Jim Irwin, the Lunar Module commander, made history when they became the first humans to drive a vehicle on the surface of the moon. They also provided extensive descriptions and photographic documentation of geologic features in the vicinity of the Hadley Rille landing site during their three days on the lunar surface. Photo credit: NASA/Kim Shiflett

CAPE CANAVERAL, Fla. -- The Apollo/Saturn V Center at NASA's Kennedy Space Center in Florida hosted a celebration on the 40th anniversary of NASA's Apollo 15 mission. Apollo 15 Commander Dave Scott and Command Module Pilot Al Worden and an elite gathering of Apollo-era astronauts were on hand for the event and panel discussion. Here, Gerry Griffin, Apollo 15 flight director, speaks to the invited guests. Worden circled the moon while Scott and the late Jim Irwin, the Lunar Module commander, made history when they became the first humans to drive a vehicle on the surface of the moon. They also provided extensive descriptions and photographic documentation of geologic features in the vicinity of the Hadley Rille landing site during their three days on the lunar surface. Photo credit: NASA/Kim Shiflett

CAPE CANAVERAL, Fla. -- The Apollo/Saturn V Center at NASA's Kennedy Space Center in Florida hosted a celebration on the 40th anniversary of NASA's Apollo 15 mission. Apollo 15 Commander Dave Scott and Command Module Pilot Al Worden and an elite gathering of Apollo-era astronauts were on hand for the event and panel discussion. Seen here are Al Worden (right), and Apollo 15 astronaut backup support crew members, Dick Gordon, Vance Brand and Jack Schmitt. Worden circled the moon while Scott and the late Jim Irwin, the Lunar Module commander, made history when they became the first humans to drive a vehicle on the surface of the moon. They also provided extensive descriptions and photographic documentation of geologic features in the vicinity of the Hadley Rille landing site during their three days on the lunar surface. Photo credit: NASA/Kim Shiflett

CAPE CANAVERAL, Fla. -- The Apollo/Saturn V Center at NASA's Kennedy Space Center in Florida hosted a celebration on the 40th anniversary of NASA's Apollo 15 mission. Apollo 15 Commander Dave Scott and Command Module Pilot Al Worden and an elite gathering of Apollo-era astronauts were on hand for the event and panel discussion. Here, sharing a light moment are from left, Apollo 15 astronaut support crew members, Joe Allen, Jack Schmitt and Vance Brand. Worden circled the moon while Scott and the late Jim Irwin, the Lunar Module commander, made history when they became the first humans to drive a vehicle on the surface of the moon. They also provided extensive descriptions and photographic documentation of geologic features in the vicinity of the Hadley Rille landing site during their three days on the lunar surface. Photo credit: NASA/Kim Shiflett

CAPE CANAVERAL, Fla. -- The Apollo/Saturn V Center at NASA's Kennedy Space Center in Florida hosted a celebration on the 40th anniversary of NASA's Apollo 15 mission. Apollo 15 Commander Dave Scott and Command Module Pilot Al Worden and an elite gathering of Apollo-era astronauts were on hand for the event and panel discussion. Seen here are Apollo 15 astronaut backup support crew members, Jack Schmitt (left), Vance Brand and Dick Gordon; Al Worden and Dave Scott. Worden circled the moon while Scott and the late Jim Irwin, the Lunar Module commander, made history when they became the first humans to drive a vehicle on the surface of the moon. They also provided extensive descriptions and photographic documentation of geologic features in the vicinity of the Hadley Rille landing site during their three days on the lunar surface. Photo credit: NASA/Kim Shiflett

CAPE CANAVERAL, Fla. -- The Apollo/Saturn V Center at NASA's Kennedy Space Center in Florida hosted a celebration on the 40th anniversary of NASA's Apollo 15 mission. Apollo 15 Commander Dave Scott and Command Module Pilot Al Worden and an elite gathering of Apollo-era astronauts were on hand for the event and panel discussion. Here, Apollo 11 Commander Neil Armstrong speaks to the invited guests. In the background is a model of the Lunar Module, part of the lander portion of the Apollo spacecraft. Worden circled the moon while Scott and the late Jim Irwin, the Lunar Module commander, made history when they became the first humans to drive a vehicle on the surface of the moon. They also provided extensive descriptions and photographic documentation of geologic features in the vicinity of the Hadley Rille landing site during their three days on the lunar surface. Photo credit: NASA/Kim Shiflett

CAPE CANAVERAL, Fla. -- The Apollo/Saturn V Center at NASA's Kennedy Space Center in Florida hosted a celebration on the 40th anniversary of NASA's Apollo 15 mission. Apollo 15 Commander Dave Scott, Command Module Pilot Al Worden and an elite gathering of Apollo-era astronauts were on hand for the event and panel discussion. Here, Apollo 11 Commander Neil Armstrong speaks to the invited guests. Worden circled the moon while Scott and the late Jim Irwin, the Lunar Module commander, made history when they became the first humans to drive a vehicle on the surface of the moon. They also provided extensive descriptions and photographic documentation of geologic features in the vicinity of the Hadley Rille landing site during their three days on the lunar surface. Photo credit: NASA/Kim Shiflett

CAPE CANAVERAL, Fla. -- The Apollo/Saturn V Center at NASA's Kennedy Space Center in Florida hosted a celebration on the 40th anniversary of NASA's Apollo 15 mission. Apollo 15 Commander Dave Scott, Command Module Pilot Al Worden and an elite gathering of Apollo-era astronauts were on hand for the event and panel discussion. Here, Apollo 16 Lunar Module Pilot Charlie Duke welcomes the invited guests and introduces the guests of honor. Worden circled the moon while Scott and the late Jim Irwin, the Lunar Module commander, made history when they became the first humans to drive a vehicle on the surface of the moon. They also provided extensive descriptions and photographic documentation of geologic features in the vicinity of the Hadley Rille landing site during their three days on the lunar surface. Photo credit: NASA/Kim Shiflett

CAPE CANAVERAL, Fla. -- The Apollo/Saturn V Center at NASA's Kennedy Space Center in Florida hosted a celebration on the 40th anniversary of NASA's Apollo 15 mission. Apollo 15 Commander Dave Scott (right) and Command Module Pilot Al Worden and an elite gathering of Apollo-era astronauts were on hand for the event and panel discussion. Worden circled the moon while Scott and the late Jim Irwin, the Lunar Module commander, made history when they became the first humans to drive a vehicle on the surface of the moon. They also provided extensive descriptions and photographic documentation of geologic features in the vicinity of the Hadley Rille landing site during their three days on the lunar surface. Photo credit: NASA/Kim Shiflett

CAPE CANAVERAL, Fla. -- The Apollo/Saturn V Center at NASA's Kennedy Space Center in Florida hosted a celebration on the 40th anniversary of NASA's Apollo 15 mission. Apollo 15 Commander Dave Scott and Command Module Pilot Al Worden and an elite gathering of Apollo-era astronauts were on hand for the event and panel discussion. Here, Al Worden with microphone in hand, speaks to the invited guests. Worden circled the moon while Scott and the late Jim Irwin, the Lunar Module commander, made history when they became the first humans to drive a vehicle on the surface of the moon. They also provided extensive descriptions and photographic documentation of geologic features in the vicinity of the Hadley Rille landing site during their three days on the lunar surface. Photo credit: NASA/Kim Shiflett

Astronaut James Lovell (Apollo 8 Apollo 13), center, flanked by Walt Cunningham (Apollo 7), left, and David Scott (Apollo 9 Apollo 15) responds during the 40th anniversary of the Apollo 11 mission and the walk on the moon press conference, Monday, July 20, 2009, at NASA Headquarters in Washington. Photo Credit: (NASA/Paul E. Alers)

Apollo astronauts from left, Walt Cunningham (Apollo 17), James Lovell (Apollo 8 Apollo 13), David Scott (Apollo 9 Apollo 15), Buzz Aldrin (Apollo 11), Charles Duke (Apollo 16), Thomas Stafford (Apollo 10) and Eugene Cernan (Apollo 17) are seen during the 40th anniversary of the Apollo 11 mission and the walk on the moon press conference, Monday, July 20, 2009, at NASA Headquarters in Washington. Photo Credit: (NASA/Paul E. Alers)

Apollo astronauts from left, Walt Cunningham (Apollo 17), James Lovell (Apollo 8 Apollo 13), David Scott (Apollo 9 Apollo 15), Buzz Aldrin (Apollo 11), Charles Duke (Apollo 16), Thomas Stafford (Apollo 10) and Eugene Cernan (Apollo 17) are seen during the 40th anniversary of the Apollo 11 mission and the walk on the moon press conference, Monday, July 20, 2009, at NASA Headquarters in Washington. Photo Credit: (NASA/Paul E. Alers)

Apollo astronauts from left, Walt Cunningham (Apollo 17), James Lovell (Apollo 8 Apollo 13), David Scott (Apollo 9 Apollo 15), Buzz Aldrin (Apollo 11), Charles Duke (Apollo 16), Thomas Stafford (Apollo 10) and Eugene Cernan (Apollo 17) are seen during the 40th anniversary of the Apollo 11 mission and the walk on the moon press conference, Monday, July 20, 2009, at NASA Headquarters in Washington. Photo Credit: (NASA/Paul E. Alers)

ISS044E013678 (07/15/2015) --- On July 15, 2015 aboard the International Space Station, Expedition 44 crew memebrs Scott Kelly of NASA (left), Expedition Commander and Russian cosmonaut Gennady Padalka (middle), and Russian cosmonaut Mikhail Kornienko (right) commemorated the 40th anniversary of the joint Apollo-Soyuz mission.

KENNEDY SPACE CENTER, FLA. - Former astronaut Gordon Cooper shares his experiences with the audience in KSC's Apollo/Saturn V Center during the celebration of the 40th anniversary of American spaceflight. Cooper, flying in the Faith 7 spacecraft, was the fourth American in space. The spacecraft was launched May 15, 1963

CAPE CANAVERAL, Fla. – At the Apollo/Saturn V Center at NASA's Kennedy Space Center in Florida, Apollo astronaut Al Worden is introduced during NASA's 40th Anniversary of Apollo Celebration of the July 1969 launch and landing on the moon. He was joined by seven others involved in the program. Worden was command module pilot for Apollo 15 in 1971 and logged 38 minutes in extravehicular activity outside the command module. Photo credit: NASA/Kim Shiflett

CAPE CANAVERAL, Fla. – At the Apollo/Saturn V Center at NASA's Kennedy Space Center in Florida, Apollo astronaut Al Worden shares his experiences with an eager crowd gathered for NASA's 40th Anniversary of Apollo Celebration of the July 1969 launch and landing on the moon. Worden was command module pilot for Apollo 15 in 1971 and logged 38 minutes in extravehicular activity outside the command module. Photo credit: NASA/Kim Shiflett

CAPE CANAVERAL, Fla. – Gemini 8, Apollo 9 and 15 astronaut David Scott speaks to guests gathered for the Astronaut Scholarship Foundation's dinner at the Radisson Resort at the Port in Cape Canaveral celebrating the 40th anniversary of Apollo 17. The gala commemorating the anniversary of Apollo 17 included mission commander Eugene Cernan and other astronauts who flew Apollo missions. Launched Dec. 7, 1972, Cernan and lunar module pilot Harrison Schmitt landed in the moon's Taurus-Littrow highlands while command module pilot Ronald Evans remained in lunar orbit operating a scientific instrument module. For more information, visit http://www-pao.ksc.nasa.gov/history/apollo/apollo-17/apollo-17.htm Photo credit: NASA/Kim Shiflett