(From left) Historian Douglas Brinkley, Astronauts Chris Cassidy (US), Paolo Nespoli (Italy), Tracy Caldwell-Dyson (US), Koichi Wakata (Japan), and Oleg Kotov (Russia) participate in a panel discussion during the JFK Space Summit, celebrating the 50th anniversary of the moon landing, at the John F. Kennedy Library in Boston, the US on Wednesday. Photo: VCG