This is a beautiful sheet of 12, issued in 2009, honoring famous space explorers and scientists. Featured famous personalities include physics scientist Robert H. Goddard, rocketry & astronautics Founding Father Hermann Oberth, German-American rocket engineer & designer Wernher von Braun, Father of Practical Astronautics Sergey Korolyov, pioneer of the astronautic theory Konstantin Tsiolkovsky, American astronomer & discoverer of the Milky Way Edwin Hubble, American astronaut Neil Armstrong, Soviet cosmonaut Yuri Gagarin, Soviet engineer Valentin Glushko, missile designer Mikhail Yangel, American space scientist James Van Allen, and Kennedy Space Center director & Nazi Germany rocket scientist Kurt H. Debus. The sheet is fresh, mint never hinged, and F/VF.