A Minuteman III missile engine is loaded into a truck for transport to another building for X-raying before being torn down and rebuilt. The Air Force's missile command-and-control structure has been the subject of several recent scandals. Douglas C. Pizac/AP hide caption

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An Iranian security guard directs media at the Bushehr nuclear power plant in 2010. Iran and negotiators from six world powers are in Vienna trying to work out a long-term deal on Iran's nuclear program. Vahid Salemi/AP hide caption

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First Lt. Patrick Romanofski (center) and 2nd Lt. Andrew Beckner (left) practice the launch of nuclear weapons. Promotions are now more strongly influenced by hands-on performance in this simulator. R.J. Oriez/U.S. Air Force hide caption

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Anti-nuclear activists (from left) Gregory Boertje-Obed, Sister Megan Rice and Michael Walli, pictured Feb. 6 in Knoxville, Tenn., were sentenced to prison terms on Tuesday for the 2012 break-in at Y-12 National Security Complex in Oak Ridge. Linda Davidson/The Washington Post/Getty Images hide caption

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The National Ignition Facility's 192 laser beams focus onto a tiny target. LLNL hide caption

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Negotiators at their round table in Geneva, where talks are being held about Iran's nuclear ambitions. Denis Balibouse /Reuters/Landov hide caption

itoggle caption Denis Balibouse /Reuters/Landov

U.S. Secretary of Defense Leon Panetta is given a traditional Maori welcome onto the grounds of the Government House on Friday in Auckland, New Zealand. Phil Walter/Getty Images hide caption

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International Atomic Energy Agency Director-General Yukiya Amano earlier today in Vienna, after his return from talks in Tehran. Dieter Nagl /AFP/Getty Images hide caption

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