The Institute for Science and International Security (ISIS), a nonprofit that monitors the Iranian nuclear program, published May 9, 2012, on its website this satellite photo of Iran's Parchin military base. (Courtesy of isis-online.org)

The Institute for Science and International Security (ISIS), a nonprofit that monitors the Iranian nuclear program, published May 9, 2012, on its website this satellite photo of Iran's Parchin military base. (Courtesy of isis-online.org)