Photo - This undated image made available by NASA and photographed by the Expedition 28 crew aboard the International Space Station, shows the moon, at center with the limb of Earth near the bottom transitioning into the orange-colored troposphere, the lowest and most dense portion of the Earth's atmosphere.  A team of former NASA executives are launching a private venture to send people to the moon for $1.5 billion. The newly formed business is offering countries a two-person trip to the moon, either for research or national prestige. The venture was announced Wednesday, Dec. 6, 2012. (AP Photo/NASA)