The Biggest Spaceflight Moments of 2015

NASA spacecraft got up close and personal with two different dwarf planets, for example, and two private spaceflight companies pulled off rocket landings, suggesting that the long-sought dream of resuable launch vehicles could become a reality relatively soon. Pluto had remained largely mysterious since its 1930 discovery, because it's relatively small and orbits so far away (39 times farther from the sun than Earth does, on average). For instance, the best Pluto images taken by NASA's famous Hu