Celebrating scientists in the main control room appear on a video screen at the European Space Agency after the first unmanned spacecraft Philae landed on a comet called 67P/Churyumov-Gerasimenko, in  Darmstadt, Germany, Wednesday, Nov. 12, 2014. Europe's Rosetta space probe was launched in 2004 with the aim of studying the comet and learning more about the origins of the universe. (AP Photo/Michael Probst)

Photos: Spacecraft lands on comet

The European Space Agency celebrated a cosmic touchdown Wednesday by successfully landing a spacecraft on a comet.