The Expedition 27 prime and backup crew members pose for photographers in front of the Tsar Cannon at the Kremlin.

After laying flowers at the Kremlin Wall in Moscow March 11, 2011 as part of their ceremonial activities, the Expedition 27 prime and backup crew members pose for photographers in front of the Tsar Cannon at the Kremlin. From left to right are NASA astronaut Ron Garan, prime Expedition 27 flight engineer; Russian cosmonauts Andrey Borisenko and Alexander Samokutyaev; and their backups -- NASA astronaut Daniel Burbank, and Russian cosmonauts Anatoly Ivanishin and Anton Shklaperov. The three prime crew members will launch March 30 (Kazakhstan time) in their Soyuz TMA-21 spacecraft to the International Space Station. Photo credit: NASA/Stephanie Stoll