JSC2007-E-18096 (9 April 2007) --- Astronauts Pamela A. Melroy (left), STS-120 commander; Daniel M. Tani, Expedition 16 flight engineer; and George D. Zamka, STS-120 pilot, enjoy a light moment as they await the start of a training session in the Space Vehicle Mockup Facility at Johnson Space Center. Tani is scheduled to join Expedition 16 as flight engineer after launching to the International Space Station on mission STS-120 and is scheduled to return home on mission STS-122.