The STS-127 crew members wave to spectators and pause for photographers before leaving for Launch Pad 39A in the Astrovan (behind them). From left are Mission Specialists Dave Wolf, Christopher Cassidy, Tom Marshburn, Tim Kopra and Julie Payette of the Canadian Space Agency, Pilot Doug Hurley and Commander Mark Polansky. Today will be the sixth launch attempt for the STS-127 mission. The launch was scrubbed on June 13 and June 17 when a hydrogen gas leak occurred during tanking due to a misaligned Ground Umbilical Carrier Plate. The mission was postponed July 11, 12 and 13 due to weather conditions near the Shuttle Landing Facility at Kennedy that violated rules for launching, and lightning issues. Endeavour will deliver the Japanese Experiment Module's Exposed Facility and the Experiment Logistics Module-Exposed Section in the final of three flights dedicated to the assembly of the Japan Aerospace Exploration Agency's Kibo laboratory complex on the International Space Station. Photo credit: NASA/ Kim Shiflett