STS-127 Commander Mark Polansky checks the fit of his helmet before heading to Launch Pad 39A for launch.

In the Operations and Checkout Building at NASA's Kennedy Space Center in Florida, STS-127 Commander Mark Polansky checks the fit of his helmet before heading to Launch Pad 39A for launch. Liftoff of space shuttle Endeavour is scheduled for 6:03 p.m. EDT. 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