A closeup of the crawler-transporter underneath the mobile launcher platform with Space Shuttle Discovery on top as they approach the ramp to Launch Pad 39B for launch of mission STS-116. The mission is No. 20 to the International Space Station and construction flight 12A.1. The mission payload is the SPACEHAB module, the P5 integrated truss structure and other key components. The launch window for mission STS-116 opens Dec. 7. Photo credit: NASA/Jim Grossmann