Stock Photo - 03/25/2000 __ The Space Shuttle Atlantis, atop the mobile launcher platform and crawler_transporter, begins the climb up the ramp to Launch Pad 39A. The crawler_transporter carries its cargo at 1 mph, taking about five hours to cover the 3.4 miles from the Vehicle Assembly Building to the launch pad. A leveling system on the crawler_transporter keeps the top of the Space Shuttle vertical, especially negotiating the ramp leading to the launch pads and when it is raised and lowered on pedestals at the pad. Liftoff of Atlantis on mission STS_101 is scheduled for April 17 at 7:03 p.m. EDT. STS_101 is a logistics and resupply mission for the International Space Station, to restore full redundancy to the International Space Station power system in preparation for the arrival of the next pressurized module, the Russian_built Zvezda