Space shuttle Discovery began its 3.4-mile journey to Launch Pad 39A at NASA’s Kennedy Space Center as it started its slow-motion exit from the Vehicle Assembly Building just before 7:30 p.m. EDT. The spacecraft — which was the third to join NASA’s shuttle fleet — will make its final flight on the STS-133 mission to the International Space Station, targeted for launch on Nov. 1. Stacked with its solid rocket boosters and external fuel tank on the mobile launcher platform, the shuttle’s slow roll atop a crawler-transporter should take about six and a half hours.