Shannon Walker speaks to workers and guests during an employee event for the mobile launcher move.

NASA astronaut Shannon Walker speaks to workers and guests during an employee event for the mobile launcher move to the Vehicle Assembly Building (VAB) on Sept. 7, 2018, at NASA's Kennedy Space Center in Florida. The mobile launcher, atop crawler-transporter 2, began its trek from Launch Pad 39B along the crawlerway after undergoing a fit check and several days of systems testing with the pad. This is the first time that the modified mobile launcher made the trip to the pad. The 380-foot-tall mobile launcher is equipped with the crew access arm and several umbilicals that will provide power, environmental control, pneumatics, communication and electrical connections to the agency's Space Launch System and Orion spacecraft. The mobile launcher will spend seven months in the VAB undergoing testing. Exploration Ground Systems is preparing the ground systems necessary to launch SLS and Orion on Exploration Mission-1, missions to the Moon and on to Mars.