Going inside NASA's Vehicle Assembly Building

We get a rare look inside NASA Vehicle Assembly Building (VAB). Inside is a critical component of the planned Space Launch System (SLS), the pathfinder rocket. Weighing in at 228,000 pounds, the pathfinder is a full-scale mock-up of the rocket?s core stage and will provide the power necessary to send NASA?s Orion spacecraft beyond Earth?s orbit and to the Moon.