Video: Groundbreaking for commercial crew access tower

Towering more than 20 stories tall, the 8-million-pound mobile gantry at the Atlas 5 rocket’s launch pad at Vandenberg Air Force Base, California, was retracted into position late Friday for liftoff of NASA’s InSight mission to Mars.

The United Launch Alliance Atlas 5 rocket with the NROL-52 spacecraft aboard moved to the launch pad this morning for liftoff Saturday to serve the national interest. Liftoff is scheduled for 3:31 a.m. EDT (0731 GMT).

The first official launch weather outlook issued Tuesday by U.S. Air Force meteorologists predicts an 80 percent chance of favorable conditions for the predawn liftoff Saturday of SpaceX’s Crew Dragon spacecraft on a test flight to the International Space Station.