At the Vehicle Assembly Building at Kennedy Space Center, technicians practice and prepare to stack NASA’s Space Launch System rocket. The SLS fueled-up core stage weighs around 2.3 million pounds and measures 212 feet long.

At the Vehicle Assembly Building at Kennedy Space Center, technicians practice and prepare to stack NASA’s Space Launch System rocket. The SLS fueled-up core stage weighs around 2.3 million pounds and measures 212 feet long.