From left to right, Lili Villareal, Operations Flow Manager, Exploration Ground Systems; Charlie Duke, NASA Astronaut (former); and Dottie Duke, wife of Charlie Duke, view the massive Space Launch System (SLS) core stage in Kennedy Space Center's Vehicle Assembly Building (VAB) in Florida on May 10, 2021. Inside the VAB, the SLS core stage is being prepared for integration with the completed stack of twin solid rocket boosters atop the mobile launcher ahead of the Artemis I launch. The first in a series of increasingly complex missions, Artemis I will test SLS and Orion as an integrated system prior to crewed flights to the Moon.