Beverly Case, a handling engineer on the Test, Operations and Support Contract at NASAs Kennedy Space Center in Florida, readies the Space Launch System (SLS) solid rocket boosters for mating to the rockets two aft skirts on June 19, 2020, inside Kennedys Rotation, Processing and Surge Facility. Together, the twin boosters provide more than 75 percent of the total SLS thrust at launch. Manufactured by Northrop Grumman in Promontory, Utah, the boosters arrived at Kennedy via train. This cross-country journey was an important milestone for the agencys Artemis I launch. The first in a series of increasingly complex missions, Artemis I will test the Orion spacecraft and SLS as an integrated system prior to crewed missions to the Moon. Once the boosters are mated with the aft skirts, they will be moved to the Vehicle Assembly Building for stacking on the mobile launcher.