In High Bay 3 of the Vehicle Assembly Building at NASA’s Kennedy Space Center in Florida, workers assist as the right-hand forward segment is lowered onto the center forward segment on the mobile launcher (ML) for the Space Launch System (SLS) on March 3, 2021. Workers with Exploration Ground Systems and contractor Jacobs teams stacked the twin five-segment boosters on the ML over a number of weeks. When the core stage arrives, it will join the boosters on the mobile launcher, followed by the interim cryogenic propulsion stage and Orion spacecraft. Manufactured by Northrop Grumman in Utah, the twin boosters provide more than 75 percent of the total SLS thrust at launch. Marshall Space Flight Center in Huntsville, Alabama, manages the SLS. Under the Artemis program, NASA will land the first woman and the next man on the Moon. The first in a series of increasingly complex missions, Artemis I will test the Orion spacecraft and SLS as an integrated system ahead of crewed flights to the Moon.