The left-hand booster forward assembly for NASA’s Space Launch System is lowered by crane onto the center forward segment on the mobile launcher (ML) in High Bay 3 of the Vehicle Assembly Building at Kennedy Space Center in Florida on March 1, 2021. Exploration Ground Systems and contractor Jacobs teams have been stacking 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.