If you would like to see more articles like this please support our coverage of the space program by becoming a Spaceflight Now Member. If everyone who enjoys our website helps fund it, we can expand and improve our coverage further. The twin solid rocket boosters for the Artemis 1 mission are stacked on the SLS Mobile Launcher inside High Bay 3 of the Vehicle Assembly Building. Credit: NASA/Isaac Watson The twin 177-foot-tall (54-meter) solid-fueled boosters for the first flight of NASA’s Space Launch System have been stacked inside the Vehicle Assembly Building at the Kennedy Space Center to await arrival of the rocket’s cryogenic core stage, which is set for a second engine test on a firing stand in Mississippi later this month.