Just look at the size of those nozzles! Well they have to be big, they will be at the base of the world’s most powerful rocket:
NASA — Space Launch System (SLS) solid rocket booster prime contractor Orbital ATK recently completed work at its Utah facilities on the booster nozzles for Exploration Mission-1 (EM-1), the first flight of SLS and the Orion spacecraft. SLS, the world’s most powerful rocket, and Orion will take humans on deep space missions, and the boosters provide most of the power to get the spacecraft off the ground. The powerhouse SLS five-segment solid rocket boosters are the largest ever built for flight and will provide more than 75 percent of the thrust during the first two minutes of spaceflight. Here, technicians are putting the finishing touches on the exit cones’ paint, including photogrammetric markings that will help engineers assess clearances between the boosters and ground structures during the initial moments after liftoff. At Kennedy Space Center in Florida during the integration phase of the program, the exit cones will be mated with the rest of the nozzle assemblies, which are also complete. During spaceflight, the booster nozzles direct the expanding gases from the burning solid propellant downward, helping the heavy-lift vehicle escape Earth’s gravity and send Orion to lunar orbit.
Image credit: Orbital ATK