This is the first NASA mission by SpaceX that includes an upgraded version of the Falcon 9. Outwardly, the biggest change is an arrangement of eight engines in a circle around the center engine. Previously, the nine engines were built in three rows of three. SpaceX says the octaweb reduces the length and weight of the Falcon 9 thrust structure and streamlines manufacturing of the first stage. While this is the first NASA mission with an octaweb first stage, the engine pattern flew successfully during several previous SpaceX missions launching commercial payloads.