STS-129 (ISS assembly flight ULF3) was a NASA Space Shuttle mission to the International Space Station (ISS) flown by Atlantis. STS-129 focused on staging spare components outside the station. The 11-day flight included three spacewalks. The payload bay carried two large ExPRESS Logistics Carriers holding two spare gyroscopes, two nitrogen tank assemblies, two pump modules, an ammonia tank assembly, a spare latching end effector for the station's robotic arm, a spare trailing umbilical system for the Mobile Transporter, and a high-pressure gas tank. STS-129 was the first flight of an ExPRESS Logistics Carrier.