The Unity connecting module, also known as Node 1, is the first U.S.-built component of the International Space Station (ISS). It connects the Russian and United States segments of the station, and is where crew eat meals together. The module is cylindrical in shape, with six berthing locations (forward, aft, port, starboard, zenith, and nadir) facilitating connections to other modules. Unity measures in diameter, is long, made of steel, and was built for NASA by Boeing in a manufacturing facility at the Marshall Space Flight Center in Huntsville, Alabama. Unity is the first of the three connecting modules; the other two are Harmony and Tranquility. Launch and initial berthing Unity (with its two attached PMAs) was carried into orbit as the primary cargo of the Space Shuttle Endeavour (OV 105) on STS-88, the first Space Shuttle mission dedicated to assembly of the station. On 6 December 1998, the STS-88 crew mated the docking port of the PMA on the aft berthing port of Unity with the forward hatch of the already orbiting Zarya module. (Zarya was a mixed Russian-U.S. funded and Russian-built component launched a few days before aboard a Russian Proton launch vehicle from Baikonur, Kazakhstan.) This was the first connection made between two station modules. Connecting modules and visiting vehicles Unity has two axial and four radial Common Berthing Mechanism (CBM) ports. In addition to connecting to the Zarya module, Unity connects to the U.S. Destiny Laboratory Module (added on STS-98), the Z1 truss (an early exterior framework for the station added on STS-92), the PMA-3 (also added on STS-92), and the Quest Joint Airlock (added on STS-104). During STS-120 the Harmony module was temporarily berthed to the port-side hatch of Unity. Tranquility, with its multi-windowed cupola, was attached to Unity'''s port side during the STS-130 mission, and Leonardo was added to the nadir hatch during STS-133. In addition, the Leonardo and Raffaello Multi-Purpose Logistics Modules were each berthed to Unity on multiple missions. Nadir Forward Via PMA-2 Not via PMA-2 (Relocated to front of Destiny during STS-98 and again to the front of Harmony during STS-120.) Destiny, 2001–Present Aft Zarya (via PMA-1), 1998–Present Starboard Quest, 2001-Present Port Tranquility, 2010-Present Zenith Z1 truss, 2000-Present Details Essential space station resources such as fluids, environmental control and life support systems, electrical and data systems are routed through Unity to supply work and living areas of the station. More than 50,000