The ISS common hatch is the largest doorway to be launched into space. The 4-foot-wide hatch makes it possible to bring in equipment as big as a standard size refrigerator.
This 53-inch square hatch was manufactured by Boeing for the International Space Station. "Common" to the US labs and nodes, as well as the international labs such as ESA's Columbus, the interior side of the hatch is also referred to as the dome side, due to its smooth, clean, convex curved appearance. Likewise, the exterior is called the ribbed side given its 24 radial ribs. Pressurization puts 20 tons of force on the hatch, which is not uniformly distributed around the edges due to its square shape. "The large hatch truly is an unsung hero of the ISS design!" said station astronaut Dan Bursch in an interview with MSNBC.