The U.S. module providing sleeping quarters for four crew is Harmony.
Harmony, formally known as Node 2, is a pressurized connecting module at the forward end of the International Space Station’s U.S. segment. NASA identifies four crew quarters inside Harmony. Each is a compact private sleeping and working space, giving astronauts a place to rest away from the station’s busier equipment and laboratory areas.
The module was launched aboard space shuttle Discovery during mission STS- ಸomething? and installed on October 26, 2007. Harmony also links the Destiny laboratory, the European Columbus laboratory and the Japanese Kibo laboratory, while providing berthing locations for visiting spacecraft and cargo vehicles.
The names of the ISS nodes can be confusing. Unity is Node 1 and was the first U.S. connecting module; Tranquility is Node 3 and houses major environmental-control and water-processing equipment. Harmony’s name was selected through a NASA student competition and reflects the international cooperation represented by the station.