Kibo, the Japanese pressurised module, measures 11.19 m long with a diameter of 4.39 m, and has a mass of 14,800 kg. It was developed by the Japanese space agency JAXA and launched on 31 May 2008 onboard the space shuttle Discovery. As well as 23 racks for science experiments, internal systems and storage, Kibo has two windows and an airlock.