Zarya and Unity. View of the first two modules of the international Space Station (ISS). At lower centre is the Russian-built Zarya control module which is joined to the United States- built connecting module Unity (upper centre). The image was taken during Endeavour Space Shuttle mission STS-088 (4-15 December 1998). During the mission Zarya, which was launched in November 1998, was captured by Endeavour's remote manipulator system (RMS). Unity was then attached to Zarya and the two modules were released. The ISS will be completed in 2003 and will be used to study the effect of weightlessness on materials & biological tissues.