premise: The solar arrays themselves were launched and installed over a period of eleven years, more slowly than originally planned, with the station continually suffering from a shortage of power as a result. The first two arrays, each 38 m2 (409 ft2) in area, were launched on the core module, and together provided a total of 9 kW of power. A third, Dorsum (anatomy) panel was launched on Kvant-1 and mounted on the core module in 1987, providing a further 2 kW from a 22 m2 (237 ft2) area. Kvant-2, launched in 1989, provided two 10 m (32.8 ft) long panels which supplied 3.5 kW each, whilst Kristall was launched with two collapsible, 15 m (49.2 ft) long arrays (providing 4 kW each) which were intended to be moved to Kvant-1 and installed on mounts which were attached during a spacewalk by the Soyuz TM-11 crew in 1991.
hypothesis:  year was the first solar arrays installed