the largest, most sophisticated and powerful spacecraft
ever built when its second year of occupancy began in 2001,
the International Space Station grew by more than 25,400
kilograms (56,000 pounds) in components added during the
following 12 months.
the first two years of permanent occupancy, the station
grew by more than 90,718 kilograms (200,000 pounds), and
its internal volume increased from that of an efficiency
apartment to a three-bedroom house.
2002, construction began on the station's backbone, a truss
structure that eventually will support almost an acre of
solar panels to provide more power for orbital research
than ever before.