Space shuttle Discovery and its seven-member crew lifted off from NASA's Kennedy Space Center at 7:43 p.m. EDT Sunday.
Discovery is carrying the space station's fourth and final set of solar array wings. The arrays will provide the electricity to fully power science experiments and support the station's expanded crew of six.
During the 13-day mission, the crew will install the solar array. The crew will also deliver supplies and hardware, and replace a broken machine that turns urine into drinking water.
Discovery should reach the space station Tuesday.
Problems with hydrogen valves delayed the launch for weeks, in February and a hydrogen leak during fueling prevented the launch Wednesday.