The space shuttle Discovery landed safely at the Kennedy Space Centre in Florida on Saturday.
Commander Lee Archambault guided the shuttle to a picture-perfect landing at 1914 GMT, ending the shuttle's 13-day mission to the International Space Station (ISS).
"Welcome home after a mission to bring the ISS to full power," the NASA ground crew said, adding a special welcome to astronaut Sandra Magnus, who returned to Earth after spending 129 days living aboard the ISS.
"Thank you very much. It's good to be back home," Archambault replied.
The landing had been delayed by around an hour and a half due to poor weather from an originally scheduled 1740 GMT touchdown, due to thick cloud cover.
The mission astronauts installed a fourth set of solar panels on the ISS, completing the power plant needed to double the station's electrical generating capacity.
The power allows the station to sustain six long-term residents instead of the current crew of three, the crew could be expanded as early as May.
The shuttle crew completed three spacewalks during its mission, including installation of the last solar panels.
Earlier on Saturday, a Russian Soyuz craft docked at the ISS, bringing two more ISS crew members and space tourist Charles Simonyi, a co-founder of Microsoft taking his second flight in space.
Cosmonaut Gennady Padalka and US astronaut Michael Barratt will replace Yury Lonchakov and commander Mike Fincke. They will join Japanese astronaut Koichi Wakata, the first long-term Japanese crew member on the ISS, who arrived aboard the Discovery.
Magnus, Wakata's predecessor on the ISS crew, returned home with the Discovery.
The shuttle is also carrying scientific experiments conducted aboard ISS and samples from a machine designed to turn urine and sweat into drinkable water.
Discovery delivered a new machine after an earlier version kept breaking on an earlier shuttle mission. NASA will take about a month to analyse the sample to make sure the water is safe before the expansion of the ISS crew to six.