The astronauts and their ground support had to toil while the rest of the United States marked Thanksgiving day, one of the most important national holidays of the year for Americans.

"We all miss our families and we're sorry that you all are having to work on Thanksgiving, but it's all for a good cause," astronaut Michael Lopez-Alegria told the technicians to the mission control in Houston.

The shuttle icon on the giant screen at ground control in Houston was replaced with a Turkey for the day.

Lopez-Alegria and John Herrington, the first native American astronaut, spent six hours and 10 minutes in space to connect fluid lines that will provide air conditioning to part of the 390 million dollar space station.

In a delicate operation, Herrington was carried high above space station to guide a 270 kilogramme (600 pound) rail cart used by astronauts on the station's mini-railroad from one side of the station to the other.

There are two carts on the track which can be used separately by the astronauts or linked to a trolley to carry equipment from one site on the station to another.

Astronauts are building a girder more than 100 meters (330 feet) long which will support some 4,000 square meters (43,000 square feet) of solar panels that will supply the station's energy.

The third and last space walk of this mission is scheduled for Saturday.

Endeavour will leave the space station on Monday and bring back to Earth two Russians and an American who have been on the station for almost six months.

SPACE.WIRE