The U.S. space shuttle Discovery is returning to Earth after completing an eight-day resupply mission to the International Space Station.

The crews of the two spacecraft embraced and shook hands Tuesday before closing the hatches and undocking the shuttle from the station.

U.S. astronaut Tim Kopra ended a mission on the station that began in July and joined Discovery for the flight back to Earth. Another American astronaut, Nicole Stott, replaced him as one of the six crew members aboard the station.

Discovery brought almost 8,000 kilograms of equipment to the station, including scientific experiments involving mice and an ammonia tank for the station's cooling system. The shuttle is due to land Thursday at the Kennedy Space Center in the southeastern state of Florida.

NASA plans six more shuttle flights before retiring the fleet next year. After that, Russian and private space programs will be used to deliver supplies to the space station.

Some information for this report was provided by AP.