The U.S. space shuttle Atlantis has docked at the International Space Station Sunday.

The U.S. space agency NASA says the crews of both vessels are conducting a welcome ceremony later in the day, marking the 12th and final visit by Atlantis to the space station.

The combined crew members, 10 in all, will then begin more than a week of work, transferring a year's worth of supplies and equipment to the space station.

Upon its return to Earth next week, Atlantis will be retired and the 30-year U.S. space shuttle program will be over.

On Friday, an estimated crowd of 1 million people watched the historic final shuttle lift-off from the Kennedy Space Center in Florida.

NASA is ending the shuttle program to concentrate resources on deep-space exploration. The agency is working with several commercial U.S. aerospace companies to develop vehicles to replace the shuttles. Until then, Russia's Soyuz spacecraft will ferry U.S. astronauts to and from the ISS, while Russian, European and Japanese cargo spacecraft will continue their resupply and waste disposal missions to the station.

The four astronauts on Atlantis are Commander Chris Ferguson, Pilot Doug Hurley, Mission Specialist Rex Walheim and Mission Specialist Sandra Magnus. All four have flown on previous shuttle missions.