Related: US millionaire ready for space tour

The Russian Soyuz TMA-7 rocket is transported to its launch pad at Baikonur cosmodrome in Kazakhstan September 29, 2005.(Photo: Xinhua/AFP) MOSCOW, Oct. 11(Xinhuanet)--A Russian spacecraft carrying the outgoing crew of the International Space Station and the world's third space tourist undocked with the station Tuesday, embarking on its flight back to Earth.

Riding home in the capsule are Russian cosmonaut Sergei Krikalev, US astronaut John Phillips and space traveler Gregory Olsen, who have spent 10 days in space as the world's third private citizen to visit the station.

They entered the Soyuz ship three hours before their flight back to Earth, which was scheduled for 2143 GMT Monday, the Mission Control outside Moscow said.

They are expected to land on the barren steppes of Kazakhstan at 0109 GMT Tuesday.

"In the three hours before the undocking, the cosmonauts are tocheck the ship's systems, don the spacesuits in the cramped quarters of the descent craft of the Soyuz TMA-6, take their places and wait for the decisive moment of the command to separatefrom the station and set off on the flight back to the ground," Mission Control spokesman Valery Lyndin said, according to the Itar-Tass news agency.

Krikalev and Phillips have logged 179 days in orbit and will leave behind Russian cosmonaut Valery Tokarev and NASA astronaut William McArthur, who reached the station on Oct. 3 after hurtlingtwo days in space and will be busy keeping the station ticking over for the next six months.

Olsen, traveling back with them after a 10-day stay in space, was preceded by American Dennis Tito and South African Mark Shuttleworth, who had spent a few days on the ISS in 2001 and 2002respectively after paying 20 million US dollars apiece for the tour. Olsen reportedly paid the same price.

Russia's space program has been the ISS' lifeline for more thantwo years, ferrying crews and cargo since the US shuttle Columbia disintegrated as it returned to Earth in 2003. All seven astronauts aboard Columbia perished.

The US shuttle Discovery briefly visited the orbiting lab in July but concerns over the foam insulation on the shuttle's external fuel tank prompted NASA to keep the shuttle fleet grounded. Enditem