The world's third space tourist Gregory Olsen and two astronauts on board the Soyuz TMA-7 ship successfully entered the International Space Station (ISS) Monday morning three hours after the Russian spaceship carrying them docked with the ISS.

The Soyuz TMA-7 ship, carrying Olsen and Russian cosmonaut Valery Tokarev and NASA astronaut William McArthur, hurtled for two days in space after blasting off Saturday from the Baikonur cosmodrome in Kazakhstan.

The Soyuz TMA-7 supply ship docked with the ISS at 09:27 Moscow time (0527GMT), on Monday.

The spacecraft delivered to the ISS the crew of the 12th main mission -- Tokarev and McArthur, who will spend six months in space.

Sixty-year-old Gregory Olsen, the third space tourist on board the Soyuz, will also make a series of research experiments in the space, including crystal growth experiments in conditions of weightlessness, studies of the response of the human body in weightlessness, and measure of air humidity on Earth surface through spectrum.

Before Olsen there were two private space tourists -- Dennis Tito, of the United States and Mark Shuttleworth, of South Africa, who had spent a few days on the ISS in 2001 and 2002 respectively. Each of them paid 20 million US dollars for the tour. Olsen has paid the same price for his space travel.

He is reportedly to return to earth on Oct. 11 together with the current crew, Sergei Krikalev and John Phillips, who have been in orbit since April.