Astronauts from Russia, Japan and the United States Thursday docked successfully with the International Space Station under six hours after they launched, NASA television showed.

The Soyuz TMA 17M rocket -- carrying cosmonaut Oleg Kononenko, US astronaut Kjell Lindgren and Kimiya Yui of Japan -- had roared skyward from Russia's Baikonur cosmodrome in the barren Kazakh steppe at 2102 GMT.

After a fly-around at around 350 meters (1,150 feet), the rocket manuevered to a rendezvous with the ISS, at 10:46 EST (0246 GMT Thursday).

"We have contact," a NASA announcer said, as the craft soared high above the coast of Ecuador, 402 kilometres (250 miles) over the Pacific.

One solar array -- a type of power supply that captures energy from the sun -- did not deploy on time, but this did not affect the rocket's flight as the others were still operating, the US space agency said.

Scientists and space enthusiasts around the world were watching the launch closely, and with some concern, since the mission had been delayed by two months because of a Russian rocket failure.

Russia was in May forced to put all space travel on hold after the unmanned Progress freighter taking cargo to the ISS crashed back to Earth in late April.

The doomed ship lost contact with Earth and burned up in the atmosphere. The failure, which Russia has blamed on a problem in a Soyuz rocket, also forced a group of astronauts to spend an extra month aboard the ISS.

A workhorse of space that dates back to the Cold War, the Soyuz is used for manned and unmanned flights.

Ahead of the liftoff, the three men met with 81-year-old cosmonaut Alexei Leonov, the first man to walk in space and one of the Apollo-Soyuz commanders.

Sending the first man into space in 1961 and launching the first sputnik satellite four years earlier are among key accomplishments of the Russian space program and remain a major source of national pride in the country.

But over the past few years, Russia has suffered several major setbacks, notably losing expensive satellites and unmanned supply ships to the ISS.