BAIKONUR, Kazakhstan (AP) -- A Russian and an American preparing to blast off for the International Space Station said Thursday that the highlight of their mission will be welcoming a U.S. space shuttle to the station after a two-year absence.

Sergei Krikalev and John Phillips are to launch at sunrise Friday from Baikonur Cosmodrome, the Russian space program's manned-launch facility in the desolate steppes of Kazakhstan, for a six-month stay on the ISS.

Also aboard the Soyuz spacecraft for the two-day flight to the ISS will be Italian Roberto Vittori, flying for the European Space Agency. He is to stay on the station for eight days and return April 25 with Russian Salizhan Sharipov and American Leroy Chiao, who have been on the orbiting lab since October.

Since the space shuttle Columbia disintegrated upon re-entry on Feb. 1, 2003, shuttle flights have been suspended, leaving the Soyuz as the only way of getting astronauts to the ISS. NASA aims to revive flights as early as May 15, with a mission by Discovery to the ISS.

The Columbia disaster was due to a failure of insulating tiles on the shuttle's exterior, which are put under extreme heat on both takeoff and landing. A key task for Krikalev and Phillips will be to observe the condition of the tiles as the Discovery approaches the ISS.

"Sergei and I will be taking part in the measures that have been taken since the Columbia to ensure the safety of the shuttle, and those measures are many. But our particular part will be conducting a photo survey of the exterior of the shuttle while it is maneuvering immediately below us prior to docking," Phillips said at a news conference.

"I think the eyes of the world are going to be upon the shuttle crew at that moment, and will be a little on us too, and I'm really proud to be a part in that," he said.

Asked what feelings he expected to have when the shuttle docks with the ISS, Phillips said, "I think I will think that this begins a big sprint.''

Krikalev said he expected to be moved by the shuttle arrival.

"Every person is a significant addition and when the shuttle comes it will be a big celebration. They're not only bringing material for experiments, material for the station, food, water, gas, but they're bringing emotions," he said, speaking like the others from behind glass in a separate room to avoid contamination.

The two years of dependence on the Soyuz for flights to the ISS has put a strain on the underfunded Russian space agency but also has helped augment its reputation.

"I think the fact that we've been able to carry on since the Columbia accident using Russian-supplied people and supplies demonstrates the strength of our partnership," Phillips said. "But without the shuttle flying, it's impossible to continue the buildup of the station."

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