Two veteran spaceflyers and South Korea's first astronaut will say farewell to the crew of the International Space Station (ISS) Friday night and prepare to head home.

Expedition 16 commander Peggy Whitson, flight engineer Yuri Malenchenko and South Korean bioengineer So-yeon Yi will climb aboard their Russian-built Soyuz TMA-11 tonight and cast off from the station early Saturday.

The trio are aiming for a 4:30 a.m. EDT (0830 GMT) landing on the Central Asian steppes of Kazakhstan.

"I think we're going to be ready to go on Saturday," Whitson told this week via a video link, adding that she's looking forward to seeing family and friends again in person. "I know I'm not really looking forward to the gravity part down there."

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Whitson and Malenchenko are in the homestretch of a busy six months in orbit. During their flight, station astronauts performed five spacewalks and hosted three visiting NASA space shuttle crews that added new international modules, a laboratory and a massive Canadian robot to the ISS.

"I really do think that we've made a major to step to make the station more international," Whitson said.

Whitson and Malenchenko turned the station over to its new commander — Expedition 17 commander Sergei Volkov — and his crew on Thursday.

Volkov, the son of famed cosmonaut Alexander Volkov, is making his first spaceflight and launched April 8 with Yi and flight engineer Oleg Kononenko.

"We were able to talk a lot," Volkov said of his father. "He wished good luck for me, for my crew."

The third member of Volkov's crew, NASA astronaut Garrett Reisman, was already aboard the station as part of the Expedition 16 team. He will stay on until his replacement arrives in June.

Yi, meanwhile, is completing a 10-day science mission as part of a commercial agreement between the South Korean government and Russia's Federal Space Agency.

"Time flies so fast," Yi told reporters earlier this week. "Actually, now I don't want to go back. I want to fly longer than before."

With Whitson and Yi taking up two of the three seats aboard their Soyuz capsule, Saturday's landing will mark the first time women have outnumbered men aboard a spacecraft in flight. Malenchenko will command the Soyuz flight back to Earth.

"We were just talking about that," Whitson said, referring to Malenchenko. "I said 'Yuri, this time women out number men on a spacecraft!' ... But he's a great sport about it."

Returning to Earth

Preparations for Saturday's Soyuz landing will actually begin tonight at about 10:00 p.m. EDT (0200 April 19 GMT), when Whitson, Malenchenko and Yi will say goodbye to their Expedition 17 counterparts, shut themselves inside their spacecraft and prepare to cast off from the ISS.

The Soyuz is due to undock from an Earth-facing berth on the station's Russian-built Zarya module on Saturday at 1:06 a.m. EDT (0506 GMT), then fire its rocket engines at 3:40 a.m. EDT (0740 GMT) for about four minutes and 19 seconds in a braking maneuver to begin the descent back to Earth.

Whitson, who set a new record Wednesday for the most days in space by a U.S. astronaut, said she was looking forward to landing aboard a Russian Soyuz.

As the station's first female commander, she will have about 377 days in orbit across two ISS missions after tomorrow's planned touchdown, though her 2002 launch and landing occurred on a NASA shuttle.

"I think that will be personally satisfying," Whitson said of the Soyuz return. "Another advantage is that once we undock, we'll be home on the ground in a few hours. So I think it will be a quick trip."

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