Two Russian cosmonauts and American space tourist Richard Garriott are set to cast off from the International Space Station Thursday night for the return to Earth, and they're hoping for a smooth ride home.

Space station commander Sergei Volkov and flight engineer Oleg Kononenko are due to undock their Russian Soyuz TMA-12 spacecraft from the station at about 8:15 p.m. EDT (0015 Oct. 24 GMT) and land on the Central Asian steppes of Kazakhstan with Garriott at about 11:36 p.m. EDT (0336 GMT).

But unlike the last two Soyuz landings, the spaceflyers are confident they'll have an uneventful ride home.

"About our vehicle, we're absolutely confident," Volkov told reporters this week. "We hope that everything is going to be normal and we'll land in a normal way, not a ballistic reentry."

• Click here for live NASA video feed of the entire process.

• Click here for more photos.

• Click here to visit FOXNews.com's Space Center.

The last two Soyuz vehicles to return to Earth — in April and October 2007 — landed in a backup ballistic mode, which touched down off-target and subjected their three-astronaut crews to higher than normal G-forces, after a separation failure prevented the three-segment spacecraft from separating properly.

After months of scrutiny, Russian engineers believe a failed explosive bolt to be the cause.

In July, Volkov and Kononenko removed the suspect bolt from their own TMA-12 spacecraft during a spacewalk.

Russian engineers have also come up with new software to keep the Soyuz on target during tonight's landing as it reenters the Earth's atmosphere, Volkov said Monday.

Garriott, too, said he has full confidence in the Soyuz spacecraft and is fully prepared for the extra stress on his body if tonight's landing does return under the ballistic, backup mode.

"I have no concerns about reentry ... I'm excited about the trip home regardless," Garriott told reporters, adding that he has simulated the extra gravitational loads — which can reach more than eight times Earth's gravity — in a centrifuge on Earth. "I think that even if we were to have a ballistic reentry, it's something of course I'll tolerate well, but it also doesn't alarm me in any way."

Garriott is paying $30 million for his 10-day flight to the space station under a deal between Russia's Federal Space Agency and the Vienna, Va.-based firm Space Adventures.

He launched to the station on Oct. 12 with Expedition 18 commander Michael Fincke and flight engineer Yury Lonchakov, who are replacing Volkov and Kononenko as the cosmonauts complete their own six-month Expedition 17 mission.

"It's kind of sad to see our guys leaving the space station, but it's time for them to go home," Lonchakov said on Wednesday. "I wish you a successful landing and we'll see you back on Earth."

Fincke and Lonchakov joined the third member of their crew, NASA astronaut Greg Chamitoff, already aboard the station. Chamitoff joined the station's Expedition 17 crew and will stay on for the first stage of Expedition 18 until his relief arrives with NASA's shuttle Endeavour next month.

Garriott is completing his own private spaceflight, which he packed with science experiments, educational events and Earth observation, while setting some time aside for zero gravity painting.

An Austin, Texas-based computer game developer, Garriott created the successful Ultima Online computer game series and is the sixth paying visitor to the International Space Station.

Garriott is also the son of former NASA astronaut Owen Garriott, who flew aboard the U.S. Skylab space station and shuttle Columbia in the 1970s and 1980s, and plans to greet his son at the landing site. The younger Garriott is the first second-generation American spaceflyer.

By coincidence, the younger Garriott is also flying with a Russian spaceflight legacy.

Volkov is the son of famed Russian cosmonaut Alexander Volkov, and made history during his April launch when he became the first second-generation cosmonaut to reach space.

On Wednesday, Volkov handed control over to Fincke and his Expedition 18 crew and wished his fellow space travelers well as they work to install new equipment over the next few months that will set the stage for larger crews.

"These guys have a lot of difficult tasks ahead of them and I want to wish them success," Volkov said.

Richard Garriott is chronicling his spaceflight training and mission at his personal Web site: www.richardinspace.com.

Copyright © 2008 Imaginova Corp. All Rights Reserved. This material may not be published, broadcast, rewritten or redistributed.