Astronauts Gear Up for Space Construction Marathon

Seven astronauts are gearing up for what they expect to be a grueling orbital construction mission to the International Space Station this week aboard the shuttle Endeavour.

Veteran shuttle commander Mark Polansky and six crewmates will blast off aboard Endeavour early Saturday on an ambitious mission to complete the space station?s massive Japanese Kibo laboratory. Liftoff is set for 7:17 a.m. EDT (1117 GMT) from NASA?s seaside spaceport in Cape Canaveral, Fla.

Endeavour is poised to fly a marathon 16-day flight packed with five spacewalks and complicated robotic arm work to install a porch-like external experiment platform, spare space station parts and perform maintenance work.

?It?s complex, it?s challenging, it?s long,? Polansky said of the mission. ?It?s going to be a really complicated choreography.?

As planned, the mission will tie the record for longest shuttle flight to the station. It will also mark the first time 13 people have lived aboard the outpost at the same time since the station doubled its population to full six-person crew earlier this month.

Here is a look at Endeavour?s six-man, one-woman crew for the upcoming STS-127 mission to the space station:

Veteran in command

Leading Endeavour?s crew is Polansky, 53, a two-time shuttle flyer making his third trip to the space station. But the mission is Polansky?s first foray into the online micro-blogging Web site Twitter, where he has been detailing the mission under the handle @Astro_127.

?I really want people in every walk of life to understand that NASA exists,? said Polansky, who has more than 17,800 followers and is the second NASA astronaut to use the social networking tool on a mission.?

A veteran U.S. Air Force test pilot from Edison, N.J., Polansky joined NASA?s astronaut corps in 1996 and is making his second trip as commander. He is married to wife Lisa and has a 4-year-old daughter and a young son who will turn 2 years old during the upcoming spaceflight.

During Endeavour?s flight, Polansky will keep close tabs on his crew to make sure everyone rests between spacewalks and challenging robotic operations.

?You also get a little chronic fatigue. It?s easy to go ahead and not realize how tired you are,? Polansky said. ?I?ll be the mother hen and watch over things like that.?

Pilot?s view on risk

Endeavour?s pilot is U.S. Marine Corps Lt. Col. Doug Hurley, 42, who will begin the first spaceflight of his astronaut career when the shuttle blasts off.

A test pilot from Apalachin, N.Y., Hurley joined NASA?s astronaut ranks in 2000 and has a unique view on the risks of human spaceflight. He was the last person to see the seven astronauts of the shuttle Columbia?s STS-107 mission before they launched into space on their ill-fated 2003 flight that ended tragedy during re-entry.

?Being the last person to see them in person, it took a while for me to work through that and what I was doing? it?s a tough deal to lose seven friends in an instant,? Hurley told SPACE.com. ?Spaceflight?s not routine, there?s significant risk. But there?s also significant reward and I?m comfortable with the risk.?

Hurley said he?s looking forward to looking out Endeavour?s windows at Earth and he apparently likes to go fast. His NASA biography lists watching ?as many NASCAR races as possible? as one of his chief interests

?I don?t know what it was, if it was the cars or just the spectacle,? Hurley said of the first time he went to a race. ?But I was immediately hooked.?

Astronaut 500

Rookie astronaut Chris Cassidy, a veteran U.S. Navy SEAL, will be pulling double duty during Endeavour?s flight. Not only is the Navy commander part of the shuttle?s four-man spacewalking team, he is also slated to become the 500th person in history to reach space once the shuttle launches.

?I?m honored to have a position, whether it?s 499, 500 or 501,? Cassidy, 39, said in an interview. But he and his crew have been training so hard, they were unaware of the space history milestone, he added.

Cassidy grew up in York, Maine, and spent 10 years as a Navy SEAL. He joined NASA?s astronaut corps in 2004, on his second try, as part of the agency?s most recent class. He will serve as Mission Specialist 1 and perform three spacewalks during the upcoming mission.

?That whole first 8 1/2 minutes, I just can?t wait,? Cassidy said of the initial launch into space. He and wife Julie have three children, two daughters - ages 14 and 11 - and a 10-year-old son. His younger daughter will turn 12 the day before launch, Cassidy said. ?

Canadian?s return to orbit

Canadian Space Agency astronaut Julie Payette, 45, is the only non-American on Endeavour?s crew and the mission?s robotic arm expert, which is fitting since the main robotic arms on both the shuttle and the International Space Station were built by her home country. She first flew in space during a 1999 NASA shuttle mission and is eager to see how she?ll react in orbit again.

?It?s been 10 years since I?ve been in space,? Payette said in a recent briefing. ?I really wonder if my brain will remember what it?s like to return to weightlessness.?

As Mission Specialist 2, Payette will oversee some of the most challenging robotic arm operations, which include seven different handoffs of massive components between from one arm to another. She will also serve as the mission?s flight engineer to aid Endeavour?s commander and pilot during launch and landing.

A native of Montreal, Quebec, Payette is married to husband Billie Flynn and has two sons, ages 15 and 4, though her youngest will turn 5 during the spaceflight.

She joined Canada?s astronaut corps in 1992 and will join another Canadian astronaut, Robert Thirsk, in space after launching. Thirsk is part of the station?s six-man crew. It will be first time two Canadians have been in space at the same time, with a third Canadian citizen - space tourist Guy Laliberte - slated to launch later this year.

?It does touch people and it is part of their lives,? Payette said of Canada?s space efforts. She plans to take some traditional cookies shaped like maple leafs and other national treats to mark the mission, she added.

Astronaut doctor

After years helping others cope with the medical effects of spaceflight, Endeavour astronaut Tom Marshburn is eager to experience them for himself.

?I?ve followed people flying in space for 15 years now, and to be able to experience some of those things ? I just can?t wait to try it out and see how it works,? Marshburn, 48, told SPACE.com.

A former emergency room doctor and NASA flight surgeon, Marshburn is Endeavour?s Mission Specialist 3 and will perform three spacewalks during the flight. In addition to his medical degree, Marshburn holds degrees in physics and engineering physics and hoped from a young age to find a place at NASA.

?It was a little bit late in high school, and I thought, ?Boy, I?d love to work for NASA. I?d love to build rockets.? That?s what I wanted to do, build spaceships,? Marshburn has said. ?I never thought I could be an astronaut actually but I wanted to work for NASA.?

Marshburn grew up in Statesville, N.C., and once backpacked from Canada to Mexico along the Pacific Crest Trail. He joined NASA as a flight surgeon in 1994 and was selected to be an astronaut in 2004. Marshburn is married to wife Ann and has a 6-year-daughter.

The spacewalk guru

The undisputed veteran of Endeavour?s crew is also the shuttle?s spacewalking chief - astronaut Dave Wolf - who will make his fourth trek in to space during the upcoming flight. In addition to two shuttle flights, Wolf also spent 128 days living aboard Russia?s former Space Station Mir.

?I really feel like I?m going home to space,? Wolf, 52, told reporters recently.

A veteran of four spacewalks, Wolf will serve as Mission Specialist 4 and the lead spacewalker during Endeavour?s tricky construction flight. He will perform three spacewalks himself and choreograph the others after years of serving as chief of the spacewalking branch at NASA?s Astronaut Office.

Wolf is from Indianapolis, Ind., and joined NASA?s astronaut corps in 1990. He is a medical doctor and engineer, as well as a retired Air National Guardsman with a passion for acrobatic flying (he rebuilt his own plane) and recently built a motorcycle from scratch.

A penchant for tinkering is vital for astronauts tackling the ?wall of spacewalks,? more than 120 so far, to build the space station over more than 10 years, Wolf said.

?The wall was really hard, but in fact we made it?we got over it,? said Wolf. ?We have a lot of [spacewalking work] yet to go, we just know how to deal with it better.?

Space station or bust

Rounding out Endeavour?s crew is U.S. Army Col. Tim Kopra, a 45-year-old test pilot making his first trip into space. While Kopra will begin Endeavour?s Mission Specialist 5, his true home is the station, where he plans to spend months living and working in space.

?I?m just really excited about it,? Kopra said in an interview, adding that being an astronaut was on his childhood short list of lifetime goals. ?I really couldn?t be happier.?

Kopra grew up in Austin, Texas, and has two children - a daughter, 13, and son, 12, - with his wife Dawn. He joined NASA?s astronaut corps in 2000 and will perform one spacewalk while Endeavour is docked at the station.

As a NASA flight engineer, Kopra will replace Japanese astronaut Koichi Wakata as part of the station?s first full six-person crew. Wakata is Japan?s first long-term space resident and has lived aboard the station since March. He will return to Earth aboard Endeavour while Kopra will ride another shuttle home in August.

?It?ll be a little more of a personal place to work because there?s more interaction with people,? Kopra said of the larger staffed station. ?We have a lot of space, but it needs to be carefully choreographed so that it works out.?

SPACE.com will provide complete coverage of Endeavour?s STS-127 mission to the International Space Station with Staff Writer Clara Moskowitz and Senior Editor Tariq Malik in New York. Click here for mission updates and a link to NASA TV.

• Video - Emergency Drill: Danger on the Launch Pad
• Image Gallery - Shuttle Endeavour Blasts Off at Night
• Video Show - The ISS: Foothold on Forever