By Irene Klotz
Cape Canaveral, Florida
With this week's launch of the Columbus space laboratory, Europe will make the transition from a part-time tenant to full-time owner of an outpost in orbit.
To oversee integration of Columbus into the International Space Station (ISS), two European Space Agency (Esa) astronauts will fly aboard the space shuttle Atlantis.
The shuttle is due to lift off with the new module in its cargo hold at 1631 EST on Thursday from the Kennedy Space Center in Florida.
Both Hans Schlegel of Germany and France's Leopold Eyharts will be making their second spaceflights, though it has been 14 years since Schlegel's last shuttle mission and a decade since Eyharts spent three weeks aboard Russia's Mir space station.
"It is a great honour for me to be part of this mission," said Eyharts shortly after he and his six crewmates arrived at the Florida spaceport on Monday to prepare for launch. "It has been a long wait."
Eyharts, who will become a member of the live-aboard station crew, is expected to spend two- to three months in orbit preparing Columbus for a wide range of science experiments.
Schlegel will return with the Atlantis crew after a week-long stay at the complex.
"We're looking forward to having visitors," said station commander Peggy Whitson.
The Atlantis astronauts' time at the station will be anything but relaxed. Installing Columbus is a major undertaking that will require three spacewalks, two of which Mr Schlegel will make with Nasa astronaut Rex Walheim.
If time allows, Nasa may add a fourth spacewalk to inspect a malfunctioning rotary joint needed to keep solar power panels facing the sun.
To reduce wear and tear, Nasa has locked the damaged joint in place, reducing the amount of power available for station operations.
Astronaut Leopold Eyharts last visited space a decade ago
The power shortfall will not create any immediate impacts, but the problem needs to be fixed before Japan's multi-part Kibo science laboratory is installed next year.
With its own module to care for in orbit, the problems of the space station will become Europe's problems as well.
"It's going to be like a mirror of our international co-operation on Earth," Hans Schlegel said in an interview.
"I think the International Space Station is a role model for how, in the future, we as humankind have to tackle our big problems and solve them: only in co-operation, and taking advantage of the capabilities of other nations, of other peoples, of other cultures."
Europe spent more than a decade and more than $1.5bn to join the station partnership.
"Columbus will stay our property," said Mr Schlegel, "our flight control centre will control Columbus. We have the right to do experiments around the clock. When we have a new idea, we can bring it up and (research) it in our own lab," he said.
To pay the United States for flying Columbus, five of the module's 10 experiment racks will be reserved for Nasa's use.
Europe plans to pay its share of operational expenses by flying its newly developed cargo vessels, called the Automated Transfer Vehicle, to the station. The ATV's debut is expected early next year.
"This will be a tremendous step," Schlegel said. "We are becoming a more important partner for the international spaceflight community."