Step by step, piece by piece, a whole new world has been taking shape above the Earth. It is floating independently in space, and makes history every time something new is added.

This month the International Space Station marks a major milestone in space exploration, celebrating the 10th anniversary of its first parts being blasted into orbit 220 miles above the Earth.

And this week a mission by the U.S. space shuttle Endeavour is making history by expanding and upgrading the space station in important ways.

The upgrade is so dramatic, America’s NASA space agency is calling it “Extreme Home Makeover” — Outer Space Edition. But this makeover is a lot more impressive than the ones on the popular TV show.

The Endeavour mission, which is scheduled to end November 29, is changing the space station home for astronauts and scientists from a three-bedroom with one kitchen and one bath into a five-bedroom with two kitchens and two baths.

The makeover also is adding much needed exercise equipment for the crew and installing a high-tech water recycling system that can purify the crew’s sweat and urine into clean, drinkable water.

Once 15,000 pounds of new gear and equipment have been installed, six astronauts and scientists will be able to live and work on the station, instead of the three that live there today.

Building the International Space Station has been the biggest achievement in space cooperation ever.

More than 15 nations are working together in the effort, led by the United States, Russia, Canada and 11 nations of the European Space Agency.

The first two pieces of the space station were joined in the winter of 1998, when a U.S. crew used a Canadian crane to connect a Russian control module to a U.S. docking port.

The first three-person crew came to live there in November 2000. All together, 167 people from 15 countries have visited or worked on the station.

A 10-year anniversary is a great thing to celebrate for any space mission. But space station planners had hoped it would be fully built by now.

The program was set back for months after the U.S. shuttle Columbia was destroyed in an accident, delaying shuttle flights that would have delivered equipment for safety reasons.

Now 85 percent complete, the space station has cost the U.S. an estimated $100 billion so far. It is expected to be finished in 2010, the year the U.S. space shuttle fleet is expected to be shut down.

Still, construction of the space station is one of the biggest engineering feats in history. The station is now the largest space craft ever built at 291 feet and 627,000 pounds.

“The station’s capability and sheer size today are truly amazing,” International Space Station Program Manager Mike Suffredini told the Science Daily Web site this month. “… We have overcome differences in language, geography and engineering philosophies to succeed.”