The space shuttle Endeavour has undocked from the International Space Station (ISS) on Friday and it is headed home, to the Kennedy Space Center. After running some tests of the critical landing systems, the shuttle and its seven astronauts are scheduled to touch down at 1:19 p.m. Sunday, if the weather permits.

Endeavour and its crew helped ISS turn into a station that can host 6 people now, in quite a luxury. The station’s “makeover” included delivery of a new refrigerator, toilet, sleep stations, exercise machine and a system to recycle astronauts’ urine and sweat into drinking water. All of these are necessary for crews on the orbiting lab to double to six people next year, a vital expansion that aims to ramp up science research.

Endeavour spent almost 12 flight days docked with the station, falling just shy of a record Endeavour set earlier this year. The shuttle was maneuvered from the station by pilot Eric Boe just before 10 a.m. Friday. Boe guided the shuttle’s nose cap and wing edges, looking for damage space debris could have caused. It’s very important to analyze that, because those reinforced carbon surfaces will be subjected to temperatures reaching 3,000 degrees during re-entry into Earth’s atmosphere. Mike Sarafin, a NASA flight director, told the media: “Now it’s just a matter of getting Endeavour home.”

As for the spacewalks, astronauts Heidemarie Stefanyshyn-Piper, Stephen Bowen and Shane Kimbrough took turns cleaning and lubricating a rotary joint, replacing metal bearings. They also did some preventive maintenance on the station’s second joint. This way, NASA avoided an expensive modification or replacement of the degraded joint. NASA has eight more flights scheduled to the space station and a final servicing call to the Hubble Space Telescope before the shuttles are retired in 2010.