This story was updated at 2:55 p.m. EDT.
The space shuttle Endeavour cast off from the International Space Station Tuesday after a whirlwind 11 days of construction work at the orbiting laboratory.
Endeavour?s seven astronauts undocked from the station at 1:26 p.m. EDT (1726 GMT), ending a hectic week and a half that delivered a new crewmember, spare parts and a Japanese experiment porch that completed the outpost?s giant Kibo laboratory.
?We?re sad to leave you, but hopefully happy that we?ve left the station in pretty good shape,? Endeavour skipper Mark Polansky told the station?s six-man crew, adding that it was great to be part of the outpost?s first-ever 13-person crew. ?So we wish you all a safe journey for what?s left of your increments, and good luck as we head back home.?
Endeavour launched toward the space station July 15 and arrived two days later to begin a marathon of space construction that included five challenging spacewalks and a host of tricky robotic arm operations. The crown jewel of the orbital work was the installation of Kibo?s new porch, an external platform that can expose experiments to the space environment, and then change them out using the laboratory?s small airlock and robotic arm.
Spacewalking astronauts also gave the space station a new set of solar array batteries and stocked it up on vital spare parts, equipment that is so large only NASA?s space shuttles can deliver them to the outpost.
Endeavour pilot Doug Hurley guided the shuttle in a victory lap around the space station after undocking, with cameras aboard both spacecraft beaming home stunning views of each other and the Earth.
?We?d like to go ahead and bid you farewell, and fair sailing ahead guys,? Polansky radioed the station crew as Endeavour fired its engines to begin the trip home.
Largest space crowd splits up
Endeavour?s arrival at the station was a key test of its systems since it boosted the outpost?s population to 13 people - the highest ever in 10 years of construction. During the mission, a broken space toilet and malfunctioning air-scrubber on the station caused some concern, but both glitches were swiftly repaired within a day of their respective failures.
?You made us bigger and better, and we were really glad to have you here,? station astronaut Michael Barratt of NASA told Endeavour?s crew as the shuttle pulled away. ?It seems awfully quiet here now without you.?
Station commander Gennady Padalka, a Russian cosmonaut, thanked the visiting shuttle astronauts for their hard work. He rang the ship's bell aboard the station in a traditional salute to departing spacecraft and crewmembers.
?So guys, we'll be missing you. Have a safe trip,? Padalka told Endeavour?s crew before the shuttle left. ?We'll be looking forward to seeing you again on the ground, sooner or later."
Padalka said a special goodbye to Japanese astronaut Koichi Wakata, who is returning home aboard Endeavour after living aboard the space station for 4 1/2 months. Wakata, who represents the Japan Aerospace Exploration Agency, is Japan?s first long-term resident of the space station and watched over the country?s $1 billion Kibo laboratory during his stay.
?A special thank you to Koichi-san,? Padalka said. ?As crew commander, I want to say we could rely on him in any situation.?
While Koichi was aboard the station, the five partner space agencies building the $100 billion space station - the United States, Russia, Japan, Canada and Europe - were all represented aboard the orbiting lab. NASA astronaut Tim Kopra, who arrived at the station aboard Endeavour, replaced Wakata as a station flight engineer earlier in the shuttle flight.
On Wednesday, Endeavour astronauts plan to inspect their shuttle?s heat shield for any new damage sustained from space junk or micrometeorites during the spaceflight. NASA engineers have already given the shuttle a clean bill of health with respect to launch debris. Tomorrow?s heat shield survey is a standard chore for shuttle crews since the tragic 2003 Columbia disaster that killed seven astronauts during re-entry. A large chunk of debris punched a hole in the left wing of Columbia during launch, leading to the loss of the spacecraft and its crew.
When the Endeavour lifted off, more foam insulation than usual fell from shuttle?s fuel tank and caused minor damage, but the dings pose no risk to the spacecraft or its astronaut crew, mission managers have said.
Endeavour is due to land in Florida Friday at 10:47 a.m. EDT (1447 GMT) at NASA?s Kennedy Space Center.
- Video - Space Station?s Population Boom
- Video - The Kibo Lab: Japan's Hope in Space - Part 1, Part 2
- SPACE.com Video Show - The ISS: Foothold on Forever
SPACE.com is providing continuous coverage of STS-127 with reporter Clara Moskowitz and senior editor Tariq Malik in New York. Click here for mission updates and SPACE.com's live NASA TV video feed.