Washington - The shuttle Discovery landed back on Earth Saturday at the end of a 14-day mission to install crucial additions to a new space laboratory built by the Japanese space authority. Discovery, whose crew delivered parts to fix a Russian space toilet aboard the International Space Station (ISS), landed at 1515 GMT at Cape Canaveral, Florida, NASA officials said.
After this mission, only 10 more remain for NASA's ageing space shuttles, which are to be retired in 2010. The next mission is slated for October 8 to service the orbiting Hubble space telescope.
The landing schedule appeared to have hit a glitch on Friday with the revelation that a small part had broken off the spacecraft, but NASA concluded that it did not pose any safety concerns.
The small, rectangular object floating away from the shuttle, spotted by a crew member, was apparently a metal clip used to protect the rudder's speed brake during take-off and its loss would not affect landing, NASA said.
Discovery was carrying seven astronauts, including American Garret Reisman, who spent three months aboard the ISS. It left US astronaut Greg Chamitoff behind as the third member of the revolving space station crew.
Discovery undocked from the ISS for the return journey Wednesday after astronauts carried out three spacewalks chiefly devoted to installing and preparing the Japanese scientific laboratory module Kibo.
About 100 scientific experiments are already planned for the 12- metre by 5-metre Kibo, which means "hope" in Japanese, including efforts to examine the effects of weightlessness and help develop allergy medications.
Kibo is to be completed in a third mission later this year.
The toilet onboard the ISS malfunctioned in the week or so before Discovery took off on May 31 with spare Russian parts. Russian cosmonaut Oleg Kononenko took two hours to change the pump in the multi-million dollar, high-tech space toilet.
