Washington - The US space shuttle Discovery began its earthward journey Wednesday after its mission to carry out further construction and maintenance work on the International Space Station (ISS). The shuttle with seven astronauts aboard is scheduled to land on Saturday at the Kennedy Space Centre at Cape Canaveral, Florida, completing its 14-day trip.
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, 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.
US astronaut Garrett Reisman, who lived aboard the ISS since March, is returning to Earth with Discovery. He is being replaced on the ISS crew by US astronaut Greg Chamitoff.
Discovery crew members also delivered parts to repair a malfunctioning toilet on the ISS. Russian cosmonaut Oleg Kononenko took two hours to change the pump in the multi-million dollar, high- tech space toilet.
