The US space shuttle Endeavour on Sunday prepared to undock from the International Space Station and jet back to Earth, wrapping up its final journey before entering retirement, NASA said. Endeavour's last mission is the penultimate flight for the 30-year US shuttle program, which will end for good after the Atlantis mission to the orbiting research lab in July. The six-member crew of the Endeavour bid farewell to three astronaut colleagues on board the space station and closed the hatches between the shuttle and station at 7:23 am (1123 GMT), NASA said. The astronauts were to spend the day finishing up some final checks and then were to get some sleep in preparation for the late night separation maneuver. "Endeavour's crew now will prepare for undocking at 11:55 pm (0355 GMT) by completing a check out of the rendezvous tools and installing the centerline camera before concluding their flight day at 11:26 am (1526 GMT)," NASA said. Endeavour's 16-day mission began with the shuttle's launch from Cape Canaveral, Florida on May 16 and will conclude when the shuttle lands back on Earth early on June 1. The team spent a total of 10 days, 23 hours, and 45 minutes at the space station. During that time, the crew delivered and installed a massive physics experiment, the Alpha-Magnetic Spectrometer-2, that will be left at the space station to scour the universe for clues about dark matter and antimatter. They also brought up a logistics carrier with spare parts for the orbiting lab and performed some maintenance and installation work during four spacewalks, the last to be done by an American shuttle crew. Endeavour is scheduled to land at Kennedy Space Center at 2:35 am (0635 GMT) on June 1.