Shuttle Astronauts in Homestretch of Space Mission

Space shuttle Discovery astronauts entered the homestretch of their busy flight to the International Space Station Sunday and are packing up for their trip home later this week.

The shuttle?s seven-astronaut crew planned to finish loading a portable cargo module with tons of trash and unneeded station equipment for the trip back to Earth. The astronauts launched into orbit Aug. 28 and wrapped up the last of three spacewalks to upgrade the space station late Saturday.  

?We?re coming into the homestretch,? space station flight director Heather Rarick told reporters early Sunday.

There are 13 astronauts - a record-tying number - aboard the linked shuttle and station. In addition to Discovery?s seven astronauts, there are six spaceflyers on the station: two Americans, two Russians and one astronaut each from Canada and Belgium.

One tricky task on the astronauts? to-do list Sunday is a robotic arm maneuver to prepare the station for the arrival of Japan?s first unmanned cargo ship later this month. The station?s Canadian-built Canadarm2 robotic arm has a grapple device at each end that allows it to move end-over-end like an inchworm to reach different parts of the station.

Japan?s new cargo ship is designed to be grabbed by the station?s arm when it arrives at the outpost, but one of the robotic appendage?s grapple devices is a bit sticky, Rarick said. Astronauts planned to perform a so-called ?triple walk-off? to move the arm several times so that its non-sticky grapple end is outstretched to await the Japanese space freighter, she added.

Discovery?s crew delivered just over 18,500 pounds (8,391 kg) of cargo to the space station, including fresh supplies, new science equipment and a space treadmill named after television comedian Stephen Colbert. The astronauts will be returning more than 5,000 pounds (2,267 kg) of unneeded items to Earth when they leave the station, NASA officials have said.

The shuttle also ferried NASA astronaut Nicole Stott to the station to begin a three-month space mission. She replaced fellow spaceflyer Tim Kopra as a member of the station?s crew. Kopra has lived aboard the station for nearly two months and will return home aboard Discovery.

Kopra told reporters Sunday that he?s going to miss the space station, but is ready to come home. Discovery is due to undock from the space station on Tuesday and land in Florida Thursday evening.

?I?m very much looking forward to seeing my family and getting back to life in general on the planet,? Kopra said in a televised interview.

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SPACE.com is providing complete coverage of Discovery's STS-128 mission to the International Space Station with Managing Editor Tariq Malik and Staff Writer Clara Moskowitz in New York. Click here for shuttle mission updates and a link to NASA TV.