In this Thursday, March 3, 2011 photo provided by NASA, astronauts Scott Kelly, left, Expedition 26 commander; Cady Coleman, center, Expedition 26 flight engineer; and Michael Barratt, STS-133 mission specialist, watch a monitor in the Unity node of the International Space Station while space shuttle Discovery remains docked with the station. (AP Photo/NASA)

(AP) -- The astronauts aboard the orbiting shuttle-station complex will share a few more maintenance chores before they part company.

On Saturday, the two crews will work on the air system at the . They also will make sure a Japanese cargo carrier is properly loaded with trash. It will be let loose at the end of this month and plunge through the . The vessel is full of packing foam from all the equipment that was delivered by Discovery.

The shuttle arrived last Saturday.

The hatches between the two craft will close Sunday afternoon. And the shuttle will undock first thing Monday.

It's the last voyage for Discovery. It will be retired following Wednesday's touchdown and put in a museum.