Heide Stefanyshyn-Piper and Shane Kimbrough will camp out overnight in the station’s Quest Airlock in preparation for the second spacewalk of the mission.

Expedition 18 flight engineer Sandra Magnus and her predecessor Greg Chamitoff installed two new bedrooms in the Harmony node. Meanwhile, STS-126 mission specialist Don Pettit and Expedition 18 commander Mike Fincke spent the bulk of the day configuring hardware on the new Water Recovery System.

Meanwhile, in an interview for AP, Heide Stefanyshyn-Piper admitted she made a mistake during the previous spacewalk.

During the first spacewalk of the mission, she was trying to clean up grease that had oozed out of a grease gun in the backpack-size bag, when the tote and everything in it floated away.

"You're not going to see us lose another bag. We're going to double- and triple-check everything from here on out," she said.

During the second spacewalk, Piper and Kimbrough will relocate the two Crew and Equipment Translation Aid (CETA) carts from the starboard side of the Mobile Transporter to the port side, lubricate the station robotic arm’s latching end effector A snare bearings and will continue cleaning and lubrication for the starboard SARJ and replacement of its 12 trundle bearing assemblies.

The first task of the second spacewalk will give Kimbrough a chance to ride the station’s robotic arm. He and Piper will move the station’s two Crew and Equipment and Translation Aid, or CETA, carts, the rail carts that allow astronauts to move equipment along the station’s truss, from their current homes on the starboard side of the station’s Mobile Transporter (MT) to the port side.

Piper will get the carts ready for transfer by moving them into position and unlocking their wheel bogies. Kimbrough first will carry CETA 1 and then CETA 2 as he is flown on the robotic arm from one side of the MT to the other. Piper will meet him there each time, to install the carts in their new locations. When that task is done, Kimbrough will climb off of the robotic arm and remove the foot restraint Piper installed on the first spacewalk.

This will give him access to the arm’s latching end effector, or LEE, the snares that allow it to grasp equipment. Inside the station, Pettit and Magnus will command the LEE, which has been experiencing some sticky spots, to open and close its snares. Kimbrough will apply lubricant to the LEE’s snare bearings and rotate the bearings using needlenose pliers to ensure the lubricant covers the bearings. Meanwhile, Piper will return to the starboard SARJ to continue its cleaning and lubrication.