Mission specialists Karen Nyberg and Akihiko Hoshide have conducted a leak check on the newly installed Japanese laboratory Kibo. After that they opened the hatch at 5:05 p.m.

Shortly after entering Kibo, the crew members sampled the air and tested for contamination. They wore protective goggles and masks until they were sure the Japanese lab’s air was clean.

Meanwhile, Mike Fossum and Ron Garan are getting ready for their second spacwalk,

They will start the mission by installing on the Kibo laboratory two cameras that will be used to judge clearances for the module’s robotic arm.

Garan will install the forward camera, while Fossum will work on the aft. They will then work together to remove the seven thermal covers on each of the robotic arms’ six joints and its end effecter.

Each cover will require the spacewalkers to remove two fasteners and disconnect two grounding wires. Next, they will prepare the laboratory’s top active common berthing mechanism for the attachment of a smaller section of the module, the JLP, which was delivered during STS-123. To do so, they’ll remove the berthing mechanism’s thermal cover, the bolts securing two micrometeoroid orbital debris shields and a launch lock, and inspect its surface.

They’ll also install thermal covers on the metal post that connected the laboratory to the shuttle’s cargo bay. After that, Garan and Fossum will split up to prepare for a nitrogen tank assembly swap that they’ll perform on the mission’s third spacewalk.

The nitrogen tank assembly uses high-pressure nitrogen gas to control the flow of ammonia out of the ammonia tank assembly. Ammonia is used to control the temperature on the station’s exterior. Fossum will move to the left side of the station’s truss, where a spare nitrogen tank assembly will be located on External Stowage Platform 3.

He will install an articulating portable foot restraint onto the platform for use during the next spacewalk, and loosen the four bolts that anchor the nitrogen tank assembly to the platform. And to prevent overheating during the swap, he will install thermal covers over the assembly’s quick disconnect lines.

Garan also will loosen the bolts and install thermal covers on the old nitrogen tank assembly, which is on the starboard truss. In addition, he will disconnect three electrical connections and the nitrogen lines that attach the assembly to its corresponding ammonia tank assembly. For the final tasks of the spacewalk, Garan will join Fossum on the left truss to remove an external television camera that has a failing power supply. They will bring the camera inside with them, where the power supply will be replaced, and then reinstall it during the third spacewalk.