Continuing the activation of the S3/S4 and assist in the retraction of the starboard solar array on the Port 6 (P6) truss

Final work to activate the Solar Alpha Rotary Joint (SARJ)

After Canadarm2 released S6 and moved away, the spacewalkers plugged in power and data cables to connect the new hardware and remove launch restraints from the photovoltaic radiator and the boxes containing the new solar arrays. They also deployed the Beta Gimbal Assemblies, which contain the masts that support the solar arrays, and position the boxes for later deployment.

First task during this spacewalk was to prepare a worksite for new batteries that will be brought up on the STS-127 mission. They also installed a Global Positioning System antenna on the pressurized logistics module attached to the Kibo laboratory.

The astronauts replaced a backup multiplexer-demultiplexer (MDM) that failed during routine testing April 11, 2014. The box is one of the station's two external MDMs that provide commands to some of the space station's systems, including the external cooling system, solar alpha rotary joints (SARJ) and mobile transporter rail car.