The six-person Expedition 40 crew of the orbiting International Space Station spent Wednesday conducting medical research, gearing up for a Russian spacewalk and preparing the station's robotic crew member for a mobility upgrade. The crew also stowed spacewalk tools and equipment following the postponement of two additional spacewalks that were planned for later in August.

International Space Station program managers decided Tuesday to postpone the U.S. spacewalks planned for Aug. 21 and 29 until the fall to allow new Long Life Batteries to be delivered to the station aboard the SpaceX-4 commercial resupply services flight.

A potential issue with a fuse within the battery of the U.S. spacesuits prompted the decision. The delay in completing the proposed spacewalks does not affect any daily operational capabilities of the station.

Following the crew's daily planning conference with the flight control teams around the globe, Commander Steve Swanson began the day with some routine maintenance on the Waste and Hygiene Compartment - the station's toilet located in the Tranquility node.

Afterward, the commander participated in more Ocular Health exams as flight surgeons track the vision health of the astronauts aboard the station. NASA recently identified that some astronauts experience changes in their vision, which might be related to effects of microgravity on the cardiovascular system as the body's fluids tend to move toward the upper body and head and cause the pressure in the skull to rise.

After Flight Engineer Reid Wiseman assisted Swanson with blood pressure measurements, the commander tested his vision with an eye chart. Flight Engineer Alexander Gerst then checked the pressure in Swanson's eyes with a tonometer.

Swanson then went to work in the Quest airlock stowing the spacewalk tools that had been configured for the now-postponed U.S. spacewalks. He also removed batteries from the spacesuits and moved another spacesuit into position so that the crew can remove and replace its fan pump separator next week.

Wiseman, who assisted Swanson with some of the activities in Quest, took a brief break to talk with elementary school students in Japan via the station's amateur radio.

Gerst meanwhile unpacked cargo that arrived at the station aboard the ISS Progress 56 resupply ship on July 23. He also packed trash and unneeded items into Orbital Sciences' Cygnus cargo craft berthed at the station's Harmony node. Cygnus, which arrived on July 16 with nearly 3,300 pounds of science and supplies, will be detached from Harmony by the station's Canadarm2 robotic arm on Aug. 15 and released by the crew for a destructive re-entry over the Pacific Ocean.

On the Russian side of the station, Flight Engineers Alexander Skvortsov and Oleg Artemyev focused on preparations for their spacewalk set for Aug. 18. The two cosmonauts started the workday preparing the replaceable components of the Orlan spacesuits they will wear during their spacewalk.

They also configured the Pirs docking compartment airlock and gathered spacewalking tools. During the excursion, the two cosmonauts will exit through Pirs to deploy a nanosatellite, install two experiment packages and retrieve three others.

Max Suraev, flight engineer and future station commander, began the day refilling the tank for the Elektron oxygen-generating system and performing routine maintenance on the life support system in the Zvezda service module. Later he downloaded micro-accelerometer data from the Identification experiment, which measures dynamic loads on the station during events such as dockings and reboosts.

After a break for lunch, Swanson gathered the tools he will use to perform some work Thursday and Friday on the station's humanoid robot, Robonaut 2. Swanson will be installing a new processor board and other hardware to prepare Robonaut for the installation of its legs.

Since Expedition 25, Robonaut has been put through a series of increasingly complex tasks to test the feasibility of a humanoid robot taking over routine and mundane chores from the human crew members, freeing up their time for more important work. After gathering the tools, Swanson set up Robonaut on its stanchion post in the Destiny laboratory.

Wiseman focused his attention on reviewing procedures for the spacesuit fan pump separator swap slated for next week and also initiated an autocycle of the spacesuit batteries to prepare them for storage.

Wiseman, a Baltimore native, rounded out his day talking with reporters from WYPR Maryland Public Radio and Maryland Public Television.

Gerst meanwhile recorded an educational video for the Story Time project, which seeks to deliver station research content to communities that have not previously been engaged in the space program. Afterward, Gerst performed some maintenance on the Waste and Hygiene Compartment and replaced some audio hardware in the Harmony node.

The European Space Agency's fifth and final Automated Transfer Vehicle (ATV-5), loaded with more than seven tons of scientific experiments, food and other supplies, remains on track for its automated docking to the aft port of Zvezda at 9:30 a.m., Aug. 12.

Nicknamed the "Georges Lemaitre" in honor of the Belgian physicist and astronomer who first proposed the Big Bang theory, the ATV-5 will perform additional course correction maneuvers Thursday. The "Georges Lemaitre" is scheduled to fly directly under the station Friday at a distance of 3.7 miles in a test of sensors and radar systems designed to provide data for European engineers' design of future spacecraft.

After Friday's "fly-under" of the station at 6:45 p.m., the ATV will move in front of the station and transition above and then behind the station for the final four days of its two-week rendezvous. ATV-5 launched atop an Ariane 5 rocket from Kourou, French Guiana, on July 29.