The six-member Expedition 40 crew is counting down to a Thursday morning spacewalk. Meanwhile, the orbital residents are conducting an array of international science and station maintenance tasks.

A pair of cosmonauts spent Tuesday morning conducting a dress rehearsal of Thursday's spacewalk. They donned their Russian Orlan space suits, checked their systems and performed a fit check at suit pressure.

Flight Engineers Oleg Artemyev and Alexander Skvortsov will exit the Pirs docking compartment Thursday at 9:50 a.m. EDT for about six hours and 30 minutes of work outside the Russian segment of the station. They will install an antenna and a cargo boom, swab samples from a window on the Zvezda service module and switch out science experiment gear.

After the completion of their spacesuit exercises they installed replaceable spacewalk elements on their suits. The duo also got in their daily workout regimen.

Their crewmate, Max Suraev, assisted the Russian duo during their dry run activities. In the afternoon, Suraev participated in the Matryoshka experiment checking instrumentation that detects radiation inside a phantom containing materials that simulate human tissue.

Commander Steve Swanson worked throughout Tuesday on a variety of science and maintenance tasks. He spent some time charging batteries in tiny student-controlled satellites for an upcoming experiment run of the SPHERES-Slosh investigation. Afterward, he put on his plumbing hat as he filled then depressurized a flush water tank in the Harmony node's bathroom, or the Waste and Hygiene Compartment.

Later, the commander joined NASA astronaut and new Flight Engineer Reid Wiseman for an investigation that observes how a crew member's body measurement changes during long-term exposure to microgravity. Finally, Swanson retrieved dosimeters that measure neutron radiation levels for the Radi-N2 study and powered down the Microgravity Science Glovebox.

Wiseman opened up the Fluids Integrated Rack to prepare samples for the Advanced Colloids Experiment (ACE). He also set up the Light Microscopy Module inside the rack for the ACE study which observes the microscopic behavior of liquids and gases separating from each other.

German astronaut Alexander Gerst, from the European Space Agency, measured his body mass using the Space Linear Acceleration Mass Measurement Device (SLAMMD). The device applies a known force to a crew member with the resulting acceleration used to calculate body mass.

Gerst later replaced cable arm ropes and applied the proper tension on the Advanced Resistive Exercise Device. After that work, he set up a video camera to record his cable troubleshooting efforts for the Burning and Suppression of Solids experiment inside the Microgravity Science Glovebox.