Once they swap out their custom-made Soyuz capsule seat liners with those belonging to Expedition Two Commander Yury Usachev and Flight Engineers Jim Voss and Susan Helms, Culbertson, Dezhurov and Tyurin will become the third trio of residents to inhabit the complex, while Usachev, Voss and Helms become members of Discovery's crew.
The Soyuz serves as a crew return vehicle in the unlikely event it should become necessary to leave the station.
Official handover of command of the ISS from Usachev to Culbertson will take place on August 20, shortly before Discovery undocks from the Station.
After the crew transfer is complete, the oncoming ISS residents will begin a comprehensive handover with their departing counterparts, receiving briefings on Station systems, the current configuration of hardware and computers and procedures they will employ during their first days on board the outpost.
Mission Specialist Pat Forrester will use Discovery's robot arm to move the Italian-built Leonardo cargo module from the shuttle's payload bay to the nadir docking port of the Station's Unity module so it can be unloaded of more than three tons of supplies and equipment for the newly arrived Expedition Three crew. Leonardo also contains racks of scientific experiments which will greatly enhance the scientific research on board the ISS over the next few months. Leonardo will be installed on the Station late this morning.
Other equipment will be transferred throughout the day from Discovery's middeck lockers to the ISS as the crews work in concert to set the stage for the Expedition Three mission.
The joined spacecraft are orbiting at an average altitude of about 244 statute miles, completing an orbit of the Earth every 90 minutes. Both craft are in good condition.