The fourth Progress vehicle dedicated to station resupply is set to launch atop a Soyuz rocket at 5:33 p.m. Sunday from the Baikonur Cosmodrome in Kazakhstan. Docking to the back end of the Zvezda module is scheduled at approximately 7:20 p.m. next Tuesday. Commander Yury Usachev has checked out the station's manual docking system in the event the automatic docking procedure does not work.
While awaiting the arrival of the Progress carrying 3,100 pounds of supplies, including food, spare computer parts, and other logistical items, crewmembers Jim Voss and Susan Helms are preparing to continue the on-orbit checkout of the station's new robotic arm that will be used to install the station's airlock next month.
On the heels of last week's test of the robotic arm, known as Canadarm2, the station's remote manipulator system will be tested beginning about 5:30 Central Thursday morning.
Setting the stage for that test was the reconfiguration of the operational string of software from Prime to Redundant. This will allow a full checkout of the arm using this backup system in the event that the primary channels were to fail. The arm will be maneuvered through various positions, its end effector snares will be cycled and the video cameras will be checked.
Next Thursday, May 24, Helms will maneuver the arm through the exact movements as if the airlock was attached. This will serve as a "dry run" for what is planned during the removal from the shuttle's payload bay and the installation on the Unity module. The first set of testing a week ago verified the arm's functions in the primary mode culminating in the capture of a grapple fixture on the outside of Destiny. All of the arm operations are controlled via the station's command and control computers, which have been restored to full functionality.
The robotic arm checkout is scheduled every Thursday for the next five weeks to ensure it is healthy before Atlantis launches carrying the airlock.
Last Friday, the third C&C computer was swapped with a spare that was built out of existing computer components on board. It has since been loaded with software identical to the other two C&C computers. Working in the same area behind a rack in the laboratory, a blocked filter in a condensate dump line was changed allowing full operation of the water dump system. This repair precludes the need to transfer wastewater to 100-pound containers for disposal aboard the shuttle when it visits.
The failed hard drive was returned aboard Endeavour after the 6A mission and troubleshooting continues as to the cause of that failure in late April.
Presently, both U.S. solar arrays delivered on assembly flight 4A last November are locked in place while engineers evaluate higher than normal electrical currents on the motors that allow the arrays to track the Sun. The arrays continue to absorb plenty of solar energy to provide the required electrical power for station experiments, avionics and other components on board.
Science investigations continue onboard under the auspices of the Payload Operations Center at NASA's Marshall Space Flight Center in Huntsville, AL, except for the Human Research Facility, which is monitored and controlled from the Telescience Support Center (TSC) at the Johnson Space Center, Houston.
The International Space Station is operating in excellent shape at an altitude of 250 miles (401 km).