14 DAY TRIAL // The third and last spacewalk related to the connection of the International Space Station Module Harmony has been completed on Saturday, thus making the European module fully operational and ready to receive the Columbus module which will be flown by the space shuttle Atlantis next month.
The Harmony module serves as a bridge between the International Space Station and the Columbus module, so the connection of the electrical and fluid links was critical for the schedule. Commander Peggy Whitson and Daniel Tani went for the last time outside the station to finish the connections. The module, designed with four docking points, will also accommodate a Japanese laboratory, which will be delivered early next year.
NASA's flight controllers also run several tests on Saturday to check that the cooling and the power systems are operational, so the module will be ready to welcome the Columbus module, which is scheduled to launch on 6th of December.
The spacewalk procedure was somehow similar to the last one and involved carrying a 300-pound tray containing the fluid lines, that will circulate the ammonia coolant, from the space station to the newly installed module.
In the final phase of the spacewalk, commander Daniel Tani inspected again the damaged rotary joint which turns one of the solar panel, needed to provide the station with electrical power, in the hope that the gear will be repaired or replaced, during the mission in which Atlantis would deliver the new laboratory. The rotary joint experienced power spikes and vibration, regardless of the fact that it was installed only four months before the mission of the Discovery space shuttle. On closer inspection, the crew aboard the ISS discovered metal shavings inside the gear, suggesting metal-to-metal grinding or a sever mechanical failure. The mechanism must be fixed before the arrival of the Japanese module, otherwise the space station could experience power shortages.
As the flight controllers on Earth suggested, Tani took digital photos of the rotary joint's mechanism and described the type of debris and the damage he observed. The space station commander reported that the debris was mostly originating from one point, however everything else was covered with a fine dust.
Since the departure of the Discovery space shuttle, the crew on board the ISS has been on a tight schedule, working almost non-stop, to prepare for the arrival of the Atlantis, regardless of the Thanksgiving. During most of the mission outside the station, the crewmate Russian Yuri Malenchenko remained on board the ISS.