International Space Station astronauts complete spacewalk

Tuesday, November 20, 2007

Expedition 16 Commander Peggy Whitson (upper left) and Flight Engineer Dan Tani work outside the International Space Station during the 20 November 2007 spacewalk

Two International Space Station astronauts completed a 7 hour and 16 minutes spacewalk this morning that saw the completion of the ISS's newest room, Harmony.

Commander Peggy Whitson and Flight Engineer Daniel Tani began their spacewalk early Tuesday morning at 5:10 a.m. EST (10:10 UTC). This was the second phase of a three phase project to complete the connection of the Harmony module to the rest of the Space Station. Whitson, who is ISS's first female Commander, exclaimed "Yay, got it!" after finishing a particularly difficult section of the hand-intensive project. The goal of the 7+ hour EVA was to complete the connection of the power and heating cables and the fluid lines between the space station and the Harmony laboratory which the Space Shuttle Discovery delivered to the space station last month.

The International Space Station 3 weeks ago before the new room was added

During the dangerous spacewalk, the spacewalkers removed the fluid lines (which carry ammonia in an 18½-foot (5.6 m), 300-pound (136 kg) tray) and removed the tray from its storage location on the space station, then lugged it over to Harmony and bolted it down. The tray, which was awkward to carry, required the astronauts to take turns carrying it over to Harmony being careful not to bang it around. A frightening moment occurred during the venting of the hook ups that saw frozen ammonia crystals floating out and bouncing off of Whitson. NASA Mission Control explained to her that it was nothing to worry about at the time and that decontamination procedures would take place later. These decon procedures include brushing off the toxic substance and letting the sun bake it off.

The station's three astronauts have been working continuously since the Space Shuttle Discovery departed on the 5 November 2007 to get the new lab attached. The next shuttle mission is scheduled to lift off on 6 December 2007 with a new laboratory that will dock to Harmony, but the shuttle cannot commence its mission until Harmony is completely attached. A third and final Harmony space walk is scheduled for Saturday 24 November 2007 to attach the final fluid tray and complete connections to the Harmony lab.