Feb. 4, 2007

Katherine Trinidad
Headquarters, Washington

John I. Petty
Johnson Space Center, Houston



HOUSTON - For the second time in four days, two residents of the
International Space Station stepped outside for a spacewalk to
complete connecting cooling loops from a temporary to a permanent
system. This time the excursion lasted just over seven hours.

Wearing U.S. spacesuits, Expedition 14 Commander Mike Lopez-Alegria
and Flight Engineer Suni Williams began their spacewalk at 7:38 a.m.
CST, a few minutes ahead of schedule. After setting up tools and
tethers outside the Quest airlock, they moved to the area that
connects the Z1 truss to the S0 truss at the middle of the station’s
large girder-like truss system. This area is known as the “rats’

In these tight quarters, they rerouted a series of two electrical
cables and four fluid quick disconnect lines from the soon-to-be
defunct Early External Active Thermal Control System to a permanent
cooling system in the Destiny Laboratory. The cooling loop
reconfigured Sunday, known as the Moderate Temperature Loop (Loop B),
removes heat from the station’s avionics systems and payload racks
through a heat exchanger system in the Destiny Laboratory. On Jan.
31, Lopez-Alegria and Williams reconfigured a Low Temperature Loop
(Loop A) that rejects heat from the station’s environmental systems.

On Sunday, the spacewalkers also assisted in the retraction of the aft
heat-rejecting radiator on the P6 truss. The radiator had been used
since 2000 to keep station systems at the correct temperature through
the temporary cooling system. They helped tie the radiator down with
a series of cinches. Unlike the starboard radiator, which was
retracted Jan. 31, the aft radiator did not require the installation
of a protective thermal shroud due to the station’s orientation to
the sun. During this summer’s STS-118 shuttle mission, a third
radiator will be retracted, the only radiator on the P6 truss that
will be redeployed after the truss is relocated to the far port side
of the truss.

Once the radiator was retracted, Lopez-Alegria and Williams completed
Wednesday’s unfinished task of disconnecting and stowing the second
of two fluid lines for the Early Ammonia Servicer, a large tank on
the P6 truss that is no longer needed. The EAS was designed to
replenish ammonia to the temporary cooling system on the station in
the event of a coolant leak. The servicer will be jettisoned during a
spacewalk by the Expedition 15 crew this summer.

Lopez-Alegria, at the base of the P6 truss, photographed the starboard
solar array and the blanket box into which it folds. Engineers will
analyze the photos and finalize plans to retract that array during
the STS-117 shuttle mission to the station next month.

After the photographs were taken, Lopez-Alegria and Williams resumed
the stringing of electrical cables from the S0 truss to the Destiny
Laboratory and to its forward docking port, Pressurized Mating
Adapter-2 (PMA-2), to which visiting shuttles dock. The cables
provide electricity for the Station-to-Shuttle Power Transfer System
(SSPTS). The system will enable docked shuttles to draw electrical
power from the station to extend their missions. SSPTS is scheduled
to debut during STS-118, enabling Endeavour to fly for two weeks.
Three of the six cables were connected Sunday. The others probably
will be connected during a spacewalk Thursday, Feb. 8.

Lopez-Alegria removed a sunshade from a data relay box on another
pressurized mating adapter that connects the U.S. and Russian
segments of the station. Since the shade is no longer needed, it was
folded up and brought inside to be discarded either on a future
Russian Progress cargo ship or a shuttle mission. Back in the
airlock, Lopez-Alegria and Williams did some precautionary
decontamination procedures after a few ammonia flakes were seen early
in the spacewalk.

The spacewalk ended at 2:49 p.m. as the crew returned to Quest. It was
the eighth spacewalk of Lopez-Alegria’s career and the third for
Williams. He surpassed astronaut Steve Smith to vault into third
place on the all-time spacewalking list for most hours spent outside.
Williams now holds the record for most spacewalking time by a female.
Former astronaut Kathy Thornton previously held that honor. Sunday’s
spacewalk was the 79th for station assembly and maintenance and the
51st done without a shuttle present.

On Monday, Lopez-Alegria and Williams will recharge batteries and
prepare their spacesuits and tools for the next spacewalk set for
Thursday morning.

For more about the crew’s activities and station sighting
opportunities, visit: