Spacewalkers Rick Mastracchio and Mike Hopkins completed a second
spacewalk to install a spare ammonia pump module. The U.S. Quest airlock
began repressurization at 2:23 p.m. EDT Tuesday signaling the official
end of their spacewalk.
Tuesday’s main tasks included the removal and installation of a spare
pump module. The first task was to remove the spare pump module from
the space station’s External Stowage Platform-3. After that was
completed, the module was bolted to the S1 truss and connected to Loop A
of the station’s external Active Thermal Control System.
Hopkins attached himself to the Canadarm2 and took a ride to the
worksite. Mastracchio tethered himself to the station and translated to
the S1 truss to assist his partner. Japanese astronaut Koichi Wakata
operated the Canadarm2 from inside the Destiny laboratory.
While doing the connection work, the duo demated ammonia fluid lines
from a jumper box that enabled ammonia flow during the repair
spacewalks. After experiencing some difficulty disconnecting a fluid
line the spacewalkers reported seeing ammonia flakes escaping a valve.
As a precaution, mission controllers asked the spacewalkers to inspect
their spacesuits for possible ammonia contamination. Once they were back
in the Quest airlock the duo conducted more ammonia decontamination
procedures on their spacesuits. All four fluid lines were successfully
reconnected to the newly installed pump module restoring ammonia flow.
Afterward, Hopkins and Mastracchio completed electrical connections
to the pump module. Power was successfully restored to the ammonia pump
module. However, flight controllers will perform more tests before
restarting the pump and returning it to full functionality.
The duo was originally scheduled to finish the installation work on
Monday before mission controllers detected a spacesuit configuration
issue at the end of Saturday’s spacewalk, in which the spacewalkers
removed a faulty pump that experienced a problem with its internal flow
control valve Dec. 11.
The suspect pump was removed from the starboard truss and parked in a
temporary location on the station’s Mobile Base System rail car where
it can stay until at least next June. Managers decided an extra day of
preparation was necessary to get a backup spacesuit ready for
Mastracchio.
The Christmas Eve spacewalk lasted seven hours and 30 minutes. This
was the 176th spacewalk in support of space station assembly and
maintenance. Mastracchio holds 51 hours and 28 minutes spacewalking time
over eight spacewalks. Hopkins holds 12 hours and 58 minutes over two
spacewalks.
No comments:
Post a Comment