[image-78]While the ground team continues troubleshooting an issue with one of the International Space Station’s two external cooling loops Friday, the Expedition 38 crew focused on biomedical research and preparations for the robotic capture of a commercial cargo craft.
Overnight, flight controllers attempted to power cycle the starboard truss pump module in an attempt to fix the incorrect positioning of the module’s flow control valve that caused the pump to malfunction Wednesday. The attempt was unsuccessful. The engineering teams have concluded there is no way to modify the valve’s firmware so that the valve can be commanded outside of its firmware limits. There is still additional work to be done in understanding if the thermal loop can be warmed by other methods, which could include manipulating other valves in the system or adding heat to the system via heaters.
While the engineering evaluations continue, station program managers will have further discussions on potential contingency spacewalk planning that could result in multiple spacewalks to replace the pump module beginning as early as late next week.
[image-51]With the station currently in a stable configuration, the six astronauts and cosmonauts on board focused on science and robotics and prepared for a planned Russian spacewalk.
Commander Oleg Kotov and Flight Engineer Sergey Ryazanskiy conducted a preliminary review of a spacewalk they will perform on Dec. 27. During that excursion, the two cosmonauts will install high and medium resolution cameras on a platform outside the Russian segment of the station, attach a foot restraint for future spacewalking tasks and remove and replace several experiment packages.
At the controls of the robotic workstation inside the station’s cupola, Flight Engineers Mike Hopkins and Koichi Wakata rehearsed grapple procedures for the upcoming capture of Orbital Sciences’ Cygnus cargo ship on its first commercial resupply mission. For Friday’s practice session, the two astronauts practiced the techniques they will use to capture Cygnus with the station’s 57-foot robotic arm, Canadarm2, if the vehicle is in a misaligned position. Cygnus is still scheduled to launch Wednesday from Wallops Flight Facility in Virginia and rendezvous with the station on Dec. 21. Mission managers have deferred the final decision on whether to proceed with or postpone the launch of Cygnus until more is known about the station’s flow control valve issue.
Wakata and Flight Engineer Rick Mastracchio removed and replaced an assembly inside the Advanced Biological Research System, or ABRS, a research facility with two independently-controlled chambers that can grow plants, microorganisms and small arthropods.
Afterward, Mastracchio assisted Hopkins with the Body Measures experiment, which collects anthropometric data to help researchers understand the magnitude and variability of the changes to body measurements during spaceflight. Predicting these changes will maximize crew performance, prevent injury and reduce time spent altering or adjusting suits and workstations to accommodate anthropometrics.
[image-94]Mastracchio took a break from his work to talk with Marcia Dunn of the Associated Press and SPACE.com’s Tariq Malik, answering questions about the loss of the cooling loop and the research taking place aboard the complex.
Wakata and Hopkins rounded out their day with the Reversible Figures experiment, which tracks how the adaptation of an astronaut’s neurovestibular system to weightlessness may alter 3-D visual perception.
Flight Engineer Mikhail Tyurin performed the Uragan Earth-observation experiment, which seeks to document and predict the development of natural and man-made disasters on Earth. Afterward he conducted routine maintenance on the life support systems in the Zvezda service module.
The thrusters of the ISS Progress 53 cargo ship docked to aft port of Zvezda were fired at 9:57 a.m. EST for the second of two reboosts of the station to set up the correct phasing for Russian visiting vehicle operations next year and to modify the phasing capability for Cygnus for two-day rendezvous attempts in December. The first reboost in this series, a 7-minute, 41-second burn by Progress 53, took place Wednesday.