The software work was under way for much of the week, updating more than 1.5 million lines of code in the onboard command and control computers. Expedition 10 Commander Leroy Chiao and Flight Engineer Salizhan Sharipov also measured cardiovascular systems and conducted routine mid-term physical evaluations.
The software upgrade generally improves the operations of onboard computers and, through its updates, decreases the number of workarounds or, Station Program Notes (SPNs), ground flight controllers must use by about 300.
Sharipov began early preparations of gear that will be used during the two crewmembers' Jan. 26 spacewalk. During the spacewalk, they will install a new work platform on the exterior of the Zvezda living quarters module, hook up a small robotic experiment and install other scientific gear on the Station's exterior. The first of two planned spacewalks for Expedition 10, it will be conducted from the Russian airlock using Russian spacesuits.
Formal preparations for the spacewalk begin Monday. The 4½ hour spacewalk will be broadcast live on NASA Television, beginning at 12 a.m. CST Jan. 26. The spacewalk is expected to begin about 1:25 a.m. CST.
All Station environmental control and life support systems are operating well, including the Elektron oxygen generating unit. Though Saturday is planned as an off duty day for the crew, flight controllers plan a reboost of the Station's altitude of about 5 statute miles (8.5 kilometers) using engines on the attached Progress cargo craft. The reboost engine firing will last almost 20 minutes.