The 3rd and 4th spacewalks became interesting to the general public when the 3rd spacewalk had to end early due to a malfunctioning spacesuit! A malfunctioning life support system was causing higher levels of carbon dioxide in one of the suits, and the safety parameters called for an end to the spacewalk. It was close enough to the end of the planned walk that NASA decided to bring in both astronauts and continue their tasks on the next one.
During the 4th walk, the astronauts completed the battery work successfully and got back on schedule.
I find this particular problem very interesting, because of my work as a flight director at the CMSEC Space Center. During our mission simulations, the most common damage control item I present in the simulators is the CO-2 Scrubber damaged system. So for any of you readers who frequent the simulations at the Space Center, the next time you have to work on the CO-2 scrubbers, just think of the poor astronaut who has to deal with that in zero-gravity!
The astronauts are having a day off today, halfway through their mission. The 5th spacewalk is expected to take place on Monday.