Yesterday’s spacewalk turned into a marathon session for the mission specialists and was apparently only completed by the application of some brute force (use a larger hammer) sort of action by the mission specialist Massimino.
Of course what he was working on has been in orbit nearly 20 years, was sitting in storage on the ground before that, and was never actually intended to be repaired in orbit so he actually accomplished an incredible task.
NASA’s blog entry at the end of the fourth spacewalk read as follows:
“The fourth of five STS-125 spacewalks concluded at 5:47 p.m. EDT. It was 8 hour, 2 minutes, the sixth longest spacewalk in U.S. history. During their walk in space, Good and Massimino experienced trouble removing a bolt from the STIS handrail. Massimino eventually was able to manually remove the handrail by pulling it free.
The spacewalkers were then able to finish the rest of the STIS repair work without issue. Due to the lost time spent on the handrail, the New Outer Blanket Layer work planned for installation did not happen. Mission timeliners will work various options for tomorrow’s fifth and final spacewalk.”
Today the mission specialists began an hour early but NASA reports that they plan to complete the spacewalk in the scheduled 5 hours, 45 minutes. The priorities are replacing batteries and a guidance sensor FGS-2 (necessary for fine control of the position of the scope.)
The final job for mission specialist Astronauts John Grunsfeld and Andrew Feustel will be to wrap the HST in thermal blankets which help maintain the delicate electronics at very low temperatures.
See live feeds of the final spacewalk at space.com, nasa.gov, or on NASA TV.