 The problems with seating the second RSU set the spacewalkers back in the timeline by approximately two hours, but after Altman asked Massimino and Good how they felt, they replied they were doing well and felt fine to continue. Flight controllers on the ground evaluated the consumables for the two spacesuits, and decided that if Massimino recharged his suit's oxygen in the airlock, the pair could safely continue with the battery installation. After moving to the battery unit site, Good and Massimino removed one of the original battery modules from Bay 2 of the telescope, and replaced it with a new unit. The batteries provide power to the telescope when it passes into the Earth's shadow and its solar arrays are not exposed to the sun. The spacewalk officially ended at 20: 45 UTC, for a time of seven hours, fifty-six minutes. It was the twentieth spacewalk to service Hubble, bringing the total time in EVA servicing the telescope to one hundred forty-four hours and twenty-six minutes.
