Back when the current Hubble servicing mission was in jeopardy, there was talk that perhaps the repairs could be done robotically, without the expense or danger of a manned repair mission.
Well, on Day 2 of the repair spacewalks (EVA’s), I think we now know why sending a manned team might have been a good idea.
On the first EVA, one of the bolts holding in the old camera (WFPC2) in wouldn’t release. After running through every single contingency plan, Andrew Feustel eventually had to get out a non-torque limited wrench, and just plain guess how much torque to apply to the bolt, hoping all the while that it didn’t shear off. Maybe a robot could have handled that one, but I’d rather have a former Jaguar repair jock on the job (h/t commenter Peter).
On the second EVA, the situation was equally tricky. While the astronauts successfully extracted the gyroscopes, a pair of the new ones simply would not fit in. Luckily, they were able to grab some refurbished spares, that fit in just fine, but not after a couple of nerve-wracking hours digging deep into the contingency plans.
So, I’m two-for-two on being glad that actual humans were involved in these tasks. Given the trickery that’s going to be involved in tomorrow’s repair of the Advanced Camera for Surveys (think 100+ screws taken out by a guy wearing high-tech ski gloves), I’m guessing that tomorrow will be another hair-raiser.