"Why have NASA been holding up the launch of a multi-trillion dollar rocket & cargo for nigh on TWO months, for the sake of a connector, that no doubt could be replaced in less time than it takes to run a marathon?"

Because NASA generally can't just change part of the shuttle's design without massive safety concerns being addressed and thoroughly tested? No matter how trivial the change is, it's space. It's not a car, it can't pull over to the lay-by and call for roadside assistance halfway through a mission if their bodge doesn't work as planned.

People tend to forget that the shuttle is actually an experimental craft. It was never meant to be flying for so long and if Nasa's budget hadn't been repeatedly cut all the way up to the late 90s it would have been retired and replaced already. Anyway that's why they take so long over everything; replacing parts in an experimental craft is a lot more involved than replacing parts in a mass-produced craft.

It should also be added to anon that it's a very big space craft, it can't just fly into space whenever it feels like. They need to get a launch window before going - http://en.wikipedia.org/wiki/Launch_window

The thing is several storeys big, so can't just be switched in seconds. Which means the launch window is missed, taxiing off the launchpad (you can't do major fixes there, not enough equipment, driving back to base, fixing, finding another window, booking (in case some other non-public planned nasa govt/secret flights are taking place), then taxiing back, configuring flight control, launching. It does actually take longer than your marathon.

The launch is "not, however, dependent on solving the ongoing fuel sensor problems which... monitor liquid hydrogen levels in the vessel's fuel tank and prevent it running dry, potentially triggering a catastrophic explosion". Sounds like the M$ philosophy in action.

Now we know why NASA astronauts need diapers.

It looks a lot harder than just soldering the pins and plugs together...

http://www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts122/solderingteam.html

http://www.nasa.gov/images/content/122488main_ECO_sensors.jpg

Might need a lot of spanners, and a big ladder...