A SpaceX Falcon 9 rocket has exploded at Cape Canaveral
In looking at failures, asking "What changed (was different)" in this case, is one generally useful approach...Based on previous comments, the most likely failure scenario seems to be related to the new use of super-cooled LOX - and I have to ask, was the temperature at the pad, at the time of the launch, significantly higher than during previous launches involving super-cooled LOX?  If so, is there a possibility that the higher temperature differential could have been a contributing factor in the cause of the failure?(Kind of the exact opposite of the case of the Challenger, where low temperatures were a critical causal factor of the failure)