Hair-raising is one way to describe the Ariane 5 abort which occurred after the main engine had fired for several seconds.
Like the space shuttle, the Ariane 5 rocket’s core cryogenic main engine ignites seconds before twin solid-fueled boosters, giving computers a chance to gauge the vehicle’s health before firing the strap-on motors, which can’t be turned off.
Actually, there’s one way to turn them off: the command destruct (that is, the safety self-destruct) package. But you get the idea.
Obviously far better than a failure, this anomaly will blow the Arianespace launch schedule out of the water.
Beyond just the anomaly resolution (expect it to be blamed on a glitch; just a prediction), all sorts of space hardware would have gone to internal (battery) power, ordinance may have been expended on the umbilical pulls, etc..
You don’t get many of these!