[mhandley]

They've been developing the BE-4 engine for five years already, and the current plan is for that to be the first stage engine on the next ULA launcher. By the time they get round to launching the New Glenn, the BE-4 that it will use on the first stage will have already been tested courtesy of ULA. If I understand correctly, the second stage engines will be a development of what they're currently using on New Shepherd. This means they'll have already done much of the testing and development in other launch systems, so perhaps the step to a heavy-lift launcher is not quite so outrageous as it might first seem. Still, a lot can go wrong that isn't related to the engines, as SpaceX has discovered.