>>12372090Additionally, bigger and fewer engines mean you have less redundancy.
If an engine fails, unless it's right in the centre, you have to disable the opposite engine to compensate.
If you have 1-3 engines, losing an engine means losing the rocket.
If you have 4 engines, losing an engine means losing half your thrust, which may or may not cost the mission depending on when it happens.
I'm no expert, but I figure you need at least 7 engines in order to be able to lose one at any stage of the mission and still be able to succeed.
