After re-reading my post, I can see I should clarify further.
A mission can be done X times (completions) and each completion needs to be done Y times (attempts) to complete it.
So when you fail a mission, you lose all of the attempts you've made in it thus far but don't lose any of the completions.
So for transporting the bomb, there are 10 attempts for each completion (of which there are 20).
I hope this makes more sense. It might make more sense to say sometime like:
Quote:
Risks: Potential for bomb detonation (massive hull damage and attempts reset)