Well, there are a lot of unknown variables in your dilemma... I am by no means a ranked expert or even above average with the program, but if I were to do this, naturally I would make each stage a separate object... I believe I'd go so far as to make each stage an individual figure with its own sequences. Then join the figures together in the scene(s) and each rocket stage would have its own sequences for when it breaks free and spins, falls, tumbles, etc.
Of course, I wouldn't consider trying to make the whole launch and entry into space in one scene. I'd create individual scenes for:
- Launch Pad
- Ascending through the lower atmosphere
- Break-Off scene for each individual stage departure
- Maybe a mini-version showing the rocket from ground level as it trails far above as a white vapor trail.
Otherwise you'd be asking for a lot of headache to create the effect of the atmosphere darkening and thinning through the entire flight.
Is that what you're quandering over?
Also, it would be really good to see what some of our seriously advanced folks suggest, because, as I said, and as my signature states, I am by no means even close to being advanced with animation and such.