Delta 4 launch last night

You should have shot at a higher ISO level. A higher exposed photo brought down in post at higher ISO will have less noise than a lower ISO photo that has to be raised up in exposure.

I'll do that next time. Should 400 be good enough?

Depending how much brighter, I wouldn't even bother about the ISO: just open up the aperture more than you did for this shot (f/22). Already, an f/16 aperture would have let in x2 as much light.
Am.

Why raise the ISO and introduce more noise? Better yet, why shoot this at F22? Open it up some. I don't know the noise characteristics of the 5D. Maybe ISO 200 or 400 would be clean, but generally, the higher the ISO, the higher the noise.

Nice shot all the same
The darker skies just hi lights the launch more

The EXIF says it was at f/16

Not a bad shot, & a bit of noise reduction (NR) will easily help it out.
Before shooting something like that, it doesn't hurt to try some test shots a few days before the event. Then you have some time to get suggestions from us here.

I thought it was f22......either way I was afraid the rocket would overexpose the image, it's happened before and it ruined the photo. either way, there's another going off in August if it's a night launch I'll take another crack at it. I liked this one just a tad dark

the 5d does high iso well, i regularly shoot 800 in bars and clubs and they look great even with little noise reduction

The plume WILL over expose, but there isn't not much you can do about that. It is damned bright! What other light you let in will depend on just how you want it to look. Want to have free reign? Take one exposure just before the launch with the light you want. Then shoot the launch like you did this one, or a bit brighter and blend them.