Well, you will be banished from Compass Rose for the Captains dinner, which is formal. If it is space you are worried about, get some of those "space bags", the kind that you suck out the air with a vacuum cleaner. You will be amazed at how flat and compact they become! But, you will have to send out your suits for pressing once you get on the ship. Space bags or not, I do this anyway as regular packing makes a mess out of jackets.
