So the guys at 343 have answered few questions, and said something about each apart is an episode that is part of a full campaign. My question is, will they add missions even when we finish the spartan ops campaign. Like a second season. I think it would be nice to explore our spartans as characters.
I think they said if season 1 was successful they would do more seasons.
If it gets popular they probably will, so I would say that we all have to play them to get more missions! 
So glad they might do more than one season if they wish to.