I just started playing this game and I'm to level 16 in career. I thought a bit about launching multiple payloads on one rocket, and now that I have the Saturn V rocket, I've found you can do just that. So far I have been able to launch two relatively small payloads simultaneously without much difficulty. I haven't seen much talk of this. The SLS claims to be able to carry three small payloads but I cannot confirm this. Please feel free to add your own experience and examples. As I said, I'm only on mission 16 and I'm still waiting to get certain modules, so there could be much better methods for this than the Saturn V.
In this wiki I want to discuss the best combinations of rockets and payloads for rapid Space Station development.
The Saturn V rocket is the first large rocket obtained through the missions. What makes it special for the purpose of carrying multiple payloads is the Saturn V Payload Fairing. Like a normal fairing, the Saturn V Payload Fairing will open to reveal the payload underneath. However, the Saturn V Payload Fairing is different from most other fairings in that it has a flat top which fits a small stage. Once the Saturn V Payload Fairing breaks away, the two parts will separate, and provided both contain a payload, neither will disappear.
The Saturn V is a three stage rocket with two large stages, the second of which tapers at the top to hold a medium stage. From what I have found, the Saturn V First Stage and Second Stage are both necessary when launching two payloads with the Saturn V. However the third stage can be any number of medium stage rockets. I have achieved success with the Saturn V Third Stage, the N1 Block V, and the Proton Second Stage(Can be used as a third stage). The Saturn V Third Stage and the N1 Block V work especially well, because they contain a small space at the top where a payload sinks in. This is useful because the Saturn V Payload Fairing is too small to contain many small but tall payloads (for example, the Refuel Module and the ATV) without this space.
You may want to attach maneuverable stages to one or more of your payloads for various reasons. Tugs are ideal for this as they provide maneuverability while minimizing weight.
I've come up with some combinations of payloads which can easily reach orbit using the Saturn V. Feel free to add your own!
Please experiment, comment, edit with your discoveries!