In the quest to build the ultimate all-purpose vehicle, 96 kerbalnaughts boarded the Duna Colonial Transporter and set out to make Kerbals a multiplanetary species.
Full mission album
Last year, after SpaceX announced the Interplanetary Transport System, I decided to build something like it that was as close to stock as I could get, and ended up making this. It's a fairly complex design that's taken a long, long time to tweak to perfection. Imgur isn't great for long explanations, so I'll go into detail here about the technical aspects and what I've learned from the mission. I started out with the following parameters in mind:
A separate set of vacuum and atmospheric engines
Around 100 Kerbal capacity
Larger than normal diameter
The first four are obviously taken straight from the design of SpaceX's ITS, but the last one was a challenge. I've done fuel tank clipping before to get vehicles that exceed the largest stock tank size, but I had never attempted to create one that was larger across multiple stages because it's really hard to do right. I designed the upper stage/spaceship first with all the capabilities I wanted before moving onto the booster because its interstage would depend on how the ship turned out. Since the editor only allows for a single connection between two parts, the whole stack is only connected a single 1.25m decoupler that attaches to the docking port on the aft of the ship. From there, adapters widen it out and connect to the booster. Fairings wouldn't work to cover up the interstage area, so I built up radiators and it worked surprisingly well. Compared to the spaceship, the booster is pretty simple and my only parameter was to use only Vector engines, since the ITS will use bunches of Raptor engines. I put in as many as could physically fit on the booster.
All of the serious business is crammed into the end of the spaceship. The most notable pieces are the engines, and they were definitely the easiest to install, but there's also a probe core, batteries, monoprop tanks, drills, lights, and a docking port. Since it's designed the way it is, pretty much nothing can be attached to the sides, which means that real estate on the bottom of the ship is in high demand for all the miscellaneous components that it needs. There's also an ISRU converter and ore tanks jammed up somewhere inside it, but those don't need to be exposed.
I put the docking port in with no specific purpose in mind, but as with most ships in KSP, you end up needing one at some point. And indeed, it actually saved the first mission to Duna. I had forgotten to put an antenna of any kind on the ship before launching it to Duna unmanned, and only realized as it was on an escape trajectory. So I had two options: Abort and launch a new one with an antenna or... fire off another rocket to catch up and deliver one. Yep, I went with the second option. A satellite dish was sent after the ship and successfully attached via docking port. It was a little ridiculous to have this awkward antenna between the engines that almost scraped the ground when it landed, but it worked. Afterwards, I immediately put in the antennae it has now.
Those of you with good eyes may notice that the exit hatches are right above the solar panels. I did not catch this until I was already on Duna and had to unload 96 kerbals without breaking the panels. Sometimes you just don't figure things out until you're doing it for real.
Another thing I learned is that the ore drills suck up a lot of electricity. I added more batteries after the first mission, but I still needed more. In fact, the one limiting factor to how far out in the solar system the ship can go may be its capacity to generate power.
I also have trouble with landing it because it has a tendency to bounce after touching down. When I returned from this mission, I actually went and did tests with different settings for the spring/damper to try to minimize this. It's a little stupid to plop this big ol' multi-ton spaceship down and have it bounce.
The best part about this ship is that it is definitely capable of going pretty much anywhere since it has around 5000 m/s of dV and can top that off any time it is on the ground. I got to experience the math of dV firsthand when I noticed that the first half of the ship's fuel only supplies about 1 km/s since it starts out very heavy (it's over 1 kiloton fully fueled). Aside from maneuvering issues (there's just no way to get something that heavy to turn fast), it's very easy to use and low-risk since it has the dV budget to not need aerocapture. Even when coming in to reenter Kerbin from an 80x80 orbit, I didn't need a heatshield and just slowed my velocity propulsively as I hit the thicker part of the atmosphere.
It's easily the most complex and complete ship I've made, and it can stay in space indefinitely. I really look forward to sending it wherever it can go. Next stop: Jool!
Craft download (only 1 mod part from Kerbal Reusability Expansion): https://kerbalx.com/CommanderSpork/Duna-Colonial-Transporter