Whirligig Girl

My planet packs usually try to bring something new to the table gameplay-wise, rather than just adding new planets in a new solar system, I like to change things up with weird homeworlds, rather than just Earth/Moon analogues. Here's a couple examples of what I mean:

Alternis Kerbol Rekerjiggered
Alternis Kerbol was not originally developed by me, it was developed by NovaSilisko, but the weird homeworld mechanic involved in the mod is a major part of what drew me to rekerjigger it. In Alternis Kerbol, the homeworld is still Kerbin, but it now orbits a warmer, bluer Jool as a large satellite. This alone changes up the dynamic significantly, with wide ranging effects on early game exploration, orbital mechanics, and the general feel of the game.

Toy Solar System
Toy Solar System was another one of my early mods, which rescaled the solar system to 1/10th scale. Like AKR, it was a remake of an older mod, and it has since been supplanted by Sigma Dimensions, which generalizes rescale to any scale factor you want. Although these changes affect the whole solar system, playing at this scale is a truly different experience compared to stock scale, perhaps even more so than the difference between stock scale and Real Solar System.

Little Green Men from Mars
Initially developed by Probus, I took over and cleaned and polished a few things. This mod was effectively Real Solar System, except the space program starts on Mars. The delta-v to Mars orbit is actually comparable to the delta-v to stock-scale Kerbin orbit, and thus allows Real Solar System to be effectively played with stock parts. But more than that, it also introduced a new challenge: re-entry. In stock KSP, re-entry and landing is as simple as parachutes and maybe a heatshield. On Mars, you have to contend with the minuscule atmospheric drag while still dealing with heating. As a result, all returns require some care and effort put into them. This notion of difficult returns will come up later a few times.

Alien Space Programs
This one is the most obvious example of this tradition. Initially developed as Duna Space Program between myself and Sigma88 (and now maintained by Gordon Fecyk), Alien Space Programs generalizes the concept of Little Green Men from Mars, but for the stock Kerbol system. Duna, Eve, and Laythe were the first worlds to get made. Duna was a lot easier than LGMfM, and indeed was much easier than Kerbin. Eve was a particularly difficult challenge, and getting to orbit in career mode is especially difficult. As far as I'm aware, Eve Space Program is the only mod which places the space center on a conventional Super-Earth planet (albeit at Kerbal scale). Laythe Space Program plays very similar to stock KSP at first, but like Alternis Kerbol, you have an entire satellite system to explore right off the bat. I later added a few more modes. Jool Space Program plays actually quite a bit like Real Solar System on Earth, since stock-scale Jool's mass and gravity is similar to a full-scale Earth. The difference being, once you're in space, you have some relatively small moons to go and explore. Tylo Space Program was similar to Laythe Space Program and Alternis Kerbol, except crucially, the lack of an atmosphere around heavy Tylo meant that each return was a big deal, as Tylo is the hardest planet to land on delta-v wise in the whole stock system. Tylo was also different enough to warrant a mildly modified tech tree. Finally, Minmus Space Program was added for those who like it really really almost comically easy. Perhaps one day Gordon or myself will add all of the stock planets. And back when I was actively working on ASP, I always wanted to generalize the concept to other planet packs.

Sudric System
Holy System of the Vernians, or as it would later be halfassedly released as, Sudric System, was going to be a pretty major conversion when I was originally working on it. The planet you start on is significantly less massive than Kerbin, (though still much heavier than Duna), and I was going to have a whole steampunk spaceship parts architecture and space-religion-lore. After I got stuck for a long time, I ended up releasing it as-is and cancelling the project. This is probably the weakest of the homeworld weirdness, but it's there. And the massive binary companion around the homeworld definitely is a far cry from the Earth-Moon system.

Whirligig World
The jewel in the crown of absurd homeworlds, Whirligig World's Mesbin is not even slightly like Kerbin. It is an oblate spheroid rotating once every 28 minutes and massing 71 Kerbins, and it's completely airless. The colonists crashed on Mesbin by mistake, they were aiming for one of Mesbin's many moons. Geostationary orbit is extremely low, and the static moon "Statmun" rests there. The fast rotation period means getting into orbit is actually slightly easier than on Kerbin, but the lack of atmosphere means you have to do a powered landing every time. And the incredible mass means that even when you do get into orbit, launching up to the moons or escaping the planet requires a hell of a lot more fuel. For those who still want to explore the vast Kaywell/Gememma star system, there is an optional patch available to move the homeworld to Kerbmun, Mesbin's Kerbin-sized, Kerbin-like moon. In this mode, the homeworld is still significantly different from Kerbin, in that there's an extensive system of moons, and the parent body is still the extremely weird Mesbin. Mesbin's so different that I had to redesign the tech tree so it'd make sense--starting with the Tylo Space Program tree.

Where to next?
For a while now, as Whirligig World gets closer and closer to a 1.0 release, I've wondered what comes next? What's my next major planet pack? What can I do to the homeworld to make it weird? I've explored a few options.

Tiny, high-pressure-atmosphere planet. This would be the polar opposite of Mesbin. You would start out not with rockets, but with aircraft parts, and jet engines would be enough to get you to space, and maybe even flybys of small moons. I actually did prototype this, and unfortunately it turned out to just not be very fun. With the low gravity and high pressure, flight was extremely slow, and since KSP's piloting controls are not suited to continuously flying a plane in the same direction for minutes at a time, I figured that the idea probably wouldn't work that well in practice. It's still something to consider some time.

Asteroid Space Program. This would still be quite different from Mesbin, but shares some similarities. In this mod, you'd start on a large asteroid, something like Vesta or Pallas. The tech tree would also be completely reinvented to provide only terrible cold-gas thrusters at first, slowly unlocking gunpowder solid rockets, monopropellant rockets, and only around the time you need to start landing and launching from planets would you get the liquid fueled rocket motors. I have mocked this up and have had some fun with it, and I think it's promising enough to go forward with the idea. The project even has a name--Breathless, though with the recent Keanu Reeves memery, perhaps Breathtaking would be better? The name of course refers to the lack of atmosphere on an asteroid, though it's worth noting of course that the name could apply to Whirligig World and most of the Alien Space Programs.

Super-Earth Space Program. Following in the footsteps of Eve Space Program, I'd like to make a Super-Earth Space Program one day. It'd have to be at full RSS scale, though, and support Realism Overhaul. I want a major point of the mod to be a case study in how space programs might manage on planets much heavier than the already quite massive Earth. The trouble there is that RSS-scale mods are much harder to get to look good. RSS barely manages to look passable at that scale. I've only had limited success with RSS-scale/style planets, and that was in Alternis Sol.

It's possible, with homeworld switching, to implement several of these ideas into a single planet mod. And since after all this time I'm starting to get burned out on making planets, maybe that's a good idea. As it stands right now, my problem with developing new planet packs is that for almost a year now, all I've really been doing is polishing Whirligig World, not really adding much new to the mod in the form of planets. And that's fine--the system's plenty large enough with nearly 40 bodies, but it does mean two things: 1) 40 bodies is so much, how am I supposed to make more bodies that are sufficiently different from those already in WW? 2) I'm out of practice, and find it difficult to produce new worlds.

When I think about building new systems, I often think on very large scales. I like thinking about unique orbital arrangements, especially those that showcase real phenomena we see in exoplanets and simulations, but I end up writing and drawing up systems with several dozen bodies in them. That's not too many worlds to define the orbits, masses, densities, and atmospheres of. But it's so much to actually make, painting the maps, writing the terrain configurations. For this reason, I usually try to limit myself to 15-20 bodies, about as much as the stock Kerbol system.

All of this is compounded by the fact that I struggle with depression, and actually continuing anyproject is hard. When I think about how long it's taken to get Whirligig World to a state where it is almost ready for 1.0, and think about how much work is going to go into making a new mod from the ground up, I'd be lying if I said I wasn't really intimidated. And that's not even mentioning that I still have quite a few projects which are inactive that I'd like to get active again, like Alternis Sol and Ultimate Solar System.