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[1.12.5] The Kerbol System B-Sides

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Ultimate Steve's Kerbol System B-Sides

Hello everyone! The Kerbol System B-Sides mod is a set of Kopernicus configs to adjust the stock system to provide interesting navigational, piloting, and engineering challenges, while ramping the characteristics of each world up to 11.

This mod is inspired by the B-sides from the game Celeste. Each level in the game (except the last one) has a B-side, an optional non-canon remix of the level with increased difficulty, largely keeping the same theme, expanding on what made the original challenging. There are also the C-sides, which are even harder than the B-sides.

This mod was created because I found that the stock Kerbol system had gotten a bit too easy for me. Rescales and hack gravity challenges really only increased one or two dimensions of what made things difficult, and the planets were still largely unchanged. Planet packs are largely based around stock difficulty, and RSS/RO/RP-1 can get to be a bit too much sometimes. When I first started playing KSP, everything seemed impossible. Then I gradually learned how to do everything, to the point where I now know you can do a grand tour in under 8 tons. I used to plan for weeks how I would get to Duna, and I would be so elated when I finally got there. Now, I just simply go to Duna. This mod aims to restore those senses of impossibility and accomplishment while still remaining possible with stock parts (probably).

The difficulty tuning is roughly based off of the Mun being a bit easier than stock Tylo. Not every world is scaled exactly like this, but that is the general idea.

Brief Descriptions Without Many Spoilers (for those who would rather discover the challenges themselves)

  • Kerbol - Just a size increase to make interplanetary transfers a bit more costly.
  • Moho - If you thought old Moho's orbit was challenging to get to... Make sure to pack radiators!
  • Eve - Good luck.
  • Gilly - Gilly really does want you to be there.
  • Kerbin - MOUNTAIN!
  • Mun - If you can get there, it is quite the view!
  • Minmus - Inclination? What's that?
  • Duna - It's atmosphere has teeth!
  • Ike - About 10x more obnoxious than usual.
  • Dres - Dres doesn't exist, silly!
  • Jool - I dare you to land there.
  • Laythe - Might have a hard time finding a place to land.
  • Vall - Also might have a hard time finding a place to land.
  • Tylo - Also, good luck.
  • Bop - The Kraken wants you to come closer. He promises he won't bite.
  • Pol - Because what's a video game without a pit of spikes?
  • Eeloo - Want to go sledding?

All of the details



  • About twice as wide
  • Supposed to be 2-3x as bright but I have tried many things and I can't get it to work. Was supposed to make ion engines less painful (and Moho more painful).


  • Moved to a lower, more eccentric, more inclined, and more argumentOfPeriapsis'd orbit.
  • Higher gravity and radius
  • Lava oceans
  • A super hot atmosphere


  • About twice as big
  • About twice as high gravity
  • Mountains about twice as tall
  • Atmosphere about twice as high
  • Atmosphere about thrice as thick
  • Might be impossible, may rebalance


  • Smaller
  • Rotates very fast


  • Twice as big
  • About 1.8g surface gravity
  • Atmosphere 1.8x as high
  • 1.6atm sea level pressure
  • Landscape scaling greatly exaggerated, enjoy flying through the mountains!
  • Orbit made slightly imperfect to increase the difficulty of interplanetary transfers


  • Significantly closer to Kerbin
  • Larger
  • 0.87g gravity
  • This makes it a really good gravity assist machine, but its orbit is now slightly imperfect


  • Terrain scaling exaggerated
  • Orbit is now highly inclined and somewhat elliptical
  • Slightly larger
  • Higher gravity
  • Rotates in about an hour. Makes lining up a landing spot on the flats require some forethought.


  • Significantly larger
  • 1.7x gravity
  • Atmosphere is now significantly shorter
  • Atmosphere is now slightly thicker at sea level
  • Orbit tweaked to be more imperfect


  • Now orbits obnoxiously close to Duna. There is a very narrow corridor of space where you can orbit and not burn up in Duna's atmosphere or get ejected by Ike.
  • Increased radius
  • Increased gravity


  • Orbits retrograde
  • Doesn't exist
  • If it does exist, you might want to look at your radar altimeter


  • Surface gravity is 2g (was 0.8g) to increase transfer Delta-V
  • Now has an ocean you can land in


  • Significantly less terrain pokes up out of the water
  • What terrain that does poke out is hillier than usual
  • Slightly bigger
  • Atmosphere shorter and thinner
  • Significantly closer to Jool


  • Bigger
  • Higher gravity
  • Now has an ocean, presumably the increased solar heating got to Vall and it is slowly melting away...
  • Terrain significantly exaggerated, may take time to find a landing site that isn't a sheer cliff dropping into a lake


  • 3.8g gravity
  • 50% bigger
  • Was originally gonna be more but it turns out that's plenty hard already


  • Significantly smaller (I wanted it to be even smaller but it broke)
  • About 7g gravity
  • Nearly flat
  • The Kraken decided to get into black hole forging but hasn't quite made it yet


  • Increased orbital inclination
  • Increased gravity and size
  • Drastically exaggerated terrain


  • Significantly increased eccentricity and inclination
  • Increased gravity and size
  • Lowered surface friction and exaggerated height map (I want to make a sled)

More Pictures



The Aeris 3A flying at about its service ceiling with a view of the Mun


A Mun landing (without enough fuel to get home)


A test craft over Laythe, over Jool


Another view of the mountains


The world's first Kerbin-B SSTO, was unable to return due to re-entry heating. If anyone can make an SSTO that can return (and carry a payload), you have my admiration.


BSV-01 Europa orbiting Duna


Known Issues (I am accepting help)


Increasing luminosity doesn't work. I have tried several things, solar panels still produce the same amount of power close to Kerbin. I might have to nuke Kerbol and recreate it from scratch (and reparent every other planet) to get it to properly work.

New oceans are not showing up in scaled space. I've tried a lot of things. The oceans still show up when you get close, though.

Some bodies look like their vanilla versions in scaled space, ignoring any additional PQS mods - especially evident on Laythe. I've tried a lot of things, the issue is likely related to me modifying existing worlds rather than creating new worlds.

Sometimes there were massive FPS drops around Duna due to Ike's proximity. I think I've fixed them but let me know if it pops up again.

Vall FPS drops, might have been my imagination.

Jool's ocean is disappearing at higher than normal camera angles.

Jool's sky texture sometimes partially disappears at the surface.

I can't figure out how to adjust minimum safe altitudes, so don't trust the KER readout, and debug menu teleportation might put you inside a mountain.

Time warp limits are not implemented yet (this is mostly just laziness). Install better time warp continued, you'll probably need it anyway for using ion engines more than normal.

Development Outtakes



This still happens, I don't know why, but someone took a bite out of the Joolian sky


Minmus was extremely spiky for a while and I didn't know why, I think it had something to do with scaledspace.


This was an attempt at fixing Minmus. Needless to say, it didn't work. Neat that we can play Minecraft in KSP though.


My initial attempts at rescaling (pre Sigma Dimensions) did not move the ocean texture, but did move the collider (or vice versa? I can't remember). This resulted in the appearance of levitating ships when they were splashed down.


I'm pretty sure Eve isn't supposed to be that purple.


I fixed the spikiness, but the color scaling was the next problem.


When I shrunk down the Laythe terrain, I had a weird issue with some of the ocean disappearing. There is apparently a PQS mod that removes ocean tiles below land to reduce lag, and I had to turn that off as it was still set to the default heightmap.


I have no idea what happened here, but I managed to create two Gillys.


Jool's ocean was originally a surface, but the surface didn't work properly so I made it an ocean instead.


Another shot of spiky Minmus for good measure.

Thanks to everyone who helped me fix these issues!


  1. Install Kopernicus Planetary System Modifier and its dependencies via CKAN.
  2. Install BetterTimeWarpContinued via CKAN. It isn't strictly necessary but it will make ion burns far less painful, and will eliminate any problems from vanilla time warp limits still being applied on smaller bodies.
  3. Install the latest version of Sigma Dimensions from GitHub (https://github.com/Sigma88/Sigma-Dimensions). The version on CKAN is not up to date (was made for 1.3.1). I'm unsure if the version on CKAN will work, it's best not to chance it.
  4. Install the Kerbol System B-Sides mod from GitHub (https://github.com/UltimateSteve99/KSP-B-Sides) (License: MIT) (Also has source code) by unzipping the folder and copying the contents of GameData to your installation's GameData folder.

A mod such as J2X antenna is also recommended as the stock antennas likely won't work when Eeloo is at apoapsis. Kerbal Joint Reinforcement is also recommended as rockets can get quite large.

Other legal stuff: Some code was taken from the Kittopia Dumps. As far as I can tell, the Kittopia Dumps license allows that, and I think that's all I need to say, if not, let me know.


This mod is not meant to be played in career mode, things will probably not work (some biomes may become inaccessible, etc). It is recommended to play in sandbox mode, but science mode is likely doable by increasing the rewards sliders.

Everything is balanced around an experienced player using stock + DLC parts. Every world is intended to be possible, though some of them get quite difficult.

I have playtested a bit, but I haven't tested everything. If you find a bug, or if you think something is balanced incorrectly, let me know! While each world is surmountable in a bubble, the sizes of the rockets necessary to launch them, even in pieces, may exceed reasonable limits. If that is the case, I will rebalance things.

Where are the C-sides?

The C-sides will be worked on once every B-side world has been conquered with stock+DLC parts. Visual and informational mods are allowed, MechJeb parts are allowed, bigger antennas are allowed, the only two physics mods allowed are BetterTimeWarpContinued and Kerbal Joint Reinforcement. If Eve, Jool, or Tylo end up being impossible, I will rebalance them to be more reasonable.


Let me know if you do anything cool in this mod, or if something is broken/way too hard!

Edited by Ultimate Steve
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31 minutes ago, wpetula said:

Does the low friction actually work on Eeloo? I've been trying to get that feature to work in Precursors for what feels like forever now.

I don't know,  actually. I felt it working but it could have just been placebo. I haven't done any rigorous testing on it, I'll add that to the list of things to do.

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