The fifth moon orbiting Cyran is Sennim, the largest of the six moons in orbit around the giant planet.

PlanetCyran Sennim

In-Game description

"A world with a dense atmosphere and lakes of mercury, this world bears a striking resemblance to Kerbin, yet at the same time is nothing like it. A bit like Eve, only less hard to land and return from. And this planet looks strangely green... perhaps it's vegetation? Only one way to find out..."


Physical properties

Sennim has a radius equal to that of Laythe, although it's surface gravity is slightly lower, indicating that the moon is less dense. It's radius is 1 Laythe radii or 0.833 Kerbin radii while it's surface gravity is 1.2g. Like Laythe, Sennim is tidally locked. Unlike Laythe, however, Sennim has lakes instead of oceans, the surface is mainly land. Sennim has oceans of liquid Mercury though instead of water.


Sennim has a dense atmosphere that is rich in Chlorine and Hydrogen. Although Sennim is smaller than Kerbin and has a lower gravity, it has an atmospheric pressure of 1.2 times that of Kerbin, therefore parachutes and wings are very effective when trying to land.


Sennim has six biomes in total, and these are:

  • Poles (white)
  • Lakes (blue)
  • Highlands (Red)
  • Midlands (Green)
  • Lowlands (Black)
  • Polar Lakes (Yellow)


Quote from the author of the Planet Cyran mod:

“With Sennim I wanted to to something very different: create a world with extra-terrestrial life. I quickly got the idea of giving it silver oceans of Mercury, a metal that is liquid at room temperatures. After some in-game experimenting with VertexPlanet I actually managed to pull it off. I also made various textures for both the surfaces of the planets, the oceans, and even the terrain scatter in Sennim's case. I actually planned on giving Sennim a sandy golden atmosphere, but whilst editing the atmosphere in-game with KittopiaTech I accidentally gave it a green color instead of golden. I actually liked the green color, so I saved that color in the config file, then made a screenshot and isolated the color using an image editing program so I could use it for the ambient color and rim color. It's funny how I then forgot about this change and accidentally gave Sennim a golden atmosphere in every image despite having given it a green atmosphere.”


  • Sennim is the only Kopernicus planet thus far that features custom trees, or trees in general.
  • Sennim is one of the few Kopernicus planets to feature custom ocean and surface textures.

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