Gratian is the 6th planet in the Ciro system and a member of the Galilean Planets.  It is the third largest of the rocky planets, and the sixth largest overall.  It is the planet closest to Gael in terms of size and mass.  Gratian is the most distant of the inner planets, with the region beyond its orbit being the domain of the gas giants.

Gratian has a superficial similarity to the real life planet Mars, and to the stock planet Duna; however, there are several key differences.  Gratian is larger, has a higher surface gravity, has a thicker atmosphere, receives less sunlight, and is much colder.

Gratian has a very large and nearby moon, Geminus.  Both bodies are tidally locked to the other.  They are not considered a binary system, however, because the barycenter lies below Gratian’s surface.

In-game description

"In decades past, a poetically inclined kerbal, close friends with a chef, often had dreams of a world filled with spicy food. These dreams inspired highly eccentric stories that were hidden until his passing. One of these even went as far as to say something about controlling this spice and the universe. Maybe he was onto something..."
- Deep Sky Press


Gratian has more surface area of exposed soil and rock than any other body in the solar system, with all larger bodies being either gaseous or having surfaces covered in large part by water and/or ice.  On Gratian the traditional lowlands, midlands and highland biomes go by the more tasty sounding names of Inverse Gratin, Infinite Paprika, and Cinnamon Heights.  The Infinite Paprika biome covers half the planet’s surface area.  Gratian’s highest mountains peaks are found in the Turmeric Ridge and Ribbed Dunes biomes.  Among the inner rocky planets, Gratian’s surface has the least amount of relief, with about 6,000 meters separating its lowest and highest points.  The mean ground elevation is approximately 2,900 meters.  The planet has large ice caps that cover about 10% of its surface.


Gratian has a thick, cold atmosphere consisting principally of nitrogen (88%).  The air pressure ranges from 0.5 to 0.14 atmospheres between Gratian’s lowest and highest surface elevations.  The air temperature decreases with increasing altitude, reaching a minimum at an altitude of about 35 km, before increasing toward the upper boundary.  There are isothermal layers at around 16 km, where the temperature is -142°C, and at 36.5 km, where the temperature is -148°C.  The upper boundary is found at an altitude of 50 km.


Gratian’s surface is very cold with a mean datum level temperature of -116°C (157 K).  Because temperature decreases by about 1.5°C for every kilometer rise in elevation, the actual temperature averaged across all points on Gratian’s surface is about -121°C.  The mean temperature at the equator is about -116°C, and at the poles it is -140°C.  The diurnal variation is about 9°C at the equator and 3°C near the poles.  Gratian has a seasonal variation of about 7°C, which is due in most part to the planet’s eccentric orbit.  Gratian’s weather includes frequent dust storms.

Flight Performance

To be added.


Gratian has 9 natural biomes:

  • Inverse Gratin
  • Infinite Paprika
  • Cinnamon Heights
  • Major Varicose
  • Minor Varicose
  • Lean Dunes
  • Ribbed Dunes
  • Turmeric Ridge
  • White Spice

Gameplay Features

  • Gratian has animated dust storms, made possible by the optional plugin Stock Visual Enhancements. This enables the fun and in some cases, challenges of landing and operating within a sandstorm.


  • Gratian was originally envisioned as the most prominently featured planet in the GPP solar system, but as the mod developed and Gael appeared, Gratian lost its promised glamour.


Gratian and its moon Geminus share just one region flag, the Grat & Gem/ G&G. Gratian is also a Border-world due to being the outermost of the inner rocky planets.

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