Priax as seen from orbit.
Moon of Urlum
Orbital Characteristics
Semi-major axis 11 727 895 m [Note 1]
Apoapsis 11 745 487 m [Note 1]
Periapsis 11 710 303 m [Note 1]
Orbital eccentricity 0.002
Orbital inclination 2.5 °
Argument of periapsis 0 °
Longitude of the ascending node 40 °
Mean anomaly 1.521 rad (at 0s UT)
Sidereal orbital period 73 017 s
3 d 2 h 16 m 57.1 s
Synodic orbital period 73024.3 s
Orbital Velocity 1 008 to 1 011 m/s
Longest Time Eclipsed 4346 s
Physical Characteristics
Equatorial radius 74 000 m
Equatorial Circumference 464 956 m
Surface area 6.8813445×1010 m2
Mass 5.0691280×1019 kg
Standard gravitational parameter 3.3831766×109 m3/s2
Density 29 864.104 kg/m3
Surface gravity 0.618 m/s2 (0.063 g)
Escape velocity 302.39 m/s
Sidereal rotation period 73 017.111 s
3 d 2 h 16 m 57.1 s
Sidereal rotational velocity 6.3678 m/s
Synchronous orbit 696.20 km
Sphere of influence 446 767.60 m [Note 1]
Atmospheric Characteristics
Atmosphere present × No
Scientific multiplier
Surface 13
Splashed N/A
Near space 10
Outer space 9
Recovery 9

  1. 1.0 1.1 1.2 1.3 The distances are given from the bodies center not surface (unlike ingame)

Priax is a moon of Urlum, and shares its orbit with Polta.

In-Game Description

Priax shares the orbit of its larger cousin Polta, making it a co-orbital configuration. This strange orbit is stable because Priax is located in the libration point of the larger Polta. Priax is also characterized by its heavily cratered surface, which makes it sort of resemble lump of cheese. Whether the surface is edible has yet to be confirmed.

Kerbal Astronomical Society

Physical Properties

Priax has a heavily-cratered surface and an extremely low density. These indicate that it is likely a captured asteroid, which is somewhat unexpected so far out in the solar system.

While the density values do not correlate with any real-life materials, as they can with the other planets and moons in the game, they do correlate to the average density of other asteroids in-game, which when taken in context with the KSP Universe, indicates it is indeed a captured asteroid.


It is interesting to note that Priax shares an orbit with Polta around Urlum. These co-orbiting moons are called trojan moons. This unique moon system is stable because Priax sits at Polta's L5 Lagrangian point, meaning their gravitational forces are perfectly balanced with the orbit, therefore keeping them from colliding. Polta and Priax are the only trojan moons in the game.


Priax has a total of 5 biomes.

Biome list

Priax Biome Map

Priax biome map

  • Badie Region
  • Leading Craters
  • Sido Region
  • Trailing Craters
  • Crater Chains

Reference Frames

Warp Minimum Altitude
5× 4 163 m
10× 8 325 m
50× 16 650 m
100× 33 300 m
1 000× 66 600 m
10 000× 133 200 m
100 000× 266 400 m