Nero as seen from orbit.
[[Nero/Param|Nero/Param]] of [[Nero/Param]]
Orbital Characteristics
Semi-major axis  m [Note 1]
Apoapsis  m [Note 1]
Periapsis  m [Note 1]
Orbital eccentricity Expression error: Unrecognised punctuation character "[".
Orbital inclination Expression error: Unrecognised punctuation character "[". °
Argument of periapsis Nero/Param °
Longitude of the ascending node Nero/Param °
Mean anomaly Expression error: Unrecognised punctuation character "[". rad (at 0s UT)
Sidereal orbital period  s
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Synodic orbital period Expression error: Unexpected < operator. s
Orbital Velocity to  m/s
Physical Characteristics
Equatorial radius  m
Equatorial Circumference  m
Surface area Expression error: Unexpected < operator. m2
Mass Expression error: Unexpected < operator. kg
Standard gravitational parameter Expression error: Unexpected < operator. m3/s2
Density Expression error: Unexpected < operator. kg/m3
Surface gravity Expression error: Unexpected < operator. m/s2 (Expression error: Unrecognised punctuation character "[". g)
Escape velocity  m/s
Sidereal rotation period Expression error: Unrecognised punctuation character "[". s
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Sidereal rotational velocity Expression error: Unexpected < operator. m/s
Synchronous orbit  km
Sphere of influence Expression error: Unexpected < operator. m [Note 1]
Atmospheric Characteristics
Atmosphere present Expression error: Unrecognised punctuation character "[".

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Scientific multiplier
Surface Nero/Param
Splashed Nero/Param

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Near space Nero/Param
Outer space Nero/Param
Recovery Nero/Param

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

Nero is the largest planet in the Ciro system and a member of the Galilean planets. It is the 9th planet in distance from Ciro, and the farthest of the three gas giant planets. Nero has four moons – Hadrian, Narisse, Muse, and Minona. It not only stands above the other planets as the largest of them all, but also as one of the two founding planets in Galileo's Planet Pack.

Nero's orbit is slightly larger than that of Urlum and its sphere of influence has at least 4x the radius of Jool's, making room for several additional moons if they were to possibly happen.

In-game description

"Rightfully named, this planet kommands the stellar kourt and wears his rings slanted for all to behold. Some kerbals have gathered under a belief that a Heaven exists in his domain, filled with snacks that no corporeal kerbal can reach or fathom."
- Deep Sky Press

Physical Characteristics

Nero is the solar system’s largest planet, having a mass approximately twice that of Otho and four times that of Gauss. In comparison to Gael, it has about eight times the radius and 67 times the mass. If scaled up to life-sized proportions, Nero would have about 2 times the radius and 3.5 times the mass of the planet Neptune. Although Nero is king among planets in the Ciro system, it would have less than 1/5th the mass of Jupiter.

Nero’s equator is inclined 10 degrees to the ecliptic plane. The planet has a very rapid axial precession with a period of 11 hours, the same as its rotation period. In real life such a rapid precession could not exist, but it was implemented by the mod developers because of its interesting visual effect.


Nero’s atmosphere consists predominately of hydrogen (81%), with some helium (9%) and other gases. The datum that defines Nero’s “surface” is the altitude at which the atmospheric pressure is 15 atmospheres.

The top of Nero’s atmosphere lies 560 km above the datum. Here the temperature averages -124°C. Descending through the atmosphere, the temperature decreases while the pressure rises exponentially. The temperature reaches a minimum of about -208°C at the 0.1 atm level (210 km altitude). Below this level the temperature steadily increases due to internal heating. At the 1 atm level (153 km) the temperature is -171°C. This increases to -1°C (272 K) at the datum. Although Nero is farthest from the sun, its datum temperature is the highest of the three gas giants because it generates the most internal heat.

Nero’s upper atmosphere experiences some small latitudinal, diurnal, and seasonal temperature variations. These variations are greatest at the upper boundary, where temperature can range by as much as 13°C. The temperature variations cease at altitudes below the 1 atm level.


Nero is one of two planets having a ring system, the other is Tellumo. Nero’s rings have a very complex structure, consisting of many individual light and dark rings, interspersed with gaps apparently devoid of ring material. The rings extend from about 1,400 km to 7,400 km above Nero’s equator. The rings have the same rapid precession rate as the planet’s rotational axis, thus the rings remains coplanar with Nero’s equator.

Flight Performance

To be added.


Nero has 5 natural biomes:

  • Sashed Storms Regalia
  • Northern Storms Province
  • Southern Storms Province
  • North-most
  • South-most

Gameplay features

  • Nero’s cloud bands have differential rotation, made possible by the optional plugin Stock Visual Enhancements. With this installed and some generous time warp the animation becomes very clear.
  • Any craft that descends to an altitude of -250 meters instantly implodes.
  • The rings are intangible and by themselves offer no solid benefit or threat. However, some resources can be found within them and nowhere else in space within this planet's SOI. Between the gas giants and space Karbonite, Nero is the most selfish.


  • In real life, the 1 bar (≈1 atm) pressure level is usually used to define the datum for gas planets.
  • As the local king of planets, there is no more appropriate of a name for it than Nero.


Nero has two associated flags. The first of which is its region flag, The House of Nero, and the second is the Three Kings challenge flag, by which any vessel that wears it is bound exclusively to visit all of the gas planets and all of their moons. Entering other SOI except Gael's is prohibited.