Jool

Jool in 0.17.

Jool is a gas giant and the fifth planet of the Kerbolar star system.

A probe visiting the gas giant.

Characteristics

• Equatorial Radius: 6000 km

• Mass: 4.236e24 kg

• Density: 4.68 g/cm³

• Surface Gravity: 7.84 m/s² (0.8 Gs)

• Gravitational parameter: 2.8254e14 m³/s²

• Escape velocity from surface: 9704 m/s

• Sidereal Rotation Period: ... hours; Rotation: ... degrees per hour, or ... m/s at the equator

• Solar Day: ... hours, or ... hours, ... seconds.

• Synchronous Orbit altitude: ... km; Stationary Orbit velocity: ... m/s

Orbital Characteristics

• Parent Body: Kerbol

• Semi-Major Axis: 6.87e10 m or 0.46 Astronomical Units (A.U.)

• Eccentricity: ...

• Inclination: 1.3°

• Velocity: ... m/s

• Longitude of Ascending Node: ...°

• Argument of Periapsis: ...°

• Mean Anomaly at Epoch UT = ...

• Orbital Period: ... hours, or ... Earth days

• Sphere of influence: 2,455,985 km, or 409 body radii.

Atmosphere

Aerobraking in Jool's atmosphere, with Laythe and Vall visible over the horizon.

Although Jool has a radius 10x bigger than Kerbin, its atmosphere only begins roughly twice as high (<138 km). It is also extremely dense, well suited for aerobraking from a high-speed inter-planetary intercept.

Closer to the surface, the physics of the game start to break down. Due to it's extremely thick atmosphere, terminal velocity is so low that lighter spacecraft will not even need parachutes or retrorockets. It is not impossible to land on it's solid (/liquid?) surface, though spacecraft are almost inevitably devoured by the Kraken.

Natural Satellites

Jool has four natural satellites:

The ocean moon Laythe, about to eclipse Jool.

• The ocean moon Laythe, which has an atmosphere and is both the largest and closest to Jool. Due to it's high orbital velocity, it is somewhat challenging to reach.

• The ice moon Vall, which is the second largest and second closest. It's orbital path and velocity sit almost exactly between Layth and Tylo.

• The rocky moon Tylo, similar to Kerbin's Mun, is the third body orbiting Jool. It is perhaps the easiest of the four to reach, with a stable orbit, large gravity well, and (relatively) slow orbital velocity.

• The captured asteroid Bop, the smallest body orbiting Jool. Due to it's distant, erratic orbit and low gravity, it is also challenging to reach.

Laythe, Vall, and Tylo are in a Laplace resonance, with orbital periods of 1:2:4 respectively.

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