View source for Duna

{{Infobox celestial body}}
Duna  is a small, dry planet that is the fourth planet in the [[Kerbolar system]] and functions as a Mars analog. Its orbital eccentricity and inclination are similar to [[Kerbin|Kerbin's]] making it a relatively easy destination for interplanetary ships to reach from Kerbin. It features a thin atmosphere and a relatively massive moons moon [[Ike]]. 

== Synopsis ==
''Duna, the reddest planet, has long been an object of study and inspiration to Kerbal scientists and artists alike. Its thin low-pressure atmosphere allows for both aerobraking and relatively easy access to its surface. Kerbal researches and sci-fi writers often discuss the discoveries that could be waiting for them in the planet's polar ice caps or on Duna's tidally locked moon Ike.''

== Surface ==
Duna has a desert-like reddish colored surface composed primarily of silicate rocks and sands, covered by a fine layer of dust up to a few millimeters thick. This dust layer is theorized to be the result of dust storms. Dunian soil contains nutrients such as [[wikipedia:Sodium|sodium]], [[wikipedia:Potassium_chloride|potassium chloride]] and [[wikipedia:Magnesium|magnesium]]. The planet exhibits no tectonic activity and is believed to be geologically dead. Evidence of past tectonic activity is present however, with volcanic basalt being quite common in certain regions. Surface features and exposed rocks show heavy signs of erosion by wind as well as flowing water. This combined with a the surprising amount salt in the ground indicates that Duna's surface may once have held liquid water. Duna's surface topography is mostly flat with occasional mountains and dunes. Various [[wikipedia:Impact_crater|impact craters]] are spread out over its surface area. The majority of these are simple bowl-shaped craters with sparse [[wikipedia:Complex_crater#Central-peak_craters|center peak]] and [[wikipedia:Peak_ring|peak ring]] formations. These craters are often eroded by the elements and overall less pronounced than those on atmosphere-less celestial bodies. For an unknown reason the northern hemisphere has significantly more impact craters. This may be explained by the impact of a comet that shattered before reaching the surface. 

=== Polar ice caps ===
The most northernmost and southernmost parts of Duna's surface are covered by [[wikipedia:Polar_ice_cap|polar ice caps]]. These ice caps start at roughly 65 and -70 latitude respectively. They are estimated to be about 5 kilometers thick at their deepest point and composed of water ice and snow with a thin top layer of frozen carbon dioxide and trace amounts of dust. The northern ice cap has a deep spiraling pattern of troughs. These troughs are caused by roughly perpendicular [[wikipedia:Katabatic_wind|katabatic winds]] that spiral due to the [[wikipedia:Coriolis_force|coriolis effect]]. 

== Atmosphere ==
Duna has a thin cool atmosphere with a depth of 50,000 meters. Compared to the atmosphere of Kerbin, Duna's atmosphere has 1/15th the mass, 1/15th the surface pressure and 1/9th the surface density. Duna's atmosphere is predominantly composed of [[wikipedia:Carbon_dioxide|carbon dioxide]] with a small fraction of [[wikipedia:Nitrogen#:~:text=Nitrogen%20is%20a%20chemical%20element,Way%20and%20the%20Solar%20System.|nitrogen]] and [[wikipedia:Argon|argon]] as well as traces of oxygen, carbon monoxide, water, methane, and other gasses. Melting of snow in the polar regions due to seasonal temperature variations is believed to be responsible for Duna's thin wispy clouds. These clouds are then carried toward the equator by a polar [[wikipedia:Jet_stream|jet stream]]. 

=== Atmospheric flight ===
The thickness of Duna's atmosphere makes it suitable for aerocapture from a high-speed interplanetary intercepts. Although parachutes will deploy on Duna, the atmosphere is so thin that they are usually unable to slow a craft to a safe landing velocity and must be assisted with engines. Parachute performance can be particularly troubling when attempting to land in the highland areas. Below 5,000 meters Duna's atmosphere is thick enough to allow wings to generate enough lift for aerodynamic flight. Jet engines will not work on Duna due to a lack of oxygen in the atmosphere, but other propulsion methods work well. Performing a horizontal landing with a plane is also possible. 

=== Magnetosphere ===
Duna has a weak magnetic field that's about 2% the strength of Kerbin's. There is evidence that Duna once had a much more powerful magnetic field, but it weakened overtime as its core cooled. 

== Science regions ==
Duna has 6 surface regions which makes it one of the most region-rich bodies second only to Kerbin and [[Laythe]]. It is an ideal place for science collection for players who are embarking on their first interplanetary journey. 
{| class="wikitable"
|+Orbital situations
!Science region
!Altitude range (m)
!Science multiplier
|-
|High Orbit
|> 70,000
|16.0
|-
|Low Orbit
|50,000 - 70,000
|24.0
|-
|Atmosphere
|< 50,000
|8.0
|}
{| class="wikitable"
|+Surface regions
!Science region
!Science multiplier
|-
|Highlands
|20.0
|-
|Midlands
|20.0
|-
|Lowlands
|20.0
|-
|Polar deserts
|20.0
|-
|North pole
|20.0
|-
|South pole
|20.0
|}

== Discoverables ==
Duna face it, there's nothing here yet 

== Version history ==
[[0.2.0.0]] 

* Added science regions.

[[0.1.5.0]] 

* Updated atmospheric scattering.

[[0.1.2.0]] 

* Celestial body ground scatter updates.

* Height fog added.

[[0.1.0.0]] 

* Initial release.

[[Category:Planets]]