Difference between revisions of "Duna"
(→Atmosphere: Add a table of terminal velocities at 10 different altitudes.) 
(→Orbital Statistics) 

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The [[w:geosynchronous_orbitgeosynchronous orbit]] of Duna is at an altitude of  The [[w:geosynchronous_orbitgeosynchronous orbit]] of Duna is at an altitude of  
{{OrbitAltitude  period_s=65517.859375  mass_kg=4.51548115036107e21  radius_km=320 }} above Duna. The speed of the satellite is  {{OrbitAltitude  period_s=65517.859375  mass_kg=4.51548115036107e21  radius_km=320 }} above Duna. The speed of the satellite is  
−  {{OrbitVelocity  period_s=65517.859375  mass_kg=4.51548115036107e21  radius_km=320 }} and it has an orbital period resonating with 1 Duna day (18.2 hours or 65517.859375 seconds).  +  {{OrbitVelocity  period_s=65517.859375  mass_kg=4.51548115036107e21  radius_km=320 }} and it has an orbital period resonating with 1 Duna day (18.2 hours or 65517.859375 seconds). However, this orbit is not possible since it intersects with Ike's SOI. 
For a [[w:semisynchronous_orbitsemisynchronous orbit]] of ½ Duna day (9.025 hours or 32490 seconds) an orbit of  For a [[w:semisynchronous_orbitsemisynchronous orbit]] of ½ Duna day (9.025 hours or 32490 seconds) an orbit of 
Revision as of 18:53, 17 November 2012
Duna is the fourth planet of the Kerbol star system. It is the Mars analog for Kerbal Space Program and is mostly red with polar icecaps. It has one natural satellite, the moon Ike. Due to Ike's size and proximity, Ike and Duna are tidally locked to each other.
Contents
Topography
Duna is a ironrich planet which has greatly varying land altitude, the consequence of which is very difficult judgment of a safe landing position. Its mountainous ranges are a peril to landing craft, especially considering the thin atmosphere, where very little aerobraking can be done safely. It is important to slow one's ship down before coming into the atmosphere, to ensure a safe descent. There are several maria, or large regions of Dark soil at, exactly 0 meters altitude. These are ideal landing locations due to their low altitude, and thicker atmosphere for aerobraking. Its two poles are very expansive and are the result of a thin atmosphere. The central regions make a shape resembling Europe. 
Atmosphere
Duna's atmosphere begins at 41,446 m. It is only 20% as dense as Kerbin's at altitude 0 and is even less dense (relative to Kerbin) at higher altitudes. Like all atmospheres in the game, Duna's atmosphere fades exponentially with increasing altitude (with a scale height of 3000 m). In general, the atmospheric pressure on Duna at an altitude expressed in meters is:^{[1]} Parachutes work at lower efficiency than on Kerbin, making powered descent necessary when landing from orbit (unless your craft is a glider or just a pod with a parachute). The following table gives terminal velocities at different Duna altitudes. These are also the velocities at which a ship should travel for a fueloptimal ascent from Duna, given the game's model of atmospheric drag.^{[2]}

Orbital Statistics
The geosynchronous orbit of Duna is at an altitude of 0.00 m above Duna. The speed of the satellite is 0.00 m/s and it has an orbital period resonating with 1 Duna day (18.2 hours or 65517.859375 seconds). However, this orbit is not possible since it intersects with Ike's SOI.
For a semisynchronous orbit of ½ Duna day (9.025 hours or 32490 seconds) an orbit of 0.00 m above Duna is needed with a velocity of 0.00 m/s.
Reference Frames
Warp  5x, 10x  50x  100x  1000x  10,000x  100,000x 
Minimum Altitude  above atmosphere  60 km  100 km  300 km  600 km  800 km 
Gallery
 Duna projection.png
A false color Mercator projection of Duna's surface using MapSat.
Changes
 Initial Release
Notes
 ↑ A nuclear engine has a specific impulse of 220 in 1 atm, 800 in vacuum, and the following at various Duna altitudes:
altitude (m) 2 100 300 500 1460 2420 3000 4272 5000 10000 specific impulse 684.1 687.8 695.1 701.8 728.7 748.2 757.3 772.1 778.1 795.9  ↑ http://forum.kerbalspaceprogram.com/showthread.php/6664Minichallengemaxaltitudewiththissuppliedspacecraft?p=100912&viewfull=1#post100912