Planet analysis: Atmospheres, gravity and environment.

This guide is made to explain and understand the environment of planets and moons and how the gravity and the atmospheres affect the thrusters. Knowing about this will help you in building your ships and to move around planets and moons.

General: Planets and moons

First, we will make a basic analysis of each planet:

Earth:

Based on our planet. It has a dense and thick atmosphere, with enough oxygen to breathe without oxygen supports.

• Bluish atmosphere, thin fog.
  
• Varied terrain.
  
• Multiple biomes: Ice poles, lakes, mountains, canyons, forests, deserts, etc.

Pros

• There are only a few lakes, but they suppose a great resource of ice.
  
• Breathable atmosphere.
  
• Atmosphere dense and thick, enough to make efficient the atmospheric vehicles.

Cons

• Strong gravity (1 G).
  
• Hard to leave the orbit due to the gravity and it's range.

Moon:

Based on our moon. It doesn't have atmosphere and considering the fact that the terrain is quite flat, it's a good place for mining operations and for ships propelled by ion thrusters.

• No atmosphere, no fog.
  
• Flat terrain except for the poles, which are very rugged, and some crater areas.
  
• We could consider 2 biomes: The 2 poles and the rest, which is a flat surface with some small hills and craters.

Pros

• Weak gravity (0.25 G).
  
• Very easy to leave the orbit.
  
• No atmosphere, which means that ion thrusters work at 100% (See how thrusters works at Thrusters section).
  
• The ice poles are a great resource of ice.

Cons

• No atmosphere, which means that atmospheric thrusters don't work.

Mars:

Based on Mars (Wow, really?). It has the thinnest and less dense atmosphere of all the planets. It's also smaller than Earth and Alien. The terrain is similar as the moon. It has a big pole, very flat and composed by a very thin layer of snow.

• Reddish atmosphere, no fog.
  
• Quite flat terrain, except some crater areas and small hills.
  
• We could consider 2 biomes: A big snow pole and the rest, which is a flat surface with some small hills and craters.

Pros

• The gravity is weaker compared with the other planets (0.90 G).
  
• Although the atmosphere is not very dense nor thick, the atmospheric vehicles will work (but worse than in other planets or moons).
  
• A bit easier to leave the orbit compared with the other planets.
  
• Flat terrain.

Cons

• The atmosphere is not very dense nor thick: The atmospheric vehicles don't work so efficient.
  
• The snow layer of the pole is not thick enough to be considered an efficient resource of ice.

Europa:

Based on the the sixth-closest moon of Jupiter, and the smallest of its four Galilean satellites. In Space engineers, Europa is the satelite of Mars. It's composed purely by snow and ice, except some stone traces and mineral deposits.

• Bluish atmosphere, very thin fog.
  
• Very flat terrain, except for a few fissures.
  
• We could consider that there is only one biome: Ice and ice and more ice...

Pros

• Weak gravity (0.25 G).
  
• The atmosphere is not very dense so the atmospheric vehicles will work very efficient (only close to the ground).
  
• Very easy to leave the orbit.
  
• Very flat terrain.
  
• Made entirely by ice, making this moon an almost infinite resource of ice.

Cons

• Although the atmosphere is very dense, it's also very thin: The atmospheric vehicles can't fly very high and may get lost in the void if they leave the atmosphere.

Alien:

The only fictional planet. It has the densest and thickest atmosphere and also the strongest gravity. It's also slightly bigger than the others. The atmosphere contains a small amount of oxygen, but not enough to breathe without oxygen support systems. It has flora and fauna (Both are fictional). There is presence of sabiroids. It could be considered the most hostile and adverse planet of all.

• Greenish atmosphere, thin fog.
  
• Very varied terrain.
  
• Multiple biomes: Ice poles and plains, desert, forest, high mountains, plains, lakes, etc.

Pros

• Dense and thick atmosphere, which makes atmospheric vehicles will work very efficient (best planet for atmospheric vehicles).
  
• Presence of lakes which makes a valuable resource of ice.
  
• Presence of oxygen in the atmosphere. This oxygen is not enough to be breathed directly, but using air vents with depressurize mode and oxygen tanks it's possible to refine the air.

Cons

• Presence of sabiroids.
  
• Strong gravity (1.10 G).
  
• Presence of sabiroids.

Titan:

Based on the largest moon of Saturn. Visually very similar to Mars, but with a dense and thin atmosphere, similar to Europa. There are also sabiroids like in Alien planet. Compared with other moons and planets, Titan has a very foggy atmosphere.

• Reddish atmosphere, relative dense fog.
  
• Flat terrain with some ice lakes.
  
• We could consider 2 biomes: Ice lakes and the rest.

Pros

• Weak gravity (0.25 G).
  
• The atmosphere is very dense so the atmospheric vehicles will work very efficient (only close to the ground).
  
• Very easy to leave the orbit.
  
• Flat terrain.
  
• Presence of thin ice lakes.

Cons

• Presence of sabiroids.
  
• Although the atmosphere is very dense, it's also very thin: The atmospheric vehicles can't fly very high and may get lost in the void if they abandon the atmosphere.

Atmospheres

Density and thickness.

First, we must distinguish two concepts: density and thickness.

• Density: The amount of gas per unit volume. Affects the maximum power of atmospheric thrusters.
  
• Thickness: Distance between the ground and the maximum altitude where there is still gas. Affects the maximum altitude (Also know as ceiling) of atmospheric thrusters.

A dense atmosphere does not implies a thick atmosphere. The density affects the thrust power while the thickness affects the maximum altitude.
For example, Europa's atmosphere at 0 meters from the ground is very dense compared with other planets and moons, but at 860 meters there is no atmosphere, while Mars has a less dense atmosphere at 0 meters but the atmosphere lasts to 6900 meters from the ground.

The following table shows thickness of the current atmospheres.

Planet	Thickness (Expressed in meters)
Earth	8900
Moon	No atmosphere
Mars	6900
Europa	860
Alien	8900
Titan	670

Sadly, there are no specific ways to measure the density of an atmosphere, but it can be estimated by the power of Atmospheric Thrusters.

This table shows roughly the characteristics of the atmospheres.

Planet	Characteristics
Earth	Dense and thick
Moon	No atmosphere
Mars	Thin
Europa	Very dense, very thin
Alien	Very dense, thick
Titan	Very dense, very thin

Oxygen presence

Also, note that the presence of atmosphere does not implies oxygen. Like in real life, atmospheres are composed by gases, but not necessarily contain oxygen.

The following table shows the oxygen presence in planets:

Planet	Oxygen amount
Earth	High
Moon	None
Mars	None
Europa	None
Alien	Low
Titan	None

So far the only planet who has breathable atmosphere is the Earth. The Alien planet has a low density of oxygen but is not possible to breathe without oxygen support systems. But an oxygen system can retrieve oxygen from the atmosphere and fill oxygen tanks.



This is a basic oxygen extractor: 3 air vents, 1 oxygen generator, 2 oxygen tanks and a power supply.
The air vents must be set to Depressurize. This will act like if they extract oxygen from a pressurized room with an infinite amount of oxygen. So basically, this system will extract the oxygen in the atmosphere and fill the oxygen tanks.

Gravity

The natural gravity of planets and moons will attract our ships to them. It's good to know about this because understanding this behavior will help us to control our ships, go out of orbit and more.

Maximum gravity strength

First let's see the maximum gravity of each of the planets and moons:

Planet	Gravity (Expressed in G)
Earth	1
Moon	0.25
Mars	0.90
Europa	0.25
Alien	1.10
Titan	0.25

As you can see, all the moons have a weak gravity (0.25).

Maximum gravity range

Now, let's see the maximum range of the gravity. This is basically the distance from the ground where the ships and other objects won't be affected by the gravity.

Planet	Maximum gravity range (Expressed in meters)
Earth	41800
Moon	2900
Mars	38500
Europa	3200
Alien	42700
Titan	3000

This values are very rounded and they are not very precise. May vary 100 meters or more.

Gravity decrease range

Finally, there is the range where the gravity starts decreasing. You should know that once reached the gravity decrease range, the gravity starts decreasing very quickly but then the decreasing rate reduces. There is an inverse exponential decrease.

Planet	Gravity decrease range (Expressed in meters)
Earth	6000
Moon	400
Mars	4100
Europa	670
Alien	5650
Titan	590

This information may be useful for the following:

• Knowing the maximum gravity range, you can build a static station close to a planet.
  
• When taking off from a planet, once reached the gravity decrease range, you can start reducing the thrust of the ship to save fuel and energy.
  
• Knowing the gravity strength is important when you are moving heavy objects around a planet.

Thrusters

In this section I will explain how thrusters are affected by the atmosphere. It's important to know this when you build your ships, because the planets and moons are very different from each other and you will need specific configurations.

There are 3 thruster types:

Hydrogen Thruster

The most powerful. Requires a more complex system to work (Hydrogen tanks and conveyors) and uses hydrogen instead of electricity like the other 2. It is the best choice if you are going to build a ship such a shuttle that needs strong thrust to leave the orbit, a heavy planetary transport ship or you just want a fast and maneuverable ship. The thrust power is not affected by anything, which means that the power is the same in any environment.

Values expressed in KN. The values are the highest achievable thrust power.

Environment	Small ship, Small Thruster	Small ship, Large Thruster	Large ship, Small Thruster	Large ship, Large Thruster
Any	82	400	900	6000

Ion Thruster

The classic thruster. Works at 100 % in the void, but the power is reduced by the atmospheres. Note that the power is reduced by the atmospheric density, not by the gravity. The more dense is the atmosphere, more reduced is the power.

Values expressed in KN. The values are taken from the ground (altitude 0), considering the point where the atmosphere is more dense. The values are the highest achievable thrust power.

Environment	Small ship, Small Thruster	Small ship, Large Thruster	Large ship, Small Thruster	Large ship, Large Thruster
Void	12	144	288	3600
Earth	4	52	104	1300
Moon	12	144	288	3600
Mars	5	66	131	1600
Europa	4	43	86	1100
Alien	4	43	86	1100
Titan	4	43	86	1100

Atmospheric Thruster

This thruster only works on atmospheric environments, and the more dense is the atmosphere, more powerful is the thruster. With no atmosphere, the thrust power is 0.

Values expressed in KN. The values are taken from the ground (altitude 0), considering the point where the atmosphere is more dense. The values are the highest achievable thrust power.

Environment	Small ship, Small Thruster	Small ship, Large Thruster	Large ship, Small Thruster	Large ship, Large Thruster
Void	0	0	0	0
Earth	70	357	367	4700
Moon	0	0	0	0
Mars	54	278	286	3700
Europa	80	408	420	5400
Alien	80	408	420	5400
Titan	80	408	420	5400

Final conclusions and recomendations

So, knowing this, we can say the following:

Note that the hydrogen thruster will work better than anything else and always at the same power, but requires a more complex system and the capacity of the fuel is more limited compared with the other thrusters

• Earth: The best way to move around this planet is by using atmospheric thrusters and ground vehicles. The ion thrusters don't generate enough thrust to keep a ship floating, but they can be used for a little thrust at laterals.
  
• Moon: Atmospheric thrusters don't work, but the ion thrusters work at 100 % due to the absence of atmosphere. Still be aware that there's still a small attraction by the gravity. Also, take in mind that due the weak gravity, the ground vehicles will not stick on the ground like in the planets.
  
• Mars: The ion thrusters are discarded at least for keeping the vehicles floating, but they work a little better than in the Earth. The ground vehicles work fine and atmospheric vehicles work enough efficient, but worse than in any other planet or moon.
  
• Europa: Like in the Moon, keep in mind the that gravity is weak, but unlike the Moon, Europa has atmosphere. The atmosphere is very dense but also very thin. The atmospheric vehicles work very efficient close to the ground but due to weak gravity and the thickness, you could go out of orbit with an atmospheric vehicle, and lose it into the void.
  
• Alien: The ground vehicles work fine like in the other 2 planets. The atmospheric vehicles work better than in any other planet or moon because the atmosphere is thick and dense and they will have strong thrust power and high ceiling. The ion thrusters are not recommended at all.
  
• Titan: This moon is basically the same as Europa, but the atmosphere is even more thin.

[infra-dan-accelerator unit 84725]

u missed petram and trition. for those who are wondering,trition is another ice-heavy planet based on the biggest moon of neptune. oxygen level is low and temprature is freaze. the weather is snow snow and more snow...biomes:ICEY. i dont remember the gravity or the atmosvere. and has wolves. (i think)

[A strange sphere]

What are the sabiroids? Are they the spiders?

[ryeomau]

Alien and Titan has them neat spooders

[eater of bees]

pertam and triton?

[ryeomau]

Pertam has been added, might be worthwhile

[DonCall]

Only the informations about Triton is missing. Than it would be the best Guide in Web

[TheDevBird]

You said that there is an inverse exponential decrease of the gravity. What factor (b)?
y=9.8(1-b)^x

[Anubis 1101]

wonderful and thorough guide! i started on the moon and had no idea the rest of it was flat.

ive been launching hundreds of meters in the air with my little moon rover, but i may consider moving to the border between the two biomes..

[Onikage-056, God of Animatronics]

Sidenote about Titan: If you're not careful, you can make orbit just bouncing off the terrain at high speed... assuming the impact doesn't plaster you across the landscape.

[aaueer]

This is really helpful since there is basically no official in-game information on atmosphere