Complete Guide to the Kerbol System (1.12, stock + OPM)

Accurate as of 1.12.2. Now with at least 100% extra OPM!

Kerbol

Kerbol as seen from orbit.
Physical Properties
Radius: 261,600 km
ASL Gravity: 1.74 g
Escape Velocity: 94672 m/s
Has Atmosphere: Yes
Atmospheric Properties
Height: 600 km
ASL Pressure: 0.15 atm
ASL Temperature: 5840 K
Contains Oxygen: No

Kerbol (known ingame as The Sun) is the only star in the stock game, and it is the analog for the sun. Due to its extreme temperature, it is impossible to land on Kerbol, even with the use of cheats; the craft will be destroyed.

All of the planets and dwarf planets in this guide orbit it, and it does not orbit anything else.

Moho

Moho as seen from orbit.
Physical Properties
Radius: 250 km
ASL Gravity: 0.27 g
Escape Velocity: 1161.4 m/s
Has Atmosphere: No

Moho is the first and closest planet to Kerbol. It is the Mercury analog for KSP. Moho is arguably the hardest planet to get to and return from; because you will be encountering at approximately 8 km/s from a Hohmann transfer, and since it lacks an atmosphere (which means that above other things, you can't aerobrake), a mission to Moho will use a lot of its total delta V slowing down into orbit.

It is similar to the Mun but is larger and has higher gravity. Its surface is quite rough, so it's not recommended to send a spaceplane to Moho (if you do, consider making it STOL (short takeoff and landing)).

Eve System

Eve

Eve as seen from orbit.
Physical Properties
Radius: 700 km
ASL Gravity: 1.7 g
Escape Velocity: 4832 m/s
Has Atmosphere: Yes
Atmospheric Properties
Height: 90 km
ASL Pressure: 5 atm
ASL Temperature: 408 k
Contains Oxygen: No

Eve is the largest planet in the inner system, being even bigger than Kerbin. It is a somewhat buffed Venus analog. Eve is popularly referred to as the "final boss" of KSP due to its difficulty: despite it being the closest planet to Kerbin, closer than even Duna, it is extremely hard to return from due to the thick atmosphere and huge gravity well. Getting into low orbit of Eve from sea level requires about 7000 m/s of delta V. Aerobraking is also very risky: because of the atmosphere's thickness, a craft will often lose control and break apart if it goes too low.

Its surface is covered in large oceans of a purple liquid known as Explodium. It is very possible that, like on Earth with the water cycle, there likely is some kind of Explodium cycle on Eve. It has one tiny moon named Gilly.

Gilly

Gilly as seen from orbit.
Physical Properties
Radius: 13 km
ASL Gravity: 0.005 g
Escape Velocity: 35.7 m/s
Has Atmosphere: No

Gilly is the sole moon of Eve, and it is a tiny captured asteroid in a highly elliptical and inclined orbit. It holds the distinction of being the smallest celestial body in the stock game. (However, with OPM, Hale is actually smaller, being just under half the size of Gilly.)

Kerbin System

Kerbin

Kerbin as seen from orbit.
Physical Properties
Radius: 600 km
ASL Gravity: 1 g
Escape Velocity: 3430.4 m/s
Has Atmosphere: Yes
Atmospheric Properties
Height: 70 km
ASL Pressure: 1 atm
ASL Temperature: 288 k
Contains Oxygen: Yes

Kerbin is the third planet from Kerbol and is the homeworld of the Kerbals. This is reflected by the fact that all of the launch locations (Woomerang, Dessert, KSC, and discoverable) are located on Kerbin. It is the Earth analog for KSP. Kerbin is covered in vast oceans of liquid water, with some grassy fields and tall mountains covering the landmasses.

Getting into a stable orbit of Kerbin requires about 3500 m/s of delta V. This is the first accomplishment of any fledgling space program, as once you're in orbit, you're pretty much halfway to anywhere. It has two moons named the Mun and Minmus.

Mun

The Mun as seen from orbit.
Physical Properties
Radius: 200 km
ASL Gravity: 0.16 g
Escape Velocity: 807 m/s
Has Atmosphere: No

The Mun (also spelled as Mün) is the closest celestial body to Kerbin, and is the analog for Earth's Moon. In a career game, the Mun will usually be the first other body you land on besides Kerbin. However, many players (myself included) will often go to Minmus instead. Its surface is gray and rocky. Landing on the Mun is fairly easy, although it can be somewhat difficult if you're attempting to design a small lander.

Minmus

Minmus as seen from orbit, with Kerbin and the Mun in the background.
Physical Properties
Radius: 60 km
ASL Gravity: 0.05 g
Escape Velocity: 242.6 m/s
Has Atmosphere: No

Minmus is the smaller and more distant of Kerbin's two moons. Its surface is quite lumpy, but does have some large flats regions which make ideal landing spots. After the Mun, Minmus will usually be the first body you'll send a mission to in career mode.

Duna System

Duna

Duna as seen from orbit, with Ike in the background.
Physical Properties
Radius: 320 km
ASL Gravity: 0.3 g
Escape Velocity: 1372.4 m/s
Has Atmosphere: Yes
Atmospheric Properties
Height: 50 km
ASL Pressure: 0.0667 atm
ASL Temperature: 250 k
Contains Oxygen: No

Duna is the outermost of the inner planets, and is the smallest body in the stock game with an atmosphere. It is the analog for Mars. Getting to Duna is fairly easy compared to other planets, as it is close and its orbit is not very inclined, despite being quite eccentric. It is well known for its very reddish-orange color. Its thin atmosphere can still be used for aerobraking, although you will need to go deeper for it to be effective. Heat shields are not required, as Duna reentry speed is well under its supersonic speed.

It has one moon named Ike.

Ike

Ike as seen from orbit, with Duna in the background.
Physical Properties
Radius: 130 km
ASL Gravity: 0.11 g
Escape Velocity: 534.5 m/s
Has Atmosphere: No

Ike is the only moon of Duna. It is a somewhat lumpy rock quite large compared to its planet. Duna and Ike form somewhat of a double planet similar to real life Pluto and Charon. Ike is famous for being the home of the Magic Boulder, which is an easter egg located on its surface. Formerly, the Boulder used to orbit Ike, but it was removed and then readded.

Dres

Dres as seen from orbit.
Physical Properties
Radius: 138 km
ASL Gravity: 0.11 g
Escape Velocity: 558 m/s
Has Atmosphere: No

Dres is the first dwarf planet orbiting Kerbol, and it is the analog for Ceres. There isn't really much to do at Dres, with the exception being finding a ton of asteroids (a.k.a. Dresteroids) orbiting Dres. There is a known meme that Dres is boring/doesn't exist. However, I can confirm to you that Dres does in fact exist, and you can land on it to prove that.

Jool System

Jool

Jool as seen from orbit.
Physical Properties
Radius: 6000 km
ASL Gravity: 0.8 g
Escape Velocity: 9704.4 m/s
Has Atmosphere: Yes
Atmospheric Properties
Height: 200 km
ASL Pressure: 15 atm
ASL Temperature: 200 k
Contains Oxygen: No

Jool is a very large and green gas giant, and is the largest planet in the entire system, being ten times bigger than Kerbin. It is the Jupiter analog for KSP, although it seems to have more Saturn-like characteristics. As it is a gas giant, you cannot land on it: craft will clip through the surface until reaching an altitude of -250 m, at which they will explode. Despite that, it still is an attractive target for missions because of its rich system of five moons: Laythe, Vall, Tylo, Bop and Pol.

With SVE Jool has a thin system of rings that are just barely visible in the image above.

Laythe

Laythe as seen from orbit.
Physical Properties
Radius: 500 km
ASL Gravity: 0.8 g
Escape Velocity: 2801.4 m/s
Has Atmosphere: Yes
Atmospheric Properties
Height: 50 km
ASL Pressure: 0.6 atm
ASL Temperature: 282 k
Contains Oxygen: Yes

Laythe is a large and wet moon of Jool that is the innermost of its three major moons. Laythe is unique for the fact that it has an oxygen atmosphere, which means kerbals can take off their helmets and jet engines will function. It is quite large, meaning that reaching orbit can be difficult; a 60 km orbit around Laythe takes about 2000 m/s to reach from sea level. However, the atmosphere can significantly reduce your delta V requirement as you can aerobrake and use parachutes effectively.

Laythe is an example of a tidally heated habitable moon; one that maintains Earthlike climate through internal heat from its gas giant parent. However, Jool's mass is not enough to sustain that on its own: the rest must be from the atmospheric greenhouse effect. With the presence of oxygen it is very possible that Laythe has life.

Vall

Vall as seen from orbit, with Jool in the background.
Physical Properties
Radius: 300 km
ASL Gravity: 0.23 g
Escape Velocity: 1176.1 m/s
Has Atmosphere: No

Vall is the smallest and often the most overlooked of Jool's major moons. But alas, it is the easiest of the three to land on because its gravity is only slightly greater than that of the Mun. Vall's surface is quite rough and is covered in ice volcanoes if you have the Breaking Ground DLC installed.

Tylo

Tylo as seen from orbit, with Jool and Laythe in the background.
Physical Properties
Radius: 600 km
ASL Gravity: 0.8 g
Escape Velocity: 3068.8 m/s
Has Atmosphere: No

Tylo is a huge moon without an atmosphere, and the analog for Ganymede. It is the same size as Kerbin, although its gravity is weaker, indicating it must be less massive. Tylo can be difficult to land on as its gravity well is high and unlike Laythe, there isn't an atmosphere that you can slow down or use parachutes in. But this does come with the advantage of being able to use many space-only engines like the Cheetah or Poodle. So it's a fair trade off by me.

Bop

Bop as seen from orbit.
Physical Properties
Radius: 65 km
ASL Gravity: 0.06 g
Escape Velocity: 276.6 m/s
Has Atmosphere: No

Bop is a small asteroid in an elliptical and inclined orbit of Jool. In Kerbal mythology Bop is said to be the home of the Deep Space Kraken, which was a bug that destroyed ships in KSP versions of yore. This myth is actually true - there is a dead Kraken located somewhere on the surface of Bop.
Urban legends aside, Bop is notable for having a somewhat high timewarp altitude limit: the minimum warp-able orbit altitude exceeds that of the near space science altitude. This can make low orbits of Bop very annoying as you can't warp through it.

Pol

Pol as seen from orbit.
Physical Properties
Radius: 44 km
ASL Gravity: 0.038 g
Escape Velocity: 181 m/s
Has Atmosphere: No

Pol is the smallest and outermost of Jool's moons. It is a small and lumpy asteroid named for its resemblance to a pollen grain. Its surface is quite rough, so landing can be difficult at times because of the mountains and low gravity combined.

Sarnus System

Sarnus

Sarnus as seen from orbit.
Physical Properties
Radius: 5300 km
ASL Gravity: 0.298 g
Escape Velocity: 5565.7 m/s
Has Atmosphere: Yes
Atmospheric Properties
Height: 580 km
ASL Pressure: 14 atm
ASL Temperature: 167 k
Contains Oxygen: No

Sarnus is a beautiful gas giant with a large and prominent ring system. It is the first of the planets included in the Outer Planets Mod, and is the KSP analog for Saturn. Because of Sarnus' distance from Kerbol, solar panels only have 1% effectiveness. Therefore, bringing along alternate power sources (such as RTGs) is recommended. Its gravity is quite low for its size, and it likely has the lowest density of all the planets in the system.

Its rings are right to its equator, so if you want to get stunning views from orbit, you'll need to incline your orbit somewhat. Its true color is salmon, but in reality it actually appears a more pinkish color. It too has five moons: Hale, Ovok, Eeloo, Slate and Tekto.

Hale

Hale as seen from orbit, with Sarnus in the background.
Physical Properties
Radius: 6 km
ASL Gravity: 0.0023 g
Escape Velocity: 16.5 m/s
Has Atmosphere: No

Hale is a tiny moonlet orbiting within Sarnus' ring system. Because it is so small, a proper lander can be impractical; you can often get away with a tiny, ion-powered probe or even just a Kerbal on EVA and still make it home. You'd better bring your camera, as some of the most impressive views in the entire solar system can be taken here.

Ovok

Ovok as seen from orbit, with Sarnus in the background.
Physical Properties
Radius: 26 km
ASL Gravity: 0.002 g
Escape Velocity: 31.9 m/s
Has Atmosphere: No

Ovok is another tiny moon orbiting Sarnus, and it's on the edge of the ring system. Its gravity is even lower than that of Hale, indicating it likely is made of nearly all ice. It is stretched into an egg shape by the tidal forces of the other moons and Sarnus itself.

Eeloo

Eeloo as seen from orbit.
Physical Properties
Radius: 210 km
ASL Gravity: 0.17 g
Escape Velocity: 841.8 m/s
Has Atmosphere: No

Eeloo is a modestly sized moon, and the innermost of the major moons of Sarnus. Its surface is grayish and dotted with numerous small craters. It might be home to a sub-surface ocean located beneath the ice, evident by the brownish grooves all over its surface.

Slate

Slate as seen from orbit, with Sarnus in the background.
Physical Properties
Radius: 540 km
ASL Gravity: 0.69 g
Escape Velocity: 2707.2 m/s
Has Atmosphere: No

Biggest of the moons orbiting the ringed giant, Slate is a dry and rocky world covered in mountain ranges. It is similar to Tylo in that it is large but lacks atmosphere. According to its description, Slate may have once had an atmosphere but it has been stripped away by an unknown cataclysm. Its big SoI and high gravity can be used to gravity assist a craft into a lower Sarnus orbit, or send them flying out of the system entirely.

Tekto

Tekto as seen from orbit, with Sarnus in the background.
Physical Properties
Radius: 280 km
ASL Gravity: 0.25 g
Escape Velocity: 1172.4 m/s
Has Atmosphere: Yes
Atmospheric Properties
Height: 95 km
ASL Pressure: 1.23 atm
ASL Temperature: 94 k
Contains Oxygen: No

A somewhat large moon with a thick atmosphere, Tekto is similar to Laythe, but it trades larger size for having a thicker atmosphere. Its atmosphere is slightly thicker than Kerbin's, and is shrouded in thick clouds like Eve. It has oceans of liquid methane on its surface, and with this, it is a perfect Titan analog. Tekto is an aviator's paradise: while unlike Laythe it lacks oxygen, you can fly much more efficiently due to thicker air.

Tekto might have the ingredients for the building blocks of life on its surface. We don't know exactly for sure.

Urlum System

Urlum

Urlum as seen from orbit.
Physical Properties
Radius: 2177 km
ASL Gravity: 0.257 g
Escape Velocity: 3312.6 m/s
Has Atmosphere: Yes
Atmosphere Properties
Height: 325 km
ASL Pressure: 7 atm
ASL Temperature: 95 k
Contains Oxygen: No

Distant and mysterious, Urlum is the first of the ice giants. Still though, you can't land on it, as with Jool and Sarnus. It is the second planet added in the OPM, and is KSP's counterpart to Uranus. Unlike the other planets it is supposed to rotate retrograde to its orbital motion. (However, ingame it does not seem to do this.) Urlum has a thin ring system nowhere near as impressive as that of Sarnus.

Its odd system of four moons consists of Trojan satellites Polta and Priax, as well as the larger Wal and its moon Tal.

Polta

Polta as seen from orbit.
Physical Properties
Radius: 220 km
ASL Gravity: 0.19 g
Escape Velocity: 905.4 m/s
Has Atmosphere: No

Polta is a medium sized moon with a surface that is mixed with colors of gray and teal, that makes it look a little like a larger Minmus. It shares its orbit with the much smaller Priax, which orbits 60 degrees behind it at all times.

Priax

Priax as seen from orbit, with Urlum in the background.
Physical Properties
Radius: 74 km
ASL Gravity: 0.063 g
Escape Velocity: 302.4 m/s
Has Atmosphere: No

Priax is the orbital companion of the larger moon Polta. It is a grayish colored rock with a very cratered surface. From Priax you can get an impressive view of Urlum's ring system, as it orbits just on the edge of it.

Wal

Wal as seen from orbit, with its tiny moon Tal in the background.
Physical Properties
Radius: 370 km
ASL Gravity: 0.37 g
Escape Velocity: 1638.6 m/s
Has Atmosphere: No

Wal is the largest moon of Urlum, and is known for it looking similar to a walnut. Wal appears to be a transition from the smaller moons like the Mun or Polta and the bigger moons like Laythe, Tylo or Slate. Its surface is colored many different shades of brown and tan, and is dotted with craters. One notable feature is the large ridge that straddles its equator. However, all of these are nothing compared to Wal's biggest claim to fame: it has a moon, despite being a moon itself!

Tal

Tal as seen from orbit.
Physical Properties
Radius: 22 km
ASL Gravity: 0.045 g
Escape Velocity: 139.3 m/s
Has Atmosphere: No

Tal is extremely special, as it is the only submoon of the entire Kerbol System. In short terms, a submoon is a moon of a moon. In other facts, its surface is quite smooth and devoid of craters compared to other asteroid moons. It is also brown, just like its parent.

Neidon System

Neidon

Neidon as seen from orbit.
Physical Properties
Radius: 2145 km
ASL Gravity: 0.314 g
Escape Velocity: 3634.6 m/s
Has Atmosphere: Yes
Atmospheric Properties
Height: 260 km
ASL Pressure: 6 atm
ASL Temperature: 90 k
Contains Oxygen: No

Neidon is the outermost of the gas giants added by the OPM. It is the counterpart to Neptune. Because of its distance, Neidon can be difficult to get to without gravity assists or repeated engine burns. Its system is quite barren compared to the other outer planets: it has only two moons, Thatmo and Nissee. Both of them follow elliptical and highly inclined orbits.

It's not uncommon to find lots of Unknown Objects around Neidon, and as such, you can track them and set up a mining base circling it or one of its moons.

Thatmo

Thatmo as seen from orbit.
Physical Properties
Radius: 286 km
ASL Gravity: 0.232 g
Escape Velocity: 1140.8 m/s
Has Atmosphere: Yes
Atmospheric Properties
Height: 35 km
ASL Pressure: 0.01 atm
ASL Temperature: 73 k
Contains Oxygen: No

Thatmo is a large and cold moon with an extremely thin atmosphere. It is the KSP counterpart to Neptune's moon Triton. The atmosphere, which is only 1% the pressure of Kerbin's is barely useful for aerobraking, and using any kind of parachutes is impossible. Aerodynamic flight is possible but difficult. Last but not least, Thatmo orbits retrograde, so any encounters will likely be rendezvous instead of Hohmann transfer.

Nissee

Nissee as seen from orbit.
Physical Properties
Radius: 30 km
ASL Gravity: 0.045 g
Escape Velocity: 162.7 m/s
Has Atmosphere: No

Nissee is the outermost of Neidon's moons, and it is a tan colored asteroid with craters. Its orbit is highly elliptical and inclined, so it is difficult to encounter. Landing on Nissee however, is fairly straightforward. It is the analog for Neptune's moon Nereid.

Plock System

Plock

Plock as seen from orbit.
Physical Properties
Radius: 189 km
ASL Gravity: 0.148 g
Escape Velocity: 740.7 m/s
Has Atmosphere: No

A dwarf planet far beyond Neidon, Plock is the outermost body added by the OPM, and is the analog for Pluto. One thing is certain about Plock: it's a very long way from home, and is difficult to get to as a result. It's not alone though, it and its moon Karen keep each other company as they wander through the cosmos.

Karen

Karen as seen from orbit, with Plock in the background.
Physical Properties
Radius: 85 km
ASL Gravity: 0.066 g
Escape Velocity: 331.8 m/s
Has Atmosphere: No

Karen and Plock form a very unique double dwarf planet system. Beyond it lies simply empty space. Yeah, there's not much else to say about it, really.

[dkr127054]

mod name pls

[Soilaf]

@eclips_e#0001

Sorry for being super late responding. Yes, I do plan on making another guide someday. I don't know too much about Interstellar Extended but I might make one based of GPP or JNSQ later. Maybe even Whirligig World just for the fun of it

[Rhynocx]

@riptionaryX

too cold for life as we know it. stop being small minded. life can come in many forms we don't know or understand yet and its even more silly to use real "life logic" in a game. hell, kerbals arent even human and could be selenium based for all we know.

[RiptionaryX]

Yo, i noticed something wrong with this guide, you wrote: "However, Jool's mass is not enough to sustain that on its own: the rest must be from the atmospheric greenhouse effect. With the presence of oxygen it is very possible that Laythe has life."

Laythe IS too cold for life, all the liquid water ocean on the surface is due to the tiny ammount of warmth it gets due to as you said tidal heating and the greenhouse gasses, and the the metric f#ckload of salt in the water. which also ruins any possibility of life, yes it has a thick oxygen rich atmosphere, but no its not possible for life to exist.

[7Zip File Manager]

good job on this guide! perhaps you can make an Interstellar Extended one next?

[Soilaf]

Mods used: Stock Visual Enhancements, Distant Object Enhancement, EVE
OPM = Outer Planets Mod