First of all, it is a sub-branch of physics that studies the forces acting on dynamic objects and the movements of objects in the direction of these forces. These issues can be studied in more detail. I'm just going to examine the laws of physics and examples, for understand to the game universe's modeling.
I will examine the dynamics of the game in 3 parts. Dynamics of planet and asteroid, dynamics of bodies and also dynamics of rocket.




I will name the Solar System in the Game as the Kerbol System since the name of the Star is Kerbol. There is 1 star and 6 planets in the Kerbol System. So that this guide does not turn into a physics lesson i will not solve complex sets of equations but i will compare it with our own Solar System for easy understanding.

There is a ratio of 1.08 between the gravitational acceleration of Kerbin, our home planet in the game, and the gravitational acceleration of the Earth. From this point of view, we can use the laws of physics we know to understand Kerbin dynamics.



If we substitute the information we know about the Kerbin in the above equation, the gravitational acceleration we have calculated for the Kerbin will be 9.807 m/s. There is a difference of 1.0003 between the given and the calculated result. According to this calculation, we can talk about a 0.03% margin of error. Such a small number is negligible for this game.

We can interpret this result as the physical movements that will take place on the planet are modeled in accordance with the real laws of physics. Let's examine Kerbin's movement in space too. For this, we will use the following equation.



Again, taking the information we have with the Earth as a reference, we can interpret that the given orbital speed of Kerbin has a 0.01% margin of error according to the real laws of physics, and again, due to the smallness of this number, we can that interpret the movements of the game's planets in space are modeled in accordance with the real laws of physics.



We can look at body dynamics in much more detail for different situations in planets and space. We will test the general situations and their compliance with real physics laws. We will do this using the Free Body Diagram below.



In order to test this, I chose the planet Kerbin to use the results we calculated in the previous topic and created the following experimental setup. In this experimental setup, I released a mass of 1346 kg without speed from a height of 972 m and it reached the ground in 14 seconds. If we combine this experiment with the above equation to understand its experimental setup, we get such a result.



If we use the following mechanic equations to test the real laws of physics we have gained in this experiment.



We can prove the accuracy of the calculations with the mechanical formulas, with the result of the experiment and the information in the experiment. That's why we can say that the object dynamics too in the game are also modeled according to real physics laws.

The last property I want to test is air density. In this way, we will have analyzed all the necessary information about a planet. In order to test this, I chose the planet Kerbin to use the results we calculated in the previous topic and created the following experimental setup. In this experimental setup, i fully opened the mk16 parachute at 514 m and its weight of 1146 kg reached the ground with an average speed of 6.2 m/s in 118 s. If we combine this experiment with the above equation to understand its experimental setup, we get such a result.


In this experiment, I used the Rocket Fx program for the accuracy of the results. I entered the information in the experiment into the program and compared this experiment with the information given. According to real physics formulas, I calculated 0.58% margin of error in the experiment.


You can find more detailed information about this on Rocket Fx. Against this result, I calculated an air density of 1.21-1.22 kg/m^3 at sea level for Kerbin. According to the information given The atmosphere of Kerbin is patterned after Earth's U.S. Standard Atmosphere (USSA), though with the vertical height scale reduced by 20%. You can find more detailed information about kerbin's atmospheric density on the game's wiki website.

This topic is the subject of the lecture in the academy. I will therefore break down the spacecraft physics into parts and analyze some important points for the Kerbal Space Program game's dynamics.


In fact, spacecraft are simple structures. Their only purpose is to be a vehicle that can travel in space. We can cite Apollo 11 or Tesla Roadster as an example. The spacecraft in both examples were launched to go to a certain place in space with the same laws of physics. One aimed at a point, while the other aimed at a trajectory. I will analyze the orbit part as orbital mechanics in a separate topic. Now let's see if we can use the real laws of physics to send a spacecraft to another space rock in KSP, like Apollo 11 targeting the Moon. This time I will do theoretical work before experiment for analysis.

If you throw anything at a certain angle in the atmosphere, we can calculate how much power is required for a certain range with the following formulas.


After this calculation, we can use the following formulas for the required force.


To examine these formulas for a spacecraft traveling through space, we must switch from dynamic to astrodynamic. For this we need 2 more calculations. These are stability and Delta V. I will use the thrust to weight ratio page at Rocket Fx application to calculate the stability.

I will analyze the Delta V account from the delta V map published on Kerbal Space Program Wiki.



According to the map, we need 3400 m/s delta V to sit in low Kerbin orbit at 80 km. To make our analysis clearer, I will try this with a simple rocket and try to sit in low Kerbin orbit at an average of 75 km at 3400 m/s delta V. I also consider the margin of flexibility in such calculations.
First of all, I am calculating again. If we try to calculate the 3400 m/s delta V value required to ascend from the Kerbin surface to the low Kerbin orbit with real physics formulas, we need to use the following formula.


Thus, for the total DV, it is necessary to calculate again with the above results in the formula below.


Since the theory is ready, I can build a rocket with the information in the Kerbal Space Program and analyze whether the result is in accordance with the theory, that is, whether the spacecraft in the Kerbal Space Program act according to real physics.

I will use a capsule for the rocket, a hood on the capsule to reduce aerodynamic effects, fuel tanks and an engine. You can reach the rocket I used from my Steam Workshop with the link below.

Low Kerbin Orbit Rocket [No Modes]



The rocket I designed has a DV of 2833.9 m/s according to the above calculation and Kerbal Space Program calculated this DV as 2831 m/s. According to the DV map, I calculated 3554 m/s DV in vacuum for 3400 m/s in vacuum and landed in a circular orbit at about 73.5 km and still has 77 m/s DV on the rocket. I actually used 3477 m/s DV for this orbit. This makes the DV calculation for Kerbal Space Program with 0.1% margin of error. The trajectory and DV difference according to the DV map may differ according to the rocket's ascent profile. Still, reaching 8.8% faulty orbit with a 2% margin of error can be ruled out for Kerbal Space Program with a good pilot and better elevation profile.



One of the biggest factors affecting the rocket's elevation is the stability of the rocket. He can have an idea about the stability by calculating the thrust-weight ratio. So I will use the Rocket Fx app to calculate the stability.


Rocket Fx calculated the stability for this rocket as 1.67 with the values in Kerbal Space Program. Kerbal Space Program also calculated this value as 1.67. This is exactly the same result.

Kerbal Space Program has 8 sensors that analyze the physics of the universe. Environment analysis with 5 of them, material analysis with 2 of them and atmospheric analysis is performed with one of them. With PresMat Barometer, one of these sensors, the atmospheric pressure is 100.13 kPa at 100 meters. Being measured. According to Kerbin Space Program Wiki information, this value is 101.324 kPa for 100 meters, this difference is in accordance with the real laws of physics. Thus, the open air pressure is calculated as 1.225 kg/m^3. I used this value in the fall calculations and it was correct.
Proven theoretically and experimentally.

When we measure the temperature of space with the 2HOT Thermometer, the value of 172.7 K comes out. Whereas space is 2.7 K. There may be a decimal error in the measurement or notation here. This value was the only real non-physical value that I observed.

To conclude for us the kinematics and dynamics for the planet and asteroid in the game, Kerbal Space Program is a game modeled according to real physics laws. Although the results do not have to be the same as on Earth, the same experimental results can be achieved with the same formulas. In this way, the space experiments that are actually wanted to be done can be simulated by Kerbal Space Program and Kerbal Space Program maybe create added value for difficult experiments.


I can say that this analysis was very successful in summary. Both for the Kerbal Space Program and for the charity-made DV map posted on the Kerbal Space Program Wiki.
The margin of error value in the DV account is great for a game because you can neglect this value to reach your destination on your flight. The trajectory and calculations I reached with the rocket I built according to the DV map, since these calculations are not precise in the real world, there is a certain range, and what I calculated for this analysis is average value for these intervals. In the calculation of the thrust-to-weight ratio, the value of 1.67 is the medium for a rocket to rise steadily. They usually keep this value between 1.5 and 2.0 for rockets taking off from Earth. These intermediate values also say that the rocket will not deviate from the direction of rise enough to change the target.

I want to thank you for your interest in this guide. Since it was favorited by 100 people, I made a case study with the information I analyzed in this guide and I would like to share it with you. In the example I did the calculations of a station to model Kerbin's gravity for the kerbonauts. You can find the sample here if you're interested.

Scientific Solution for Kerbonauts Who Want to Stand in the Space Station in English