How do you caculate a transfer window?

[Dr. Kerbal]

SO I am making a planet mod and I want to provided my players with some information HOW TO GET THERE INCLUDING A TRASNFER WINDOW. Does anyone know how you can calculate it? 

[Dientus]

Understand I just got this information looking it up, I have not had time to actually crunch any numbers but I am hoping that these sites will bring you the formula you need to arrive at the answer.

 

https://www.jpl.nasa.gov/edu/teach/activity/lets-go-to-mars-calculating-launch-windows/

 

https://www.reddit.com/r/KerbalAcademy/comments/1wvtsl/manually_calculating_launch_windows/

 

[magnemoe]

You have the porkshop diagrams, think this is an mod module for KSP as Mechjeb uses it and it works for transfer to objects in solar orbit in KSP not only the planets and it also works between Mun and Minmus and between jool's moons. 

[GoSlash27]

The way I do it is this:

1) calculate the vis-viva of the transfer

2) find the SMA of the transfer and thus the period, and divide by 2.

3) calculate the mean angular velocity of the source and destination bodies, then redefine the angular momentum of the destination relative to the source.

4) divide the relative angular velocity of the destination by the transfer time.

5) subtract the angular displacement from 180°.

My calculator is very simplified and assumes coplanar and circular orbits. It also assumes I'm making an ideally efficient transfer burn.

HTHs,

-Slashy

P.S. @OhioBob has an excellent resource for the math involved in orbital mechanics. It's my go-to source.

http://www.braeunig.us/space/orbmech.htm

 

Edited August 4, 2021 by GoSlash27