Time between transfer windows?

[NeverEnoughFuel!!]

Well, as the title says, what is the average cumulative waiting period for transfer window per planet? I can get date and travel time to a planet from TWP, but I don't know how long I need to wait there for next transfer window, this is directly connected to amount of life support supplies, this can be mended with cryogenic chambers in the case of one man ships "get the science and run" missions, but I would like to send a bigger ship with mobile lab and ISRU capabilities to an orbit of let's say Duna and produce science/fuel there while waiting for next transfer window... so it means at least four crew members two scientist, two engineers, but I don't know how much supplies to bring with me...    

[bewing]

Are you intending to transfer back to Kerbin, or out to some further CB?

[NeverEnoughFuel!!]

Back to Kerbin... basically I need some spreadsheet who says for example, Duna-Kerbin waiting time X years, Dres-Kerbin waiting time X years, etc. etc...

[diomedea]

If planetary orbits had no eccentricity, the correct phase angle for a transfer window would present with chronometric precision after one full synodic period from the last. So, for each kind of transfer (e.g., Kerbin -> Duna) we could write down a succession of dates when the transfer is optimal. Doing so with the back transfer too, then comparing arrival date with the first next date for return, would give what you need.

However orbits are eccentric, so transfer windows aren't so regular. Therefore I still prefer to check transfer windows both ways when planning each interplanetary mission (same with tours, I check each transfer).

[Waxing_Kibbous]

TWP gives you the tools to do this, you can adjust the date ranges and planets in its UI. I recommend adding KAC to help in planning alongside TWP.

[GoSlash27]

NeverEnoughFuel,

My formula for window frequency is this: ABS[perAperB/(perA-perB)]; the product of the periods divided by their difference.

Kerbin -> Duna occurs once every ABS[1*1.88/(1-1.88)] =  2.14 years.

HTHs,
-Slashy

Edited January 22, 2017 by GoSlash27

[NeverEnoughFuel!!]

@GoSlash27  Thank you, but  how did you get the periods, where is that data?

@Waxing_Kibbous Ohhhh stupid me... you are suggesting to simulate waiting in TWP, i.e. calculate date for transfer from destination, after arrival date at destination, and add those numbers of days? How I didn't remember that?

Edited January 22, 2017 by NeverEnoughFuel!!

[GoSlash27]

NeverEnoughFuel,

 My spreadsheet calculates each sidereal period from the sun's mass, the universal gravitational constant, and each planet's semimajor axis. That information is all available in the tracking station (or at least enough info to calculate it). You can, however, plug in those numbers from the wiki.

Best,
-Slashy

 

Edited January 22, 2017 by GoSlash27