800ish delta V game engine error?

[NeverEnoughFuel!!]

Well, last night I was constructing and launching my first manned mission to Moho... according to TWP total delta V (including orbit insertion) was about 4700ish, after ejection of 1300 delta V, and inclination/braking correction of about 900-ish, I had a perfect encounter, and a equatorial flyby of about 50 km altitude counterclockwise, with expected capture maneuver of about 1800ish delta V to circular orbit... great! My encounter was not of the flickering one type... solid as a rock! After some fiddling with my science labs in Minmus orbit, I returned to my Moho ship and after some time warp suddenly, out of nowhere, I realize that I will miss Moho while I'm in visual range! My encounter was gone and I had to burn retrograde about 800ish to regain my encounter again at the same place and the same conditions as before? What the hell happened?!! Game engine error of 800 delta V?

Yes, I did land, pick up science, back in orbit, put my pilot in cryonic chamber, and now waiting for transfer window back... even more weird stuff is happening... according to KAC I have to wait about 75 to 85 days for window to open, but when I plug that time frame in TWP I get tremendous delta V requirements... and guess what... I don't have enough fuel! BUT, if I use TWP only, without KAC I get waiting time of 200 days and barely  enough delta V to get back, by barely I mean about 10-15 m/s left in my argon tanks... So it's 200 days waiting vs 85 days waiting... how? How is such a big difference possible? Moho elliptic orbit? I know where lies my biggest mistake... landing with TWR of 1.12-1.33 with my Near Future Vasimir and ion engines... that took a lot of fuel because I had to drop it from 31 km altitude with constant braking... but I knew it will be problematic landing, after all it's not my first time to land with such a low TWR somewhere... but I want my 800 delta V back! If that didn't happened I could easily get back! This will probably lead to sending some probe with some additional argon for refueling... but these math mistakes are deadly.

 

[Streetwind]

It's hard to say what happened, since we couldn't see it happen. Sometimes an intercept will just stop being displayed - but as long as you're on the same trajectory, you will still encounter your target all the same. Maybe this happened to you. Maybe not. Can't say for sure.

[bewing]

This behavior as been reported once before, but the devs can't duplicate it in stock KSP. And since you are using mods, it's impossible to say where the bug is happening.

 

[Rosco P. Coltrane]

Is your orbit changing by any chance? I have this happened several times now, my ship would start experiencing phantom forces that change it's trajectory and good by encounter... or anything else really because at that point you're doomed as your orbit will keep changing no matter what you do.

Edited December 18, 2016 by Rosco P. Coltrane

[NeverEnoughFuel!!]

@Streetwind

No, that's not the case... I've seen it before... sometimes it happens when I'm traveling to Minmus... this was almost as I never did do inclination/braking correction maneuver... 

@bewing

I think it has something to do with orbit trajectories... more precisely with conics... I've noticed that when I'm trying to get an encounter i.e. dragging-pushing prograde retrograde, at the moment where I should get an encounter - conics disappear - only to appear a moment later when my "miss" distance increase - similar to the problem with disappearing/flickering rendezvous conics... I think I saw such thread here... btw I'm still in 1.1.3

@Rosco P. Coltrane 

No there was no phantom forces... only thing I did was to rotate ship to retrograde position in preparations for braking...

Ok, guys thank you for your time... but what about this mess with KAC and TWP? Any suggestions, thoughts?

Edited December 18, 2016 by NeverEnoughFuel!!

[DD_bwest]

did you go to full warp from regular time at all?    while significantly less common on 1.2, there is still the rare case that you go to warp and you wont get your same trajectory.  ive had incidences where ill finish a burn to give myself a precise insertion, and going to warp after will make it as if i never did the burn.  the more times you go to warp, the more times you risk it doing this. I find that Clicking on a high up arrow, or selecting a place to warp to(excluding warp to manuever)To be the 2 most likely things that will cause it to change on a warp.

creating a maneuver and warping to it tends to be pretty good, although ive still seen small changes doing that.what i generally do is to save before all warps, and to go to 5x warp before i ramp it up high, or click on a place to warp to.  i find going to the low warp first tends to lock everything in place

[NeverEnoughFuel!!]

2 hours ago, DD_bwest said:

did you go to full warp from regular time at all?    while significantly less common on 1.2, there is still the rare case that you go to warp and you wont get your same trajectory.  ive had incidences where ill finish a burn to give myself a precise insertion, and going to warp after will make it as if i never did the burn.  the more times you go to warp, the more times you risk it doing this. I find that Clicking on a high up arrow, or selecting a place to warp to(excluding warp to manuever)To be the 2 most likely things that will cause it to change on a warp.

creating a maneuver and warping to it tends to be pretty good, although ive still seen small changes doing that.what i generally do is to save before all warps, and to go to 5x warp before i ramp it up high, or click on a place to warp to.  i find going to the low warp first tends to lock everything in place

WHAT?! Yes I did warp... with different speeds, so warping can destroy encounter? Ohhhhhh man ... so what we are suppose to do? Play real time? Will this affect crafts while they are not in focus? A player has some other things to do for the time it takes for a craft to get somewhere... contracts, science... this is really really bad developing... until now something like this shouldn't happen ever! Flickering conics in orbit during rendezvous I can manage, because I've done it so many times... but this is really under the belt punch! I'm sooo maaad 

Thanks for the info man, my anger is not directed at you... I'm definitely going back to warp drive... this is BS... three different tools for transfer planing, each one gives different data, you can't plan and predict anything without tonnes of redundancy fuel... and now I can't even warp without risking to destroy my mission? Forget it...   

[DD_bwest]

1 minute ago, NeverEnoughFuel!! said:

WHAT?! Yes I did warp... with different speeds, so warping can destroy encounter? Ohhhhhh man ... so what we are suppose to do? Play real time? Will this affect crafts while they are not in focus? A player has some other things to do for the time it takes for a craft to get somewhere... contracts, science... this is really really bad developing... until now something like this shouldn't happen ever! Flickering conics in orbit during rendezvous I can manage, because I've done it so many times... but this is really under the belt punch! I'm sooo maaad 

Thanks for the info man, my anger is not directed at you... I'm definitely going back to warp drive... this is BS... three different tools for transfer planing, each one gives different data, you can't plan and predict anything without tonnes of redundancy fuel... and now I can't even warp without risking to destroy my mission? Forget it...   

its got a lot better over time, ALOT better.   the easiest way to notice is it set up an encounter with planet and focus on it, then from no warp click on max warp and it should bounce a bit, sometimes its small, sometimes its not.  Im sure there is a technical way to figure it out, and i believe there is some long complicated reason for why it does it and used to do it alot more. being at a high right of warp between SOI changes used to also cause problems but thats got better to.

your alot safer in the tracking station, as i cant think of a time seeing it happen in there, but it can be a pain to go there just to warp.  Going to first warp speed before you do a big warp helps alot, it tends to lock in where your going. i always do it with no exceptions.  easing into it is what you want, its the hoping between nothing straight to a high rate that tends to cause problems, for me anyways. 

[FullMetalMachinist]

3 hours ago, NeverEnoughFuel!! said:

Ok, guys thank you for your time... but what about this mess with KAC and TWP? Any suggestions, thoughts?

The short answer is that because of Moho's eccentric and inclined orbit, the dV costs of transfer windows can vary widely from one to another. The solution is to basically ignore traditional transfer windows. See this post (it's old, but still relevant).