A better "closest approach" finder

[king of nowhere]

recently i have gone to bop, then from bop to pol, and now i am trying to go to eeloo, and each of those tasks would not be hard, if there was a decent way for predicting orbits.

For you see, I know that eeloo will be in the orbital node around year 13, day 1. And I know that my ship is not too far from that. But I cannot visualize it in any way. I'm shooting blind. Sometimes I find a close approach. it says something like 5 million km. then i fiddle a bit with the manuever. and i gradually reduce that until... it disappears. and get replaced by another close approach that's bound to happen in 25 years, at tens of millions of km. I keep getting "close approach" markers at the farthest points from the nodes, where I cannot possibly get an approach. And I'm growing quite angry at it. this has nothing to do with skill, it's a limitation in the game's ability to give informations.

So I conceived an easy solution: the ability to set up where you want your close approach. So I would be able to point on eeloo at the orbital node and say "I want to have an approach here", and then the game will always show me the closest approach there, it will show me how close I am to hitting eeloo on the node. It would show where my ship would be when eeloo is in the chosen position. perhaps a nice time interval, "give me the closest approach in a time window between 3 years 300 days and 4 years 100 days from now".

that can't be too hard to implement.

[IanCanberra]

When you use Mech Jeb there is the editor. If you open that up you can change values. Even very minor decimal point values. Then Update it.

I suggest you try it first on a mun or minmus orbit and see how it works

[natsirt721]

The problem is that the the closest approach indicator looks for a local minimum distance, rather than the absolute minimum distance along the entire orbit of the vehicle you're planning for (or something like that, either way it doesn't do a good job). For simple orbital geometry this is sufficient, but you appear to have found one of the cases where it is not (planning a direct transfer from kerbin to Moho is another one). Fortunately, there is a workaround, not altogether unlike the solution you have described.

When placing maneuver nodes, the closest approach algorithm starts searching from the time of the final node in the plan. If you know approximately when your intercept will be, you can place an empty node at that time, and the closest approach indicator will snap to the time of the node, or the next minimum distance after it (usually the former, in my experience). From here, you can do a two-step dance; tweaking the burn vector slightly and adjusting the time of the dummy node until you achieve an SOI change.

[Superfluous J]

If it's so hard to program a predictor (they've tried before. Believe it or not it used to be worse) then I'd be happy with the interface showing me a ghost of where my target soul will be when my ship is at the location of its orbit where my cursor is.

Like how now it shows it during SOI encounters, only directly under my control.

[Corona688]

You need to double-click on the planet to select it as a target.  Then it will show closest-approach as tick marks, just like a spacecraft encounter, whenever it doesn't end up close enough for SOI change.  You can right click on the tick marks for detailed information.

Encounters in the very far future may not be that precise.  That's OK, neither are your engines.

Edited October 15, 2020 by Corona688