Orbit Calculations From Duna SOI Broken

[afyber]

When in Duna' SOI and attempting to create a maneuver node for an interplanetary transfer back to Kerbin something goes wrong in the orbit calculations. Because if I make a maneuver node that should make the orbit bigger (burning along Duna's prograde), the orbit line appears to be a smaller orbit (around the sun). This stops happening once you leave Duna's SOI, so you can create a maneuver which appears to give an encounter with Kerbin, but only from Duna's broken calculations, so once you leave the SOI the orbit has gotten bigger instead of smaller. This also works the other way, if you make a maneuver to burn Duna's retrograde, which should make the orbit smaller, it appears bigger until you leave Duna's SOI.

[LameLefty]

This bug has been noted by numerous others. See for example:

In fact, this bug has been with us since day 1:

Hopefully it gets corrected in Patch 2. 

[The Aziz]

So it's still not fixed. Bummer.

Well honestly the current workaround is to not trust the shown trajectory, but rather focus and setting up the maneuver node in the right place, in front of the planet for lowering orbit, behind for raising. Any errors you can fix after leaving SOI.

[LameLefty]

1 hour ago, The Aziz said:

So it's still not fixed. Bummer.

Well honestly the current workaround is to not trust the shown trajectory, but rather focus and setting up the maneuver node in the right place, in front of the planet for lowering orbit, behind for raising. Any errors you can fix after leaving SOI.

Yep.  Basically, just use one of the online phase-angle calculators to get yourself into the correct position for the transfer burn, then burn just enough to exit the current SOI. Once outside the current SOI, make the rest of the burn necessary for an intercept. 

[The Aziz]

While not the most efficient - losing a lot from  oberth effect - it does the job.

[D-Rex]

Can confirm. Just saw this behavior while trying to leave Minimus on way back to Kerbin. Following the maneuver actually resulted in elevating my orbit and leaving the kerbin SOI.

 

[Rocktagon619]

Maybe it has something to do with mission time versus actual time. Since what time it is in the simulation is very important to this game, could it be confused and think it's in a different time frame? This could be a consequence of multiplayer maybe needing to have different frames of reference for what time it is and where planet SOIs would be at that given time. 

When this happened to my duna-ike mission, re-docking my lander after the duna ascent caused the mission timer to reset and give me some kind of "vessel launched" pop-up. Re-setting the timer would make the game think it's on the wrong side of the kerbolar system when I tried to burn back to Kerbin.