SOLVED: Minmus transfer angle does differ from KSP 1, why?

[Jeq]

At ksp 1 minmus transfer angle is 45 degrees, as almost any other moon and planet in game. Why it is almost 90 degrees at KSP 2?

Mathemtaically was it wrong in ksp 1 or is it wrong in ksp 2?

 

I noticed this when i were making comparison of ksp 1 and ksp 2 flight to minmus. https://youtu.be/P23Z5W8xYfQ?si=kMqlk8zWeBBnDIS6

KSP 1 maneuver is at 9:47 and KSP 2 maneuver 12:00 in video

FIX: i am not talking real transfer angle, i am meaning angle between apoapsis of maneuver, kerbin and minmus.

FIX FIX: It seems it doesn't differ

Edited December 13, 2023 by Jeq
There was no problem

[Gargamel]

IIRC (and I know somebody will point it out if I'm wrong ) I believe they tweaked minmus's orbit a bit... for reasons.

 

[Superfluous J]

How did you determine this, with math (that I won't understand) or testing (which is how I do it)?

Minmus is far out in Kerbin's SOI and at Ap your transferring vessel can spend a LOT of time out there nearly hovering. It is quite possible that you are giving your ship a TAD too much thrust so it is encountering Minmus much later than an optimal (with a lower Ap that still intersects Minmus' SOI) transfer would.

Note: I've not tested this myself, but I never did in KSP1 either because I transfer to Minmus' An or Dn, and ignore where Minmus actually is in its orbit. I utilize the "problem" above to know I can transfer at any time regardless of where Minmus actually is in its orbit.

[18Watt]

Not sure what you mean by 'transfer angle'.  But I always used about 100 degrees lag to transfer to Minmus in KSP1.  In other words, Minmus is leading the ship by about 100 degrees when I start my burn.  

In KSP1, you could start your burn with a 45 degree lag, but that would waste a lot of fuel.

[Jeq]

I tested in this video. Both videos i set apogee to 46,400km and moved maneuver node until it matched arrival at apogee with minmus. At navball you can see how different positions minmus is at KSP 1 than KSP 2 at start of burn. This is worrying me a lot.

14 hours ago, 18Watt said:

Not sure what you mean by 'transfer angle'.  But I always used about 100 degrees lag to transfer to Minmus in KSP1.  In other words, Minmus is leading the ship by about 100 degrees when I start my burn.  

In KSP1, you could start your burn with a 45 degree lag, but that would waste a lot of fuel.

I am not talking real trasnfer angle, i am just using angle of target from prograde when making burn.

Edited December 12, 2023 by Jeq

[The Aziz]

5 minutes ago, Jeq said:

This is worrying me a lot.

Why? Your saves are incompatible anyway.

Edited December 12, 2023 by The Aziz

[Jeq]

8 minutes ago, The Aziz said:

Why? Your saves are incompatible anyway.

Because KSP must be mathematically correct. If its incorrect then developers will have huge problems making anything work. If minmus moves at incorrect speed at its current orbit then its incorrect and cannot be calculated.

Edited December 12, 2023 by Jeq

[Guest]

13 minutes ago, Jeq said:

Because KSP must be mathematically correct.

How do you figure it’s not correct if they’ve changed the orbit?

[Jeq]

Just now, Periple said:

How do you figure it’s not correct if they’ve changed the orbit?

Orbit is same than in KSP 1, 46,400km, when i played and calculated orbits at KSP 1, speed of minmus and orbit speeds matches at that altitude for real calculations.

[MechBFP]

I think there is a bug report about that, but the search on this forum is completely useless garbage, so good luck trying to find it. 

[MechBFP]

In any case Minmus should complete 1 full orbit in 49 d 5 h 15 m 10.5 s in Kerbal days. If it does, then the orbital velocity is the same. 

[Spicat]

29 minutes ago, MechBFP said:

I think there is a bug report about that, but the search on this forum is completely useless garbage, so good luck trying to find it. 

Numbers being wrong on the tracking station or a different one?

[Jeq]

1 hour ago, MechBFP said:

In any case Minmus should complete 1 full orbit in 49 d 5 h 15 m 10.5 s in Kerbal days. If it does, then the orbital velocity is the same. 

Orbital velocity seems to be same. 

[Superfluous J]

Did you check when Minmus was in the same place in its orbit? Minmus' orbit it tilted and eccentric*, and that could matter enough to skew a test.

Could you take screen shots of both maneuver node, with all the UI elements up? And in KSP2's case clicked on so they actually show things? I'd say do it with Minmus targeted so you can see its orbital elements on the map as well but I don't know how much info that gives offhand, even in KSP1.

*how have I made it through over a decade of playing with this misinformation in my brain?

Edited December 13, 2023 by Superfluous J
Factual error

[MechBFP]

2 hours ago, Spicat said:

Numbers being wrong on the tracking station or a different one?

I think I am thinking of numbers being wrong on the tracking station now that you mention it. 

[Superfluous J]

Okay I spent way too much time getting these.

Looks about the same to me.

[18Watt]

8 hours ago, Superfluous J said:

*how have I made it through over a decade of playing with this misinformation in my brain?

I thought it was eccentric as well.  Huh, I am wondering the same thing as you.

[Jeq]

I made further investigation on this, i decided to eliminate all variables, met minmus just at inclination point, exactly 46400km apoapsis.

  Map top view.

Nose going prograde and minmus as target, waiting for maneuver node and everything matched perfectly.