Orbital Decay? Why?

[VelRahnKoon]

Hi all,

I saw the weekly goal of going to the Mun, so I decided to give it a try. Everything is fine until I circularize around the Mun. At that point, my PE starts to steadily drop. No RCS on the craft, does it with engines enabled or disabled. Reloading a save or changing to the VAB or Tracking Station doesn't help either. If I quit the game and come back in, I will usually have a VASTLY different set of orbit numbers than when I quit (i.e. initial circularization to a 15 x 15 km orbit, but when I reload I get 32 x 3 km or something equally whacked). I don't know why it's happening but it seems to be the SoI change from Kerbin to the Mun that triggers it, as any maneuver I've made around Kerbin doesn't cause the PE to start dropping once I finish the maneuver.

This has happened through multiple campaigns and multiple ships. I have even uninstalled and reinstalled the game, but no dice. Anyone have any thoughts?

 

Specs:

Processor    Intel(R) Core(TM) i7-5820K CPU @ 3.30GHz   3.30 GHz

Installed RAM    32.0 GB

GPU:  EVGA GTX 1080
 

Running the game at 1920x1080 with med./low graphics settings. Not seeing much in the way of stuttering, etc.

 

Thanks in advance

[Klock]

I'm having similar results on 0.1.1 version of KSP2.

PC stats:

• AMD Ryzen 7 1700X (8 core, 3.4GHz ...old somewhere above 50% between minimum and recommended CPU)
• Radeon RX 7900 XTX
• RAM 64GB

So we're at least having similar experiences on different hardware, likely removing that as a variable.

I launched an over-built Apollo-style lander & command module mission, so I'm using the 2-seater lander and the 5 seater command.  I've got some instability on the lander, probably because I built it "upside down" in the VAB on top of the command module...was able to work around that by turning off various stabilizing modules.  Undocking was rather forceful, but didn't affect anything negatively.

Landing manually  was no chore, surprisingly did it first time having not touched KSP1 in a while and back then I used MechJeb a lot.

Re-orbiting was a bit harrowing as I had had a prior mission take on a mountain and lose, so I'm not entirely sure I trust the PE / altitude values...settled on ground altimeter and at least I know when things are bad.

I'm now stuck trying to do the return mission, docking the command module with the lander.

Originally was at about a 10x10 orbit on the lander and a 26x20 orbit on the command module...after getting frustrated with the mechanics, I moved the command up to 60x60 and the lander to about a 20x20. 

At the 10x10 orbit, I thought it was some weird bug or maybe the introduction of some nominal dust "atmosphere" affecting my PE decaying on the lander.  After every time warp, I'd go from a roughly circular orbit to a crash trajectory.  Confirmed RCS and engine were off. 

Now that I'm in the 60x60 commander / 20x20 lander orbits, I'm still "chasing my PE/AP" points.  I add a maneuver node at the AP or PE and then they start "separating". 

[GalileOh-No]

Are you trying for a low orbit?

Something you may want to try, I noticed a similar situation around Ike last night where if my orbit dipped below 30 km, it would start to decay, almost like I was in atmosphere. Above 30 km? Static. Try raising your orbit if any of this rings true.

Again, this is anecdotal and a data point of one. Your mileage (or worse, periapsis) may differ!

 

Edit, just read @Klok@s post and yeah, similar situation where I had an Apollo style vessel. Not sure if that contributes to the issue or is coincidental.

Edited March 30, 2023 by GalileOh-No
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