Low Munar orbit deteriorating...

[Chilkoot]

I tried to establish a rather low Munar orbit to visually scan for interesting features on the surface.

HOWEVER, once I establish an orbit around 13km or so, the orbit slowly deteriorates - and it's very repeatable.  I've even launched a second surface observer mission in a polar orbit around the Mun to test, and the same thing happened consistently, and even at a steady, predictable rate.

Is there a very rarefied atmosphere on the Mun now??  Or is this maybe just a bug?  Has anyone else seen this effect?

EDIT:  There is definitely *sometimes drag.  If I "broadside" the orbital plane in my craft, the rate of deterioration increases, where if I take it nose-on, the rate of decrease is much lower.  I'm not sure if the drag is intentional, but it's definitely there.

EDIT 2:  After a reload, it no longer manifests as simply drag.  The AP increases now while the PE decreases, depending on where the craft is in its orbit.  Enabling time warp 2x (or greater) stops the problem.  Def going to log this one as a bug since it's clearly not just an intended, rarefied atmosphere.

Edited February 26, 2023 by Chilkoot

[RaBDawG]

6 minutes ago, Chilkoot said:

I tried to establish a rather low Munar orbit to visually scan for interesting features on the surface.

HOWEVER, once I establish an orbit around 13km or so, the orbit slowly deteriorates - and it's very repeatable.  I've even launched a second surface observer mission in a polar orbit around the Mun to test, and the same thing happened consistently, and even at a steady, predictable rate.

Is there a very rarefied atmosphere on the Mun now??  Or is this maybe just a bug?  Has anyone else seen this effect?

EDIT:  There is definitely drag.  If I "broadside" the orbital plane in my craft, the rate of deterioration increases, where if I take it nose-on, the rate of decrease is much lower.  I'm not sure if the drag is intentional, but it's definitely there.

Haha there's an atmosphere on the Mun?  IS there anything in this game NOT broken?  Good lord lol.

[Razor235]

This happens at Minmus as well, and I think I've noticed it in LKO to a much lesser extent.  None of my missions to other planets survived the bugs before I gave up spaceflight altogether and just stuck to planes, but I assume it happens elsewhere.   I really think its a bunch of math/calculation errors, but the altitudes are always consistently trending downward.  I'd wager it's also related to the violent destruction of vessels coming out of timewarp at low altitude.

[Spazmataz]

1 hour ago, Chilkoot said:

I tried to establish a rather low Munar orbit to visually scan for interesting features on the surface.

HOWEVER, once I establish an orbit around 13km or so, the orbit slowly deteriorates - and it's very repeatable.  I've even launched a second surface observer mission in a polar orbit around the Mun to test, and the same thing happened consistently, and even at a steady, predictable rate.

Is there a very rarefied atmosphere on the Mun now??  Or is this maybe just a bug?  Has anyone else seen this effect?

EDIT:  There is definitely drag.  If I "broadside" the orbital plane in my craft, the rate of deterioration increases, where if I take it nose-on, the rate of decrease is much lower.  I'm not sure if the drag is intentional, but it's definitely there.

 

7 minutes ago, Razor235 said:

This happens at Minmus as well, and I think I've noticed it in LKO to a much lesser extent.  None of my missions to other planets survived the bugs before I gave up spaceflight altogether and just stuck to planes, but I assume it happens elsewhere.   I really think its a bunch of math/calculation errors, but the altitudes are always consistently trending downward.  I'd wager it's also related to the violent destruction of vessels coming out of timewarp at low altitude.

 

Yes, it happened to me too, both on Mun and Minmus. In the case of Minmus, in what started as a low, circular orbit, the periapsis would mysteriously decay into the surface, -- but here's the weird thing --  the apoapsis would mysteriously rise too. This is not consistent with atmospheric drag.

The rocket had no RCS available, and I made sure that the engines were not firing at all, even a little. So I have no explanation for the orbit decay, besides just being a bug, I guess.

[Dman979]

@Chilkoot this sounds like a bug- it'd be helpful if you could report it here: https://forum.kerbalspaceprogram.com/index.php?/forum/144-ksp2-bug-reports/

[Chilkoot]

1 minute ago, Spazmataz said:

but here's the weird thing --  the apoapsis would mysteriously rise too. This is not consistent with atmospheric drag.

Interesting.  Going to try and make some time to test further tomorrow.  I also suspected some kind of propulsion 'leak' (non-zero thrust), but the deterioration for me was the same whether facing prograde or retrograde.

[Razor235]

27 minutes ago, Spazmataz said:

but here's the weird thing --  the apoapsis would mysteriously rise too. This is not consistent with atmospheric drag.

Alright, that makes me almost certain it's connected to the timewarp shenanigans, because that's what the resulting orbit is doing almost all the time.  After dropping out of warp a massive force is applied that always causes the ship to spin, and usually results in parts breaking or being severed, and I end up going from a circular 30x30 orbit to surface impacting/150km Ap in an instant.