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Orbital decay still happening [Landing legs or certain parts interacting can cause it]


NovaRaptorTV

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Reported Version: v0.1.5 (latest) | Mods: none | Can replicate without mods? Yes 
OS: Microsoft Windows 11 Home 10.0.22621 64-bit | CPU: AMD Ryzen 9 5900X 12-Core Processor (24) | GPU: NVIDIA GeForce RTX 3090 (24339MB) | RAM65458

 

I encountered the return of orbital decay after loading a save. As a work around, I managed to activate time warp, but this only solved it temporarily.

I am not sure if it affects other celestial bodies in the solar system.

These are the steps I took after loading:

1-Begin timewarp and then exit
2- Start my power descent(descent burn)
3- record results

 

Included Attachments:

OrbitalDecayAroundMunafterLoadingaSave_logs.zip

SpacePeacockDebugger.json (craft file)

Edited by Spicat
added additional information & files provided by author. thanks!
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Reported Version: v0.1.5 (latest) | Mods: none | Can replicate without mods? Yes 
OS: Windows 10 | CPU: Intel Core i7-1065G7 | GPU: NVIDIA GeForce MX350 | RAM8GB

 

Issue:
Having certain  parts clip in specific ways can still cause orbital decay. The cause for the craft used in this report was narrowed down to the interaction between two antennas.

Steps to Replicate:

  1.  load low_tylo_orbit.json
  2. observe orbital decay happening

              Note:
              the craft was also tested in low Mun orbit, where decay also happened

Cause:
Decay on this craft is caused by the interaction between a 'Communotron DTS-M1' and a 'Communotron 88-88' (both undeployed)

  1. load JUICE_V2.1.json in the VAB
  2. remove either one or both of the antennas
  3. launch the craft into a low orbit around the Mun or Tylo
  4. confirm decay is no longer happening

Image:

Spoiler

the offending antennas:

20231031171901_1.thumb.jpg.cbdf00274b0f473853e06a2f4d0ebfb4.jpg


Video Evidence:

Credit:
Thanks to @Anth for testing, replicating and discovering the cause of this bug

Edited by Spicat
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I want to add on here that I encountered a bug after going on EVA in minmus orbit. The craft's orbit was stable until I took a Kerbal on EVA. After the EVA was complete, the orbital decay bug returned.

1 minute ago, NovaRaptorTV said:

I want to add on here that I encountered a bug after going on EVA in minmus orbit. The craft's orbit was stable until I took a Kerbal on EVA. After the EVA was complete, the orbital decay bug returned.

However, I will make this a separate report.

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  • 1 month later...

Reported Version: v0.2.0 (latest) | Mods: none | Can replicate without mods? Yes 
OS: Windows 11 | CPU: Intel i9-9750H | GPU: RTX3060 | RAM32GB

 

Was launching from Minmus and encountered some nice orbital decay - only happening at 1x timewarp. Decay continued until ~9-10km above the surface.

The craft had landing legs, but no ladders & the Kerbal was inside the capsule (not on EVA).

 

Workarounds:

- Use timewarp until altitude is >10km

 

Included Attachments:

 

DECAY.json

Edited by The Space Peacock
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Reported Version: v0.2.0 (latest) | Mods: none | Can replicate without mods? Yes 
OS: Windows 10 Professional | CPU: AMD 5800x | GPU: Zotec 3070 with improved fans. | RAM64GB CL14

Underestimated dV for landing on the mun and the lander (compact probe) came up short and was left in orbit around 4000 PE / 14,000 AP but after one full orbit of the Mun I noticed it's orbit had shifted significantly. AP had gone up while PE was going down (~3000PE/15,000AP), eventually crashing at around 1500 PE / 17,000 AP (PE not Zero as that's sea level and I cliped a hill). Quite Odd and undesirable.

Included Attachments:

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Reported Version: v0.2.0 (latest) | Mods: none | Can replicate without mods? Yes 
OS: Windows 11 Pro 64-bit Build 22621 | CPU: i9-13900KS | GPU: RTX 4070 Ti | RAM64 GB

I've done about 10 missions in 0.2.0.0, and I've seen my orbit decay slightly after taking off from the surface of both the Mun and Minmus.  In each case, I lifted off and burned for around 10 seconds, just to get a decent Ap of about 20 km, and then cut the engines.  The Ap started decreasing slowly as the craft drifted upward.

If I activated 2x or 4x timewarp, the decay stopped.  If I went back to 1x, the decay resumed.  When I reached a high enough altitude that the game enabled 10x timewarp, the decay stopped completely, even if I left it at 1x.

I'll try to get a video if it happens again, but I wasn't recording at the time.

Included Attachments:

MunLander.json

Ksp2.log

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Reported Version: v0.2.0 (latest) | Mods: none | Can replicate without mods? Yes 
OS: Windows 10 | CPU: Intel i5-11400F @ 2.60GHz | GPU: NVIDIA GeForce RTX 3060 | RAM16GB

 

Severity: Medium

Frequency: Can be reproduced with same vehicle every time the save is loaded

Description: Apollo style Mun lander with an orbiter and lander docked together lose altitude when save is loaded. Undocked lander loses more altitude after being undocked, game saved, then save reloaded.

 

Included Attachments:

Desktop2023_12.21-08_41_35_03.mp4

KBKGMunLandingVehicle.json

 

Edited by 6ar6oyle
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Reported Version: v0.2.0 (latest) | Mods: none | Can replicate without mods? Yes 
OS: Windows 10 | CPU: Ryzen 5 3600 | GPU: GTX 1080 | RAM32 GB

 

Testing around Minmus showed that the orbital drift bug was still present. It appears to have been fixed around the Mun as it was still an issue until the 0.2.0.0 patch, but Minmus and potentially other bodies remains an issue.

In looking at exactly what kind of force vector was being applied, you can verify it through the video that it's consistent with a "radial-out" force pushing away from the body's surface. Estimating the rate at which the Apoapsis and Periapsis increase and decay respectively, it's consistent with a constant outward vector equivalent to the surface gravity of the body. Instead of pulling inward and creating a stable orbit, there's an outward force instead, pushing the craft away constantly, causing this radial-out motion.

The patched conics indicate that the craft is orbiting, which suggests a correct inward pull of gravity (or at least on rails). But this additional outward force is destabilizing the orbit.

 

Included Attachments:

KSP2_orbital_drift_bug.mp4

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I don't know if that can help, but I have orbital decay around Minmus right now at 12700meters above sea level, 32km AP (and rising) and 8500m PE (and falling at about 15m/s), but it STOPS when fast forwarding. I've just decoupled my ship, and the two "ships" still suffer from it (A stayputnik with a communotron 16-S, a Z-100 and a OX-STAT. On the other ship a TD-12, a Mk1 "Tin can", a Mk16-R, a HS-125, a TD-12, an AE-FF125, two CBS-125 (containing a Z-200, a RGSCM-01 and aASCM-b), a FT-T400, a FL-T100 and a LV-909)

Edit: I want to add that when I left 4x zone (The height where you can timewarp at 4x max), the decaying instantly stopped

Edited by Leocrabe225
I have new information
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Seeing some oddities on a 'twig' probe with landing legs, at anything lower than 15km circular orbit on Minmus. This also seems to cause increased difficulty with landing my rocket and making my SAS/protograde landing burns go crazy because it can't figure out what is '0' velocity when at close to 0km/s and a few hundred meters above the surface

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Also Experianced this orbiting Minmus, but only when under 10km (and to a far lesser degree until the lander seperated from the ship)
So this effect is affected by the total weight of the craft and the gravity of the celestial object.

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I experienced this around Ike. I raised the apoapsis to about 40km, with the apoapsis about 10km. I was waiting to get to the ascending node to get coplanar with my return vessel, but noticed my periapsis was chasing me. I wasn't sure if it was something to do with Duna's gravity, or a bug. So i switched to the return vessel which was in a ~50km circular orbit and observed the orbit was stable. When I switched back to the landing craft it was on a crash course, and just about to reach the apoapsis of about 20km, which is nothing like the 10km/40km orbit it had 20 seconds ago. Luckily I made a quicksave on the ground of Ike which I reloaded. Upon launch it was doing the same thing again, so I decided to burn straight towards an intercept with the return craft. It seemed like once I got above 30 km or so, the orbital parasite seemed to die, and Jeb, Val and Bob made it safely to the return vessel. Praise Kerbol.

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Reported Version: v0.2.0 (latest) | Mods: none | Can replicate without mods? Yes 
OS: win 11 | CPU: I7 | GPU: rtx 3080 | RAM32

Orbit decays, apoapsis and periapsis loses altitude.

This happens while vessel is currently allowed to accelerate only to x4 timewarp speed and when timewarp isn't used.

At video this happens at Gilly.

Included Attachments:

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Just happened to me in a 12km orbit around the Mun and subsequent descent. It was very unpleasant to realize that my orbit was decaying through no fault of my own, and that reloading a save made my orbit worse than it had looked when I made the save. Will try again with a 20x20km orbit and see if it reoccurs.

Yup, I set myself into a stable 21x21 km orbit around the Mun, and after loading another save and loading back, I was greeted with the sight of my craft spinning wildly and my PE having dropped to 3km (although also on a collision course somehow). Something is very wrong with how orbits are calculated.

Edited by TROPtastic
did additional testing
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Reported Version: v0.2.0 (latest) | Mods: none | Can replicate without mods? Yes 
OS: Windows 10 Home 22H2 | CPU: AMD Ryzen 7 7800X3D | GPU: MSI Gaming GeForce RTX 4080 16GB GDDR6X PCI Express 4.0 | RAM128 GB DDR5-6000

To reproduce:
Enter Gilly Low Orbit with Pe/Ap both below 6 km. I tried to set them to 5,500 m when I discovered this bug. Reduce thrust to zero and ensure RCS is turned off. Toggle SAS on or off as you notice what is happening.

What happens:
Ap begins to rise and Pe begins to fall, making it impossible to maintain a circular orbit under 6 km for a full lap to perform orbital scans that require unique biomes at low orbit (such as with the science lab). SAS on or off does not solve this problem. I retracted solar panels as well to see if they were behaving like solar sails (is that even implemented).

What should happen:
Ap/Pe should not change. The orbit should be stable around Gilly as there is no atmosphere, or if there even was, both should go down.

Evidence:
Attached save file is of the lander going in to discover the low orbit parameters needed to descend my orbital science lab, which is still attached to the transfer module in orbit of Gilly. The lander will of course be headed to "The Crater Conundrum" marker but can be used to test this bug.

Notice:
Warp speeds are extremely limited around Gilly so plan to spend a lot of time if you continue with this save.

Included Attachments:

BugPhantomForcesatGillySaveFiles.zip

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