Flight Accelerate under Timewarp still not working in some cases (Often in Large SOI's)

jclovis3 · December 22, 2023

What Happened:
While taking off from Minmus in a Northly direction, I used the time warp and noticed my Ap stopped changing. Fuel was still being consumed. The trajectory arc was also not changing.

Evidence:
I tried loading from a quick save and even restarting and this bug persists, so I'm attaching the quick save.

Video:

Included Attachments:

BuggedSave.zip

Edited June 13 by The Space Peacock
Added video and reformatted text.

The Space Peacock · January 3

@krbvax merged your report

Anonymous Bug Reporter · January 3

Happens seemingly randomly after entering a new soi. Solar panels in full sun, batteries fully charged. Throttle doesn’t seem to make any difference. Thrust animation and sound appear, but 0 thrust while time warped. Thrust stops above 1x and returns at time warp 1x. Fresh ksp2 install with no mods. Save/restart makes no difference. Sometimes fixed by exiting vessel to vab, tracking station, etc but not always.

Included Attachments:

macson_g · January 6

I experience the same in 0.2.0.0.30291. (Windows 10 (64 bit))

I was able to depart Kerbin, but I'm unable to perform the injection burn at Dune.

TFA3393 · January 6

Probably my most disliked bug post 0.2.0. Ion engines are close to unusable because of this. Only work around I found was to set throttle to below 10 (which was odd) and even that stopped working after a little.

jclovis3 · January 7

One issue I am noticing especially with larger ships is that going into or out of time warp greater than x1 causes a lag as the physics engine is shifting modes. I found more success if I avoid jumping straight into higher time warp cycles until I have successfully made it into x2 and waited for this delay to complete and the clock starts running again. Then I can move up into higher warp factors with no problem.

ittoscano · January 7

Hi, i have had and stil have the same problem, when i burn with xenon engine, if i increase the speed of time, the vessel won t accelerate.

Then if i put time back to 1x, i can ' t decelerate and i have message "cannot move thrust over 1x time" (This is ehat it mean, i don t know the real message because i have game language in italian).

i must to reload the game and everything return working, but i cant increase time speed and it is precisely with that type of engine, which doesn't have much thrust, that it would be useful to have timewarp!!

Anyone havehad this problem and have a solution?

Can you increase time speed with Xeno engine?

Update: this happens when i am in a vessel which was generated from a later stage, when the vessel is exactly the big one that i launch it' s work...

Many thanks..

Edited January 7 by ittoscano

Anonymous Bug Reporter · January 22

Sometimes when you have the engines on to do a manouver and turn on time warp, the DeltaV of the Spaceship wont change anymore although the engines are running and the Ship loses fuel.

Included Attachments:

Ghnuberath · January 24

I can also confirm this bug. I have a probe with 3x ion engines. It was working fine in kerbin orbit up to about 0.8km AP/PE and then suddenly no thrust in time warp despite fuel consumption. I was doing repeated burns to escape Kerbin SOI.

I have definitely noticed this once with nuclear engines as well. On return from Duna I time warped a few intercept correction burns and ended up with vastly less fuel and unmodified trajectories and didn't know what had happened.

T the G · January 27

Yep, this bug makes low TWR craft unusable.

The tips reported here (like switching to VAB/tracking station and back again) don't work for me.

I am now doing a 28 (real-life) hour burn, because I really want to get to Jool with my Xenon engine. With timewarp above 1x, fuel and electricity are being consumed, but the orbit does not change.

I cannot seem to attach my bug reports (generated using KSP2_BugPackager), does anyone know how? (Aside from hosting on e.g. Google Drive and adding the link here.)

darude · January 28

nvm still bugged

Edited January 28 by darude
i was wrong

Anonymous Bug Reporter · January 28

I was trying to do a low sun-orbit using the ion/xenon engine because of the high fuel efficiency. but after activating the engine about 1m-km-periapsis from kerbol and then time-warping i noticed that the time-warp broke and the engine produces no trust. Every time-warp stage is 1x. you cant even do things to the craft as time-warp is over 1x (even at the 1x setting) the number under the time-warp bar that recites the current time-warp speed is always at 1x at every time-warp level.

Included Attachments:

SolarAdmiral · February 3

Reported Version: v0.2.1 (latest) | Mods: none | Can replicate without mods? Yes

OS: windows-11 | CPU: i7-13700 | GPU: rtx-3070ti | RAM: 32,0 GB

I've been doing some Ion probes and I've been getting this. Acceleration under timewarp worked fine at some times, but not at others. When it worked it seemed correct. When it wasn't working, no acceleration at all happened during timewarp even though the ion engine was still using power, the orbit PE didn't move at all. Acceleration started happening again as soon as changing back to x1 speed. It seemed like it didn't work when the probe was heavier. A light Ion probe worked fine while under timewarp. But after editing it, adding a few parts and making it heavier, suddenly it also wouldn't work when warping. Since all the probes only had one engine, the heavier one had a lower acceleration. Maybe this bug is being caused by low accelerations? It did seem like the Ion probes with a higher acceleration were able to timewarp.

Margoth · February 3

(0.2.1) I'm encountering this randomly with Dawn. E.g. I have a number of identical very light probes (sample return pods), one of them bugged out in the above described way after escaping Eve SOI - worked fine while within SOI. Another probe escaped Eve and did a 90min burn just fine under time warp. Reloading and quitting game don't seem to help. Don't know if related, but the AP/PE reported in lower left seem to be bugged too (reported 0m/0m or -2,088km/20,567m)

SolarAdmiral · February 3

~~New observation. I'm tending to find the ions work on timewarp while in Kerbol's sphere, but not while in the sphere of a planet or moon.~~

Nevermind. Satuts was, not working at Kerbin, working in Kerbol SOI, not working at Moho, working at Kerbol SOI, but then working second time in Moho SOI.

Edited February 3 by SolarAdmiral

Anonymous Bug Reporter · February 6

I've not tried this with any other type of engine, but for sure the problem exists with ion engines. I've got a small probe in an eliptical orbit around Eve and I'm using an IX-6315 "Dawn" engine to slowly work down to a circular orbit I'm having to run the burns in 45min intervals but every time I try to increase time warp above 1x, all thrust stops. The animation continues. And it shows Xenon and EC being used, but PE and AP never change.

Something else I encountered on one test run, I let the EC run out completely but the engine never stopped burning and because the engine was using more EC than my solar panels could produce, I couldn't shut the engine down.

Included Attachments:

kdaviper · February 7

I noticed the game would not let me adjust throttle at 1x timewarp after trying to burn under timewarp with these engines.

goatduoduo · February 7

The bug remains unresolved and occurs consistently under specific steps.

1.launch a vessel (especially with ion engine, but other engines still have bug as well)

2.go to an orbit

3.quit game and reenter game

4.control the vessel you launched recently

5.try to burn in time warp

You will see AP and PE do no changes while burining and fuel still consuming as well.

The Aziz · February 11

This better be in the top5 of next KERB marked as fixed and verified for a hotfix. I'm about to give up on the game. Not only burn doesn't do a thing, but also I can't quit timewarp.

val778 · February 28

I have the same issue

This makes ion engines pratically unusable because randomly you are faced with this bug and either have to delete your bugged ship or have to do your 2 hours burn in x1 speed :mad:

Edited February 28 by val778

dolphin263 · February 29

One thing I have noticed is this reliably happens if available delta-v > 64k. It's hard to do that without mods, but with mods can be easy.

20 hours ago, val778 said:

I have the same issue

This makes ion engines pratically unusable because randomly you are faced with this bug and either have to delete your bugged ship or have to do your 2 hours burn in x1 speed

Ah, does your vessel have delta-v over 64k? If so, that's the issue. I forgot about the ion engine, but that has high isp so you probably can get more than 64k delta-v, which is what seems to trigger this.

Edited February 29 by dolphin263

Sun_Serega · February 29

2 hours ago, dolphin263 said:

One thing I have noticed is this reliably happens if available delta-v > 64k

No, it's related but not the trigger. I just explained this bug above.
Basically you need high position or velocity. With how floating point numbers work - this lowers precision, triggering that sanity check.
High position is easy to get, for instance teleport to a high circular orbit above Jool, its extreamly consistent there. I casually reproduced it first try at the end of my mod's demonstration video.

Edited February 29 by Sun_Serega
add link to explanation "above"

ShadowZone · March 3

Situation: retrograde orbit around Laythe. I want to flip the trajectory, so there is a maneuver plan already set in the attached save game. When performing the burn, the game always refuses to do burn under timewarp in this situation.

Being around Jool generally seems to trigger this bug very reliably.

Included Attachments:

ForSci_Bug42.mov

ForSci_Bug42_noBurnUnderTimewarp_logs.zip

Edited March 3 by ShadowZone
Request for merge no longer needed. Thanks!

Spicat · March 3

@ShadowZone, merged your bug report.

val778 · March 3

When burning with ion engines and the orbit is very eccentric (like when braking to enter orbit after interplanetary transfer), time warping while burning with ion-engine doesn't affect the orbit and still consume fuel. Ion engines thus only work in time warp x1, which is a completey game breaking bug because this make low thrust ion engines completely worthless. I can't make a 1 day burn just to orbit my craft around Jool.

Please fix urgently

Included Attachments:

DibzNr · March 4

@val778Merged your report with this post

Flight Accelerate under Timewarp still not working in some cases (Often in Large SOI's)

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