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Acceleration During Time Warp Doesn't Work at Times, No Matter the Thrust (After 0.1.2.0)


KUAR

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Reported Version: v0.1.3 (latest) | Mods: none | Can replicate without mods? Yes 
OS: Windows 11 Pro | CPU: Intel(R) Core(TM) i7-8750H CPU @ 2.20GHz 2.21 GHz | GPU: GTX 1050 Ti with Max-Q Design | RAM16.0 GB (15.7 GB usable)

 

I have a small craft with a DAWN Xenon engine. It's powered by 3 x Gigantor solar panels in full view of the sun. I encounter two bugs:

  1. Under timewarp, the engine no longer provides any thrust. The orbit, which changes as expected when at 1 x timewarp (approx. 0.06-0.07 m/s2 and an according change to AP/PE), appears to be "on rails" when under any degree of timewarp 2 x or greater.
  2. Potentially related, so including in the same bug report; also under timewarp, unusual behaviour of the EC resource is noted. When at 1 x, it behaves as expected (remaining full throughout as panels are generating 3 x the demand from the DAWN). When at progressively greater timewarp, the EC value drops by an amount exactly equal to 0.2 x the timewarp! That is to say, at 10 x timewarp the EC is 203/205; at 50 x timewarp it's 195/205; and at 1000 x timewarp it's 5/205.

 

Included Attachments:

BuggyCraft.zip
 

[Anth12 Edit: Two Main Causes:]

 

 

Edited by Anth12
Change of title + Adding additional information
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Reported Version: v0.1.3 (latest) | Mods: none | Can replicate without mods? Yes 
OS: Windows 11 | CPU: 12th Gen Intel(R) Core(TM) i9-12900H | GPU: 8.0 GB | RAM16.0 GB

 

I created a small satellite for fun and launched it into a rough 1000 km orbit of the Mun. The satellite consists of the 100G Relay Antenna, four gigantor XL medium solar arrays, the drone core command unit, the small 0.70 ton xenon tank, and four ion engines. After deploying, I planned a trip to Minmus, and the burn indicator told me it would be a 11 plus minute burn. Therefore, I started my burn and started to time warp. However, when time-warp began, my orbit immediately stopped changing. I started and stopped time warp several times to verify this and every time it kept stopping my orbit from changing. Every time, I had the audio and the visual of the ion engines firing. I have not tested other engines for this problem yet.

 

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Edited by Anth12
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Reported Version: v0.1.3.1 (latest) | Mods: none | Can replicate without mods? Yes 
OS: Windows 10 Pro 64-bit | CPU: AMD Ryzen 7 2700 Eight-Core Processor | GPU: NVIDIA GeForce GTX 1660 | RAM32GB

 

Specs

Spoiler

image.png

Severity: Med

Frequency: High

EDIT: 1.2.0 was the last working version, I was incorrect.

I'm running a low thrust nuclear xenon cruiser. In 1.2.0 it worked perfectly under timewarp, (barring the inability to hold prograde during timewarp) and in 1.3.1, is now unable to thrust under timewarp.

Where before it was possible to perform a multi-pass boost out of a parking orbit, by time-warping until the prograde drift got too serious, dropping warp, realigning, and repeating until you could get high enough to warp to target, now it's effectively non-functional unless done without timewarp at all.

Setting the throttle to full causes light, steady, controlled thrust as expected, allowing for a slow climb. Timewarping places the vessel on rails and stops the acceleration and orbital change, but still consumes resources like charge and xenon. 

This change makes brachistochrone ion spacecraft impossible again, not because of a lack of parts, but because of no thrust under timewarp making the waiting times infeasible. In 1.2.0, the following vessel was capable of direct transfers to Eeloo and Moho on the same tank of gas, and possibly a Grand Tour, without exploits:

image.png

Now, however, it remains capable of doing so, but the thrust maneuvers would take literal days of real time.

Note that the vacuum stage of the Princess Peach has a TWR well below 0.001, with a dV of 44.4km/s:

image.png

Recommended fix: Do not look at thrust values to decide if a vessel should be placed on rails for the sake of preventing orbital decay. Look at the throttle instead. If throttled up above 0 and possessing fuel and active engines, the vessel should, under all circumstances, be subject to physics.

 

Included Attachments:

PrincessPeach.json

Edited by Xheotris
I was incorrect about the last working version. It was actually 1.2.0
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  • 4 weeks later...

Reported Version: v0.1.3.2 (latest) | Mods: none | Can replicate without mods? Yes 
OS: Windows 11 | CPU: i9-11900k | GPU: RTX 4060 | RAM32GB

 

You would expect the trajectory prediction to change (and so the apoapsis) even during time warp during acceleration.

However, while the delta v decrease and the time progress, the trajectory doesn't change.

To replicate the bug I just recorded my gameplay session (end of the message).

There are also others bugs that can be seen in the video, the rocket tends to go to the North for no reason (there was fins and a medium stabilizer), moreover, when timewarping, the Kerbal panics for no reason.

I hope this bug report will help, if further help is needed my discord name is xavbell.

Since the video is too large to be directly uploaded, here's a youtube link: 
[Anth12 Edit: Changed youtube link to start just before the issue happens]

 

Included Attachments:

Player.log

Edited by Anth12
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  • 2 weeks later...

This is definitely still a problem.  Though I think the cause might be a number of other related issues.  I just tried to accelerate a Dawn/Xenon based craft to high speed to see if that situation is still as bugged as I remember it being.  And yes, it is.

I actually had two different outcomes.  One that I think I've seen very rarely in the past, and another that seems to happen nearly every time.

On the first attempt I launched a vessel with nothing but the smallest probe core, a single Dawn engine, the largest Xenon tank and two Gigantor solar panels.  I got this craft out of Kerbin's atmosphere and began accelerating prograde.  This time when I started time-warping I was actually still able to accelerate.  But, other things were going wrong.  Xenon fuel wasn't being consumed.  The craft reached something like 70000m/s before the solar panels were too far from Kerbol to keep powering the Dawn engine at full throttle.

On every subsequent attempt, with the same vessel, and a variant with the second smallest Xenon tank, things went very differently.  As soon as I would start time-warping while my craft was already accelerating, the acceleration would immediately halt.  I was able to tell that it had halted because my apoapsis stopped rising.  As soon as I stopped the time-warp, acceleration would resume.  On these runs I would also notice something else that definitely shouldn't have been happening.  The electric charge behavior would be... wrong, in a way that's hard to describe.  Here's a link to another bug report that describes it in detail: Electric Charge Generation + Dawn Engine = Incorrect Battery Behavior

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Reported Version: v0.1.3.2 (latest) | Mods: none | Can replicate without mods? Yes 
OS: ASUS Tuf Gaming A15 | CPU: Ryzen 7, 4800H | GPU: Nvidia GeForce RTX 3050 | RAM16GB

 

Trying to stop my probe from crashing into Jool. I've noticed that when engage the ion engine and try to time warp, even at 2x time warp I lose all thrust. The thrust gauge is at 100% and it is still consuming electric charge. However I can see no change in my apoapsis altitude unless I turn off time warp and leave it at normal speed.

Edited by Anth12
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I experienced the same issue shortly after KSP2's release. Maybe extremely low acceleration is getting rounded to zero under timewarp. It would be interesting to try to recreate this with other small engines on extremely massive craft such that the acceleration is comparable.

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Did this a few patches ago closer to release based off other user posts with similar issues of fuel consumed and no orbit change and that seemed to be the case with methalox engines as well. I can't tell you the exact value for designing ships to not have this issue but for the case of testing earlier i changed the thrust limiters down from 100% where warp was fine to around 5% it created the bug above with time warp. Maybe Devs can give a better answer to around when it is seen so you can design towards the limit? In the meantime i avoid the Ion engines and am careful for TWR of hydrogen cores for longer missions

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I ran into quite a few time acceleration issues recently when I tried ION.

My launch craft exited orbit somehow, and this - the thrust had no effect when accelerating time.

I could've sworn it still worked in lower orbit (~120km around Kerbin) but when I got a bit of space to open her up it just... didn't.

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Reported Version: v0.1.4 (latest) | Mods: none | Can replicate without mods? Yes 
OS: Windows 10 pro 10.0.19045 N/A Build 19045 | CPU: Intel Core i7-2600 | GPU: NVIDIA NVIDIA GeForce GTX 980 Ti | RAM16 GB Generic Memory

 

My first 5 minutes in 1.4v.
Ion engine satellite on an orbit around Kerbin.
Thrust 100%. When fast forwarding - game keeps telling that it is 100% throttle but no changes in Orbit nor Velocity.
Then after using SAS and pointing into backward directions (losing V and lowering orbit) - magically it worked with all time speeds for some 20-30 seconds.
Then... it stopped again changing the orbit in any way. Never returned to work again. 
Closed the game and will not play it again until next patch.

Edited by Anth12
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Experienced something like this both whilst trying to escape Mun orbit and when capturing around Minmus. Each time I'd set up a manoeuvre node and while making the burn had tried time warping. I'm not exactly sure what was going on but it took much more fuel to capture around Minmus under time warp than when I reloaded and didn't use time warp.

The clock ran out on the manoeuvre node well before I'd escaped Mun orbit or circularised around Minmus. Something not quite right.

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