Time Warping Destroys Rotating Craft with Powered Washer

[GHrynk]

I used the Standard Docking Washer to create a rotating hab section on a spacecraft. More specifically, two hab modules on the ends of booms (about 20t total rotating mass), with one powered washer behind the hub, in front of the majority of spacecraft mass (about 120t non-rotating), along with a counter-rotating washer for a docking port module at the very front. I set both washers to relatively low speed and acceleration so SAS modules on non-rotating section could counteract torque during spin-up. Under physics warp, it performs fine. When exiting time warp, the spacecraft twists itself apart and slowly flies to pieces.

I repeated this with the unpowered, free-moving, washer and used monoprop engines to spin up the hab section (I kept the docking port powered). As expected, the hab section stopped rotating when entering and exiting time warp and gave no indication that torque forces/rotational energy were being re-introduced in a destructive manner. The powered, counter-rotating docking section survived, likely due to low mass.

If the relevant rotational momentum information or washer spin-state/position cannot be preserved going in and out of time warp to prevent destruction of craft, can the powered washers be tweaked to re-start (and subsequently accelerate) from motionless state when coming back out of time warp so that there's no sudden conflict of physics? If that's infeasible, can powered washers be made to automatically turn off or temporarily behave as free-moving washers after exiting warp until they can be safely re-started via the Toggle Movement buttons?

EDIT: I'm using KSP 1.2.1.1604 with IR 2.0.7 and IR Legacy Parts.

EDIT 2 - Additional weird effects observed: I tried mitigating the above problem by putting a free-moving washer between the main spacecraft and the powered washer, with Z-1k batteries as spacers. I only turn on auto struts to keep the free-moving spacer locked during spin-up; disabled auto-struts when rotation achieved. When undergoing time warp cycle to 1,000,000x, spacing of parts gets out of whack - the center of free-moving washer rotation becomes offset about 20%. Re-loading the game doesn't return everything back to center. Without doing any spin-up or auto-strutting, the free-moving washer starts off with a slight (about 5%) offset. When time warping to 1,000,000x, the washer is both offset and appears to have separated into two disks, with a noticeable gap, over 10% of washer diameter. I've tried turning off autostruts and rigid attachments, as well as flipping over and re-seating the washer. The effects appear to kick in only when going to time warp, and get most pronounced at the highest warp levels. I've tried taking the majority of the weight off the top (removed hab section booms), then launching and cheat-orbiting to space. Even with the mass of just the hub, both washers appear to separate and/or offset themselves when time warping, and won't revert back.

[drGarbinsky]

+1 let me know if more details are needed

[drGarbinsky]

2.0.8 appears to have resolved this. I flew the same craft to minimus with our parts drifting apart.

[ZiwKerman]

There is still a problem on very high Kerbol orbits (near Eeloo), so use carefully and create a hard save before missions to avoid frustration.

…

On Mon, Dec 5, 2016 at 4:06 PM, drGarbinsky ***@***.***> wrote: 2.0.8 appears to have resolved this. I flew the same craft to minimus with our parts drifting apart. — You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub <#133 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AKuLcCScvG-vA4J8CbVXdXwNCptkBZHPks5rFDZogaJpZM4Kwm5s> .

-- Best regards, Stepan Andreev

[GHrynk]

Closing after apparent resolution with IR 2.0.10 on KSP 1.2.2.