RENAMED - KJR Exerts "Phantom Acceleration" on Larger Vehicles in Mun Orbit w/ Physics Active

[Srpadget]

EDIT: Original post heavily edited to reflect actual issue after more troubleshooting

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Issue: Kerbal Joint Reinforcement causes loaded (i.e. physics active; no warp, and either focus vehicle or within physics range) vehicle to experience "phantom" acceleration in Mun orbit; larger vehicle (with greater KJR 'stabilizing'?) has larger acceleration. 50-60 ton vehicle accelerates on order of 0.1 m/s2, sustained. 'Stably orbiting' space station in 12km circular orbit can drop Pe to below Mun surface, causing impact with surface in under 1 orbit period; or conversely, boosting Ap by > 10km in a fraction of an orbit period likewise.

Mods Installed:

Kerbal Joint Reinforcement 3.0.1 ONLY (all other mods removed during troubleshooting)

To reproduce: Build vehicle with floppy parts and/or long/thin (the sort of vehicle which really wants to have KJR installed). Place in low Munar orbit (10km circular to 20km circular; unknown if effect extends noticeably to higher orbits.) Verify vehicle has no engines activated (i.e., "Deactivate Engine" selected for all attached engines, RCS off). Focus as active vehicle, turn off warp. "Phantom" acceleration will act on vehicle. Record Ap/Pe once every couple minutes. Note how Ap/Pe changes. Sometimes accel, sometimes decel; similar to the tiny phantom acceleration in low Munar orbit in stock, but effect is greatly magnified.

I have seen 12km circular (Ap - Pe = 100 meters or less) orbit degrade to Pe < 0 and subsequent lithobraking in less than one orbital period. Likewise, I have seen 18km circular orbit raise Ap to > 30 km in a fraction of an orbit (I shut down at that point; Ap was still increasing).

Control case: same vehicle, same Munar orbit, but with KJR removed. Note minor "drift" of Ap/Pe, which 'jitters' within a few meters around a more-or-less stable median, but the 'jitter' is more or less random and the momentary effects cancel over the longer term such that orbit stays 'essentially' unchanged over time.

Output log and quicksave of example (smaller vehicle docking with larger station, which drives the point home as the smaller vehicle has to thrust along a single vector repeatedly in order to "chase" the larger station just for stationkeeping) follow in next post.

Edited February 10, 2015 by Srpadget
Retitle to reflect actual issue after troubleshooting

[Srpadget]

Example of issue: Rendezvous/dock of smaller Mun lander with larger orbital station. Forced the rendezvous/dock with a combination of staying in warp to a couple hundred meters followed by excessive RCS usage/constant corrections during proximity operations. Station began in orbit of approx. Pe 18km, Ap 20km, but by the completion of docking the Pe had reduced itself to approx 12km (Ap still ~20km). Output log from end of that session here: https://dl.dropboxusercontent.com/u/36651676/output_log_2.txt

Quicksave file from near beginning of docking maneuver: https://dl.dropboxusercontent.com/u/36651676/Munar%20dock%20bug.sfs

(Note: this quicksave starts with focus on the wrong vehicle; it was not originally intended to troubleshoot this issue. Shift focus to "Flying Dutchman" ship in Munar orbit. Note that originally intended rendezvous is already hosed, and closest approach is about 1.5 km; it had been 0.1km closest approach when set up.)

Edited February 10, 2015 by Srpadget
Rewrote post to reflect actual issue after more troubleshooting