Rendez-Vous relative speed wrong

[cami]

KSP Version: v0.24.2.559 Linux 32-bit Steam [Note: the real OS is Linux x86_64, but Steam launches KSP 32-bit], and also

KSP Version: v0.24.2.559 Windows 32-bit Steam [Note: the real OS is Windows 7 64-bit, but Steam launches KSP 32-bit]

What Happens: Target flies away at > 50m/s although relative velocity is 0.5 m/s

Mods / Add-Ons: None.

Steps to Replicate:

1) Load save file.

2) Switch to Kyle 1 or start any other rendez-vous maneuver.

3) When close (1–10 km) and slow, toggle between warp 1x and 5x and watch the difference.

Result: perceived relative speed (~100 m/s in example) does not match indicated relative speed (0.5 m/s in example) at warp 1x. All fine (both 0.5 m/s) at warp 5x.

Fixes/Workarounds:

- You can try to catch up if you have plenty of fuel.

- As long as Warp > 1x the bug does not appear.

- In high orbits (very little gravity), try to match your orbits by normal means. Once you get close, set relative velocity to 5 m/s (or whatever your favorite approach speed) straight to the target (this is important because you will be far away). Activate time warp as soon as aligned. You may want to choose faster than 5x because of the significant distance (this is where we need low g). You can do RCS maneuvers but stay above warp 1x as much as you can. Once you reach about 500 m distance, the problem disappears and you can dock normally at warp 1x.

Other Notes/Pictures/Log Files:

- The problem disappears below about 500–1000 m distance to the target

- Steam was started in a shell with export LC_ALL=C and export LANG=C and KSP was launched from there.

- Reproducible with all rendez-vous maneuvers (all crafts all orbits) within the saved game.

- Images Link: http://goo.gl/FU3EzZ

- Log File: http://pastebin.com/mWNWq8ua (note the "dT is NaN!" warnings)

- Save file: http://www.file-upload.net/download-9464743/quicksave--45.sfs.html (0.67 MB)

- Craft File: http://pastebin.com/CnVRsnir (The example rendez-vous is between the two stages that have a docking port)

Update Sep 2^nd, 2014: the problem also disappears below ~500m distance. Added Workaround exploiting warp > 1x in order to reach that distance. Added Windows platform.

Edited September 2, 2014 by cami
Additional conditions for occurance. Workaround. Also on Windows.

[vexx32]

To be totally clear, where you're seeing the bug, the navball is displaying target​ mode, correct?

[cami]

Yes See the screenshots, too. As soon as warp is active the target also stops flying away, I exploited this for a partial workaround already. This is what made me suppose it's not the relative speed indicator that is wrong, but rather the perceived relative speed itself.

[narnianpony]

I have the same problem, the relative speed makes no sense between my 2 vessels: KSS-1 and KSS-Mission2

As you can see on the video:

Using the KSS-Mission2 their distance becomes bigger, switching to KSS-1 without changing anything (not burnout, nor rcs, just changing the vessel) the distance becomes smaller. What is happening is: the used vessel is the faster one.

KSP Version: 0.25.0 Build 00642 Linux 64-bit, KSP 64-bits and 32-bits (tested both) using Steam

Save folder: https://www.dropbox.com/s/mtwo0mjlb8iuut5/Agustin.zip?dl=0

Edited October 14, 2014 by narnianpony