What do yellow time numbers really mean?

[strider3]

On 2/10/2020 at 1:10 PM, AHHans said:

@strider3: If you type the "@" symbol followed by the (the first characters of) a name, then the forum software will give you a selection of names that start with the already-typed characters. If you select one of them like that then that person gets a notification, making it easier to quickly reply to a question.

About the reaction wheels: I meant the placement of reaction wheels in relation to the control point. SAS only considers the movement of the control point when deciding which control input it generates. So if you have the control point on one side of a bendy part of, e.g., a station and reaction wheels on the other side of the bendy part, then any bending around that part will be amplified by SAS(*). Not putting the reaction wheels at the ends of a craft helps against this, but IMHO switching off SAS when possible or careful selection of the control point when it isn't is better. On space stations I have this kind of problem with docked craft: they have their own reaction wheels, and the normal (or even worse the junior) docking ports are quite bendy. So leaving SAS on for such a station is a recipe for disaster. And just today I had a similar problem with a launching rocket: I forgot to switch the control point to the probe core below the bendy part (the axle of the spin-gravity section), so SAS was using the capsule on the top of the rocket as reference with nearly all the torque coming from the engines at the bottom of the rocket...

(*) If you have the BG DLC, then you can make a demonstration case: have a docking port, some girders, some hinges with little or no torque (and no damping), some girders again and a command capsule with reaction wheels in a line (with batteries etc.), cheat that into orbit, switch on SAS to prograde (or whatever), and then select either the capsule or the docking port as control point and wiggle it around somewhat.

@AHHans I usually keep my station's reaction wheels at a very low torque setting...10%. I always disable the reaction wheels and RCS on a docking ship right before the docking occurs. This seems to allow the station to maintain it's orientation with SAS without any undue wobbles caused by the docking ship. This has worked well with the "death wobbles" and I haven't suffered from them in awhile. If I'm understanding you correctly, the best control point, for a station such as mine, would be the central hub? Would the central hub also be the best "root part"...with everything else grandfather auto-strutted to it? I've had issues with the entire auto-strutting and root part...but I now believe that the weldable ports are probably the largest cause of all these issues. If I haven't already mentioned, I am rebuilding the exact same station with the only difference being stock senior ports as opposed to the weldable ones. Hopefully this will verify, once and for all, that these weldable ports have..."issues"...at least in my game.

On 2/10/2020 at 3:20 PM, swjr-swis said:

It's a Rockomax X200-32 LFO tank, with a Sr port at either end. Except instead of attaching it to the node, you attach it on the side, then use the rotate and offset tools to meld them into the orange tank.

The central hub does the same trick twice, starting from a Rockomax X200-32. rotate so you got all three axes covered, then offset them into each other until their centers overlap, et voilá: a 2.5m center hub node with six Sr ports to build out from.

  Reveal hidden contents

The docking arms are build by radially attaching  a Rockomax X200-32 LFO tank, offsetting it into the orange tank until the center lines cross, then placing Sr ports at either end.

The same trick times two creates the central hub, except the starting tank is the same one.

Attach radially, rotated so they each cover one of the three axes, then offset until their centers overlap.

There you go, a full stock 2.5m center hub node.

Here's the link to the craft file (made in 1.3.1, should be compatible with later versions): https://www.dropbox.com/s/2x2eaebr34pp5hq/Strider3-teststation.craft?dl=0

@swjr-swis I have never tried...or even knew...this type of construction could be done! Do you find an advantage to making the station this way? Obviously, a lot of fuel/lOX storage...but how stable and solid do you find these "melded" parts to be?

[swjr-swis]

19 minutes ago, strider3 said:

Do you find an advantage to making the station this way? Obviously, a lot of fuel/lOX storage...but how stable and solid do you find these "melded" parts to be?

I find them to be just as stable and solid as regular stack attachments - that is to say, within the parameters of what KSP/Unity physics considers 'solid'. Nothing a bit of judicious autostrutting can't solve, usually.

Clip too many parts together in the same space, and at some point KSP will throw a tantrum and shake it all apart at loading. But then that happens without clipping too, so it's all about finding the happy medium.

[AHHans]

10 hours ago, strider3 said:

@AHHans I usually keep my station's reaction wheels at a very low torque setting...10%.

Well, if the torque of the reaction wheels is still stronger than the "wobbliest" part of the structure, then SAS will still increase the amplitude of the wobble. If SAS gets into a positive feedback loop, then it doesn't matter how much energy gets added each cycle, the energy in the oscillations is still going to increase until something gives. Really, the best solution is to switch SAS off in this case!

10 hours ago, strider3 said:

If I'm understanding you correctly, the best control point, for a station such as mine, would be the central hub?

Well, the part closest to the center of mass that has sturdy connections to all the reaction wheels. So, yes, that would probably the central hub.

11 hours ago, strider3 said:

Would the central hub also be the best "root part"...with everything else grandfather auto-strutted to it?

I wouldn't use autostrut to root at all in a station.

My approach to keeping space stations stable is not to make them more sturdy, but to reduce the forces working on them.

[Norcalplanner]

In my experience, auto struts causes more problems than it solves. Using KJR and turning auto struts off, combined with having one control wheel on the station right next to the root part, means that I haven't had any station wobble issues for quite some time.

[strider3]

I rebuilt the station without the "weldable" Konstruction ports. Nothing has changed...I can dock one set of tanks, one time, then I come within 200 m. of the station with another set...and the station comes apart (without changing my target to a port!!!!!!). I load a save and I can get within 200 m, no problem, I can target the port I want, no problem...but when I dock...the station comes apart. Obviously the Mod is not the problem. This is totally ridiculous. I don't know what's wrong with KSP 1.7.3

In my experience, auto-struts are the ONLY way to keep a space station together. Again...I'm not having "wobble" issues...I solved those several years ago. I'm having large parts of my station just...disconnecting and floating off. No "wobble", nothing to indicate it's coming...it just...happens. It happens when I get within 200 m, then it doesn't. Then it happens when I target a (stock) port...then it doesn't. It happens when my station is within 2k meters...then it doesn't. It happens when I dock...then it doesn't. 

There is no "smoking gun"...I have eliminated all the ones suggested, above. Let me perfectly honest...I'm about over the entire thing, you all realize how much time and effort we spend in our KSP "adventures"...I just don't know if I can continue to have my efforts thwarted for some "unknown" issue? I may consider going back to a previous version of KSP...that actually worked...but, at this time...I am NOT a happy camper.

 

 

Edited February 24, 2020 by strider3

[HvP]

@strider3 I can tell you're very frustrated, and I would be too, but this isn't a problem that most people (or anyone I've heard of) have had with the stock game. I still think it's mod related.

You say you are playing in version 1.7.3 - well, the game has been updated three times since then and if you have installed mods that were built for the newer versions of the game then it can cause all sorts of havoc. Even having a version of module manager that isn't compatible with the game version you are running can break all sorts of things.

As it stands, my only remaining suggestion is to try running a new copy of the game with no mods at all installed. I'm not talking about just not using the parts on your station; I mean that there should be nothing in the "GameData" folder but ones named "Squad." That should tell us once and for all if it truly is a problem with the stock game or not.

And if it IS a problem with the stock game then you should consider updating the game to at least version 1.8.1 which is not only a very stable version of the game, but has a large selection of compatible mods available.

Edited February 24, 2020 by HvP

[strider3]

@HvP "Very frustrated" might be mild? . Although I agree with your belief that it might be time to ditch 1.7.3, I have one more screenshot which I would like to present. This is my latest attempt...the stock Senior docking port has force reduced to 40%, I have managed to approach to within 200 meters and target the station's docking port I wish to dock to without it coming apart. As I come within 20 meters of the target port, I turn off RCS and SAS on the arriving ship (note that SAS remains "on" on the station). As I dock, I get a small, quick "shudder" (nothing like the increasing "wobbles") and one part separates. It might be important to note that the one part is an octo-girder with internal fuel/LoX tanks (which I believe is "stock"?). What is interesting is that this girder was attached to the girder it separated from in the VAB...not in orbit. Reviewing older screenshots, this appears to be where the separations always occur? I am going to try this one more time, making sure the station's SAS is off before docking.

 

[strider3]

Successfully docked the same set of tanks, as above, after making sure the station's SAS was also off. I'm certainly not claiming any kind of victory here...but it is a start. I'm going to keep adding tanks to the station to see how it goes. I would like to have a working station before upgrading to a more recent version of KSP. Honestly, there are times I wish KSP would just give the updates a rest...and give us and the modders time to get caught up? I always seem to be a version or 2 behind, waiting for the mods I use to catch up .

[HvP]

3 hours ago, strider3 said:

It might be important to note that the one part is an octo-girder with internal fuel/LoX tanks (which I believe is "stock"?). What is interesting is that this girder was attached to the girder it separated from in the VAB...not in orbit.

Those octo-girders with the fuel in them are not stock. They are from the Near Future Construction mod pack.

You might want to check and see which version of Near Future Construction you are using. Look in the directory for the folder "GameData\NearFutureConstruction\Versioning" for a file called "NearFutureConstruction.version" and open it with any text editor like Notepad. There will be a change log that lists the version number for the mod as well as the version of KSP it was intended to be used with.

Also, when this happens are you seeing any errors in the console log? The next time it happens press ALT+F12 and go to the "Console" category at the top to see the debug info for your log file. Are there any yellow or red lines which mention any obvious mods or errors?

[strider3]

And...unsuccessfully docked the next set.... This time, it separated an already attached tank set from the tank set's docking port (not the station's port) at the 200 meter mark. The octo-girders are 1.7.3 KSP compatible. I will retry the docking and look for any errors. There seems to be no rhyme or reason to this, whatsoever...at 2,000 meters, at 200 meters, at targeting, at docking, at this joint, or, at that joint. I can repeat the last approach and it doesn't happen at 200 meters...but comes apart on targeting or docking. I just repeated the last docking attempt and...no problem at 200 meters??? Let us see if it does it on targeting or docking. I will make sure to look at the errors. Is there a way to see these errors in a simpler text type file?

And, voila! The exact same docking, performed a 3rd time from a save...and no issues. I understand that you want me to look for a "smoking gun"...I don't think there is one...not mods, not auto-struts, not SAS or RCS...I no longer believe there is any one thing wrong...other than my install of KSP 1.7.3.

So, let us end this thread. I definitely want to say "thank you!" to all who have replied and tried to help. I will, perhaps, try another, newer version...if my required mods are available...or I may just go shoot people on my XBox for a bit (it ALWAYS works...I like things that always work).

Edited February 27, 2020 by strider3

[strider3]

OK...I lied...let's keep this thread going because I have more..."observations". The following are helping me build my station:

1. Port Docking Acquire Force: I have found that setting this low (25%), on the arriving port has helped.

2. SAS and RCS: All "off" both on the station and the arriving ship, just before docking.

3. As my station gains "mass" (by successfully adding tank sets), all the issues at 2K meters, 200m, port targeting and port docking...all seem to go away? Maybe someone more knowledgeable can speak to this but, it seems that the "lighter" my station is (the less actual mass it has), the more susceptible it is to weirdness when crossing the 2km, 200m, targeting and docking thresholds? Not sure if that makes any sense...but it is working that way in practice.

I am 2 tanks short of having one entire side "built" . I will, hopefully, be able to post a screenie of the entire thing, ready for planetary exploration support, in the next week or so.

[strider3]

Nope, never mind...I lied again. All the suppositions I posted earlier are BS. The station continues to come apart whenever it wants to...no "smoking gun". It just...does it...when it wants to. It doesn't seem to matter at what point I'm into docking...it just comes apart whenever it wants to. I will now kill 4 months of work, delete a bunch of mods...and try again. I think from this point on, Parts Mods are "no Buenos". KIS, KAS and all the other parts mods can KMA. I will never again spend months trying to accomplish something that should have been done in days.

Niner out.