My SAS gave up! Bug or not?

[RocketPilot573]

I have been annoyed by this for quite a while (ever since .22 came out), the .22 SAS has proven to be rather weak. Here is a pic of a ship:

As you can see, it is perfectly symmetric, is NOT currently turning, and has plenty of power and reaction wheels. Yet for some reason, the SAS indicator says it's in that "I'm not doing anything" Mode (the little orange arrows). That means that even if it DOES start turning (even just a little bit), then the SAS will continue to not do anything, the pitch, roll, and yaw indicators don't move a pixel.

This happens with or without mods. Mods currently installed are Mechjeb and Chatterer. Mechjeb was only added a few hours ago, and was not even on that ship. This also happened before i got chatterer (really, what harm could that mod do?).

So, is there any reason why this is happening? Docking that ship was nearly impossible with no SAS... (I has to resort to the space station doing the docking:confused:)

[Taki117]

Near as I can tell the orange arrows mean that it is in "dampening" mode which leads me to believe that there is either user input, or your craft is generating enough torque that SAS can't compensate for it. As far as I know this is not a bug.

[RocketPilot573]

Near as I can tell the orange arrows mean that it is in "dampening" mode which leads me to believe that there is either user input, or your craft is generating enough torque that SAS can't compensate for it. As far as I know this is not a bug.

As I said, the craft was NOT turning at ALL... About user input, I was not touching the keyboard, no trim was set, and my joystick was unplugged.

[Taki117]

As I said, the craft was NOT turning at ALL... About user input, I was not touching the keyboard, no trim was set, and my joystick was unplugged.

It's possible that it is a bug then, you could try turing it off and back on. (either with T or F) and see if that helps, or try reverting the flight and trying again. I'm no expert.

[Orbiter]

Were you using the joystick before this flight? I recently left my ksp on while playing a flight simulator with my joystick, and when I came back to ksp an unplugged my joystick, it had the exact same problem. I was able to fix it by plugging in the joystick and moving it around, then re-centering it, making sure to have all 3 indicators at neutral. I then unplugged it, and the problem went away. It could be that when you unplugged your joystick it goofed with the sas.

[Dispatcher]

I've noticed the same thing about SAS since the introduction of 0.22. It seems less consistent in behavior. I've seen some people refer to this as a feature and others as a bug. While I've learned to be more particular with SAS and reaction wheel placement, I'm never sure of the results until a test flight is done.

[DMagic]

Joysticks are notorious for doing this, even if they are unplugged. You can try uninstalling the driver, that sometimes fixes this.

The orange arrows indicated that SAS is in damping mode, which does provide some resistance to changes in heading, but its behavior is not really consistent, or it's at least hard to predict. Any input will briefly zero out all of the controls (which is why tapping the controls can cause an otherwise stable craft to start spinning out of control in some cases). Control should kick back in fairly quickly, but if the system is receiving some constant, random input from joystick drivers it will probably stay at zero-control indefinitely.

[Traches]

Yeah, if you have a joystick then check its calibration. That's done it to me before.

[nimbim]

It's a bug, but it is rather rare. Just go to the Space Center and back, no big deal.

[Roxette]

...you could try turning it off and back on...

Do you work in IT support by any chance?

[J.Random]

Do you work in IT support by any chance?

He isn't BOfH, that's for sure, or he would advise to do it three times.

[DrMonte]

Who is in charge of your ship? I mean from four docking ports and command capsule(s). I suppose there might be some issues with SAS if you will use side docking port in command.

[Roxette]

I'm surprised nobody yet has pointed out the visually obvious problem with controlling that ship - you have the equivalent of an orange tank and 6 senior docking ports at the front end, and the only RCS blocks are at the rear, so it will be extremely difficult to control, especially for docking, where precise lateral control is needed. It's hopelessly out of balance, which is probably contributing greatly to the SAS having to be constantly correcting, expecially with the multiple-engine thrust on the back.

[Taki117]

Do you work in IT support by any chance?

yep. It's amazing how often that fixes the issue.

[DMagic]

I'm surprised nobody yet has pointed out the visually obvious problem with controlling that ship - you have the equivalent of an orange tank and 6 senior docking ports at the front end, and the only RCS blocks are at the rear, so it will be extremely difficult to control, especially for docking, where precise lateral control is needed. It's hopelessly out of balance, which is probably contributing greatly to the SAS having to be constantly correcting, expecially with the multiple-engine thrust on the back.

It's hard to tell for sure, but I think I see two double rings of RCS thrusters, one at the back and one towards the middle. This won't be ideal for translation, but assuming you can get SAS working properly it should be doable. Using fine control mode (with CAPS lock) should almost completely alleviate any issues.

[Roxette]

But good translation control is precisely what you need to make docking comfortable, and not a real PITA. I find this tool http://kerbalspaceprogram.com/rcs-build-aid-v0-2/ invaluable in building craft that are under good control for docking.

[Deadweasel]

Nobody's asking the really obvious question: Has this ship EVER maneuvered the way you want it to?

Might help to place a ring of linear thrusters at each end as well. They don't add much drain to the fuel supply, and offer some fine tuning control to the whole thing.

I recently tried using a joystick and ran into the "ASAS stuck in manuever mode" as well, though my ship was constantly moving in one direction. It didn't go away until I'd removed the axis mappings in the settings.

In your case, try flying a different smaller design. Does the problem persist but with actual movement? Do you have a joystick mapped in your settings?

Otherwise, if this is the only ship it happens with, and has always done so, then it's probably a problem with the design, or possibly even a bug in its definition (.craft file) causing an awkward imbalance. Obviously you got it up to orbit, but what is its state once it's up there? If it's badly imbalanced it could be experiencing torsional forces so close to Kerbin's atmosphere.

-Just some thoughts to help find a solution.

[Roxette]

The other salient point about that ship - where is the probe core that's controlling it, and how is it oriented? From the visible data on the screen (810 units of electrical charge = the 8 battery packs visible/implied by symnetry + 10 : 10 units has to be one of the small probe cores, presumably mounted out of shot on the far side?

[Deadweasel]

The other salient point about that ship - where is the probe core that's controlling it, and how is it oriented? From the visible data on the screen (810 units of electrical charge = the 8 battery packs visible/implied by symnetry + 10 : 10 units has to be one of the small probe cores, presumably mounted out of shot on the far side?

That's a good point too! I'm also not seeing any of these reaction wheels previously mentioned (unless I'm just being blind...)

If there's only a small probe core on there, no wonder it's unable to move when the engines aren't firing (which will aid maneuvering via their gimbal action). Also, the orange "rotation" symbol on the SAS indicator isn't just indicating dampening mode; it can also indicate "maneuvering" mode. The ASAS is only attempting to cancel rotation when the player lets go of the orientation controls (ADWS), but the indicator will show that orange symbol for both.

Either way, if you're not touching the controls and ASAS is still solidly in that mode, it indicates that it simply can't effectively move the ship as it thinks is needed. Some kind of imbalance can cause the ship to want to move, even in vacuum. I have seen it happen on something that seems otherwise perfectly symmetrical, and yet it wants to rotate if I turn off the ASAS. If my maneuvering rig weren't powerful enough to compensate, I'd be seeing the same lack of control and constant damping action that you are.

[oobayly]

This is definitely a bug - I've encountered it numerous times in v.23 - I have a ship that's perfectly controllable, and then at some stage (normally after setting up a particularly precise manoeuvre node ) I'll find that the ship is completely uncontrollable. WASD [very slowly] moves the controls, and like the the OP they don't centre. Turning on SAS will cause the craft to start tumbling. Switching to another craft or going to the space centre and back again will reset the controls, but of course you've then lost your manouevre node, which is very frustrating.

[Deadweasel]

I've found this happens most often if you're warping when you hit the transition from one sphere of influence to another. I don't know if there's a particular warp "speed" that's considered safe, but I do know that every time I have been left unable to control my ship, it's almost always just after I've switched SoI while warping.

[Kryxal]

This is definitely a bug - I've encountered it numerous times in v.23 - I have a ship that's perfectly controllable, and then at some stage (normally after setting up a particularly precise manoeuvre node ) I'll find that the ship is completely uncontrollable. WASD [very slowly] moves the controls, and like the the OP they don't centre. Turning on SAS will cause the craft to start tumbling. Switching to another craft or going to the space centre and back again will reset the controls, but of course you've then lost your manouevre node, which is very frustrating.

There's actually an easy fix for that if you don't mind a mod (information-only, no parts): Kerbal Alarm Clock sets alarms on maneuver nodes and allows you to restore them.

[Starwhip]

List of tried and true mantras of our robotics team that often apply to KSP:

"Did you try turning it off and back on again?"

"If it ain't broke, DON'T fix it."

"Did you change something recently?"

"Try to wiggle it a little bit."

Try those and see how it works

[RocketPilot573]

Hey look, my thread is back from the dead!

Um, this has kinda improved in .23, spacecraft and rockets are fine, but planes, especially SSTOs, are still hard to fly. Also, there are still numerous phantom rotation bugs, and the SAS no longer holds other axis when turning the ship on one axis (it did that in .21).

But whatever, these things will probably take many updates to be resolved...

[DocMoriarty]

IMO this is a bug. I've noticed in 0.23 several times ships that were completely stable in orbit with SAS engaged suddenly start turning a bit until i catch them again.