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Holy sciencey title Batman! Basically what I'm suggesting is for SAS to be a module on command pods/probe cores that's automatically assigned to the SAS action group but can be removed and set on other action groups, just like the brakes on wheels and lights in lights and crew parts. What this would do is open up an entirely new action group with new properties. I know you can already set things to the SAS action group, but it's basically suicide to disable SAS mid-flight, especially in some aircraft. As for the "new properties" I mentioned a sentence or two ago, the SAS action group can be on or off, and can have the state temporarily reversed by holding the F key. This would be useful for things such as Space X-style booster landings or SSTO re-entries where briefly deploying all your airbrakes or retracting them to keep them from blowing up from the re-entry heat or to fine-tune your trajectory would be extremely useful. TL;DR - Make SAS an action group like brakes or lights to free it up for other things where temporarily inverting the state of a part would be required/useful.

Hello ! I've recently put a few satellite into orbit with 2 robot control units : The 1st one is supposed to be facing Normal and the 2nd one Radial In. But I'm encountering a problem : Once SAS activated I choose "Control From Here" for the 1st one and choose "Normal" after that I switch to the second control unit and it immediately turn up to Normal... My question is : Is there a way to choose 2 different orientations for the control units on the same craft ?

So lately I have taken to the habit of building many of my rovers with reaction wheels, and I set all the electric torque components to "SAS Only" mode. I find that this helps a lot on flat(ish) terrain, making the rover less likely to flip over when aggressively breaking or making sharp turns, as the torque of the reaction wheels in SAS mode helps cancel out forces that might send the rover spinning. But experience has taught me that on rougher terrain where gravity is lower and changes in elevation more sharp than on much of Kerbin (like, say, the Mun) I have to "pulse" deactivation of the SAS at times to make sure all the wheels return to the ground. If I end up taking a big leap off the terrain, the reaction wheels can be used to help make sure it lands at a good angle, but I have to manually change their mode, which is not easy to do under pressure during an unexpected leap. Basically I want to control the torque fully if the vehicle is off the ground, while keeping the vehicle firmly planted on the surface while grounded. So, to resolve this and make rovers a little more controllable, I would like a "parallel to surface" mode for the SAS, which tries to keep the vehicle's "front" (as defined by whatever I select "control from here" from) perpendicular to a normal vector from whatever surface polygon lies directly below it. I would think that this would be pretty simple, as far as engine capability and math goes. Do a ray trace from the center of mass of the vehicle to the center of the stellar object it is in the sphere of influence of, then get the normal vector of the first non-vessel collision polygon it passes through (which would typically be part of a planet's terrain mesh.) Then we try to have the SAS keep the vessel's forward pointing vector perpendicular to that surface normal vector. The advantage to this is that the vehicle will try to keep itself oriented properly so we do not have it doing bizarre things like trying to maintain a wheely, which reduces driver control. It also means that, should the vehicle launch itself into a parabola, it would try to align itself with whatever it is passing over so it lands on its bottom as evenly as possible. This should help spread out the impact of landing and lead to less damage over all. Heck, if we want to introduce a simpler version of the same thing which can just keep a craft pointed perpendicular to a vector traced down to a stellar object's center, that would also help as a great aid for flying aircraft while cruising long distances instead of having a make a bunch of minor corrections for the pitch of the nose. If there is some concern about this making things "too easy" on the players, it could be restricted to higher level probe cores and experienced pilots, like many of the other "autopilot" features in the base game. It would also build up player experience in cruder situations in career or science before they unlock the more helpful assist gear. Heck, I would even go with some add-on components like gyroscopes to enable it (similar to the Avionics Hub) if there needs to be some kind of (mass/cost) trade-off for that ability. What do you think?

I'm having a frustrating problem. I have a lander in orbit around the Moon (this is with RSS). I cannot control the orbiter's direction, for some reason. I hit the normal keys to rotate, and it just won't move. I have MechJeb on it, and if I use Smart A.S.S. to orient to prograde, retrograde, whatever, that works, but other than that, the keys that orient the spacecraft don't work. It worked fine through several reloads, trying different landing approaches, but now it just... doesn't work any more. I have two different saves for this vehicle at various stages. If I load either of them, the problem is the same. If I switch to another craft in orbit, everything works normally. I've checked that I have battery power, and the reaction wheels are turned on. But no manual control is possible of this craft. I have also tried restarting KSP. My mods include RSS, MechJeb, Kerbal Engineer, and FASA. Ugh, I figured it out. Now I feel stupid. The satellite I was using to bounce my signal back to Earth is on the other side of the moon, and I'm on the far side. So no control. Oof.

I am working on a plugin for docking and am trying to align the current vessel with the docking axis of the target. I am trying to use the vessel Autopilot.SAS to do this and so far it does not seem to work. In my FixedUpdate() handler I am first ensuring that it is in StabilityAssist mode: if (vessel.Autopilot.Mode != VesselAutopilot.AutopilotMode.StabilityAssist) { Deb.Log("Engaging StabilityAssist"); vessel.Autopilot.SetMode(VesselAutopilot.AutopilotMode.StabilityAssist); sas_orientation_set = false; } And then calculating a quaternion based on the target zaxis (which is the target transform forward vector) and the target transform up vector: Quaternion quat = Quaternion.LookRotation(-zaxis, tgt_tr.up.normalized); And then setting that if I have not already set it: if (!sas_orientation_set) { Deb.Log("SAS set to quat: {0}", quat); vessel.Autopilot.SAS.LockRotation(quat); sas_orientation_set = true; } I also am printing out the current "lockedRotation" quant and what I set it to: Deb.Log("currentRotationLock: {0}", vessel.Autopilot.SAS.lockedRotation); Deb.Log("desiredRotationLock: {0}", quat); Initially the two values match up, but after a few updates, the lockedRotation value changes to what it was before I set it: [LOG 23:42:22.139] [KRAMAX] currentRotationLock: (0.0, -0.6, 0.0, -0.8) [LOG 23:42:22.139] [KRAMAX] desiredRotationLock: (-0.3, -0.3, 0.2, 0.9) [LOG 23:42:22.140] [KRAMAX] SAS set to quat: (-0.3, -0.3, 0.2, 0.9) [LOG 23:42:22.163] [KRAMAX] currentRotationLock: (-0.3, -0.3, 0.2, 0.9) [LOG 23:42:22.164] [KRAMAX] desiredRotationLock: (-0.3, -0.3, 0.2, 0.9) [LOG 23:42:22.164] [KRAMAX] SAS set to quat: (-0.3, -0.3, 0.2, 0.9) [LOG 23:42:22.187] [KRAMAX] currentRotationLock: (-0.3, -0.3, 0.2, 0.9) [LOG 23:42:22.187] [KRAMAX] desiredRotationLock: (-0.3, -0.3, 0.2, 0.9) [LOG 23:42:22.192] [KRAMAX] currentRotationLock: (0.0, -0.6, 0.0, -0.8) [LOG 23:42:22.193] [KRAMAX] desiredRotationLock: (-0.3, -0.3, 0.2, 0.9) [LOG 23:42:22.215] [KRAMAX] currentRotationLock: (0.0, -0.6, 0.0, -0.8) Does anyone know how to make this work? I would really like to use SAS to do this and not have to write my own yaw/pitch/roll autopilot or require users to use mechjeb. -Thanks, Kramer

S.A.S. Issues... Everubody knows that in versions 1.3.0 and downwards there is a major glitch, one that everybody dreads... the famous S.A.S. Wobble glitch that occurs when you have too tall of a rocket. I was just wondering has this been fixed (because I have not played on K.S.P. 1.3.1 due to a broken computer, you can see my other post if you have knolage about building pc’s)? And if it has not been fixed, how do you get around the glitch, I found that if you put something to control your rocket closest to the engines than it will fix the glitch, but that is expensive, inconvenient, and it makes K.S.P. Rocketry harder than it needs to be. So: P.C. Question form/post Is there a way to fix the S.A.S. wobble glitch that occurs for tall rockets without adding a control point near the engines?

I am having an issue where ships that are not currently the active vessel are not maintaining heading with SAS. https://imgur.com/a/pZWRu The ship that has my Kerbal is in atmo on Kerbin and detaches a probe. I switch focus to this probe, set SAS and set heading to be retrograde. This works great and the probe maintains a retrograde direction as it decends. I switch focus back to the other ship and watch as the probe descends and I can see it start to tumble. I switch back to the probe and it has indeed started tumbling around, but now that it is the active vessel it regains a retrograde heading and maintains it as long as it is the active vessel. At any time if I switch back to the other ship the heading is again lost. Is this a stock bug? I have several mods installed but nothing that I think could mess up heading and SAS controls. Has anyone else seen this?

I would greatly appreciate an SAS mode that holds the navball orientation at the horizon, perhaps locking all remaining degrees of freedom (like roll and rotation along the horizon). This would allow aircraft to fly long distances across the planet without player intervention, which would be especially useful for long flights to contract related sites, e.g. on Kerbin. I do think it is reasonably simplistic to warrant being an SAS feature.

Hi, I've got a vessel stuck in low Kerbin orbit which desperately needs a Level 1 or better pilot to re-enter safely. The re-entry module was badly designed and it wants to tip over the wrong way (heat shield up, Mk1 command pod down) in the atmosphere; I've tried (many times) and failed to re-enter it manually without hitting the ground too hard. However, when I fly the same craft with Jebediah Kerman (who's currently at Level 1) on board, he can keep it stable all the way down with the "hold retrograde" SAS option. :-) The stranded vessel has three tourists on board, so all it has is an OKTO probe's SAS, which doesn't support "hold retrograde". The usual rescue options are precluded because 1) it doesn't have a docking port, 2) tourists can't EVA, and 3) there are no empty seats for me to EVA a pilot into. So I had an idea "what if I could use Remote Pilot Assist to transfer a Level 1 pilot's skills to it". I'm having some trouble getting this to work, though. As a preliminary test, I built a simple craft which has a Mk1-2 (3 man) command pod, two HG-5 (relay) antennas, a stack of batteries on top, and a token engine (not enough to get it off the ground) so that I can "launch" the thing and get the MET clock going without actually moving it anywhere. I then attempted to use it to control an unmanned probe (OKTO-based) which I already have up in keosynchronous orbit with visibility of the launch pad. However, it's not working. Even with two level 1 pilots on board the ground craft, both craft's antennas extended (they are both equipped with HG-5's), the orbiting probe still has only the OKTO's basic SAS (stability assist only) and the status bar at the top of the screen indicates it's being controlled from KSC, not the remote craft. In map view on the ground control pod, when I set it to "vessel links" it shows a faint green line from the ground control pod to the orbiting probe, so they do have a line-of-sight link. But still...the piloting skills are not being transferred. Am I missing something? Some requirement that's not met one one or other of the craft? Some button I need to press to activate the Remote Pilot Assist? Or does Remote Pilot Assist only kick in when the "normal" DSN link to KSC is occluded/too weak? Or does it not like the fact that the control craft is landed on Kerbin? (Should that even matter, since I did "launch" the thing and the mission clock is counting up like it should?) Thanks...any ideas are appreciated. :-)

Not sure if i am doing something wrong but when i do an EVA it is not acting the way it used to. When i do an EVA the kerbal just spins out of control even with the RCS switched on he is always slowly rotating, meaning constant corrections and usually over corrections. Turning on the SAS also has no stabilising effect to the Kerbal. I've noticed that the navball on the screen does not link to the Kerbal either. It seems to still just show the reading for the ship i just got out of. Spinning the Kerbal around does not move the navball at all. It did used to. This is all made worse by not having a camera angle that locks you to the kerbal. The camera is always pointing in one direction and he is just spining on the screen, making it incredibly difficult to use RCS to bring him to a halt because he is rotating on all three axis so it is very difficult to work out which way to thrust to get him to stabilise if you are currently looking at him from an odd angle, not directly at his back. I have installed some mods lately, previously using stock i do not remember having these issues. EVA's were always quite easy. Is anyone aware of a mod that has caused these issues previously? I'm using 1.2.2. It seems to be Navball related as both the direction heading and SAS found on the Navball are just not tying to the Kerbal. The only Navball mod i use is Draggable Navball. Any ideas appreciated. Daniel

Hey guys, quick question here. BTW, I tried my best to search for an answer, but couldn't seem to find one, so I apologize if it's been asked before. Are there hotkeys for the SAS hold buttons? I especially use the 'hold prograde' throughout a lot of the ascent of my rockets. I'm visually impaired, so it's been a thing where I have to pause the game to give me time to find and click the button, and it's kind of getting old. Might there be a mod that allows me to assign these SAS holds to action-groups? Thanks!

In my experience (1000+ hrs) SAS has always had a really difficult time negating steady-state error. As I understand it, SAS uses a PID controller to maintain a constant heading, and the wiki confirms this. However, the integral gain must be set to zero (a PD controller), because the system simply does not respond to steady-state error. You can see this yourself with any spacecraft where the thrust vector doesn't intersect the CoM. Setting the SAS and engaging the engines causes the craft to slew. The SAS will stop the slew after a few degrees (depending on the strength of your control schema), but it doesnt even try to get the heading back to the original state, even if the control axes are not pegged. It seems like the directional holds are slightly better at countering error but this may be blind optimism. If anyone has any insight into why this may be it would be greatly appreciated.

KSP 1.2.2.1622 This sporadic bug has been driving me crazy. It mostly seems to occur when launching spaceplanes - 15 to 20 minutes after takeoff, SAS silently stops making inputs to correct the flight path, right when you actually start to need it since you're getting out of the atmosphere. Quitting the game and reloading from a save seems to fix it. This image sequence shows what happens. We're set to prograde and the nose is down and to the right of Prograde, and moving further in that direction. However, SAS is not applying any control inputs to correct this As you can see we have electrical charge, reaction wheels are enabled and set normal, and i'm stabbing alt + x for all it's worth. SAS still does not feel the need to correct. As we pitch past 90 deg nose down, it abruptly wakes up. But not to pitch. Instead it gives a hard bootful of left rudder. As we swap ends, the nose goes past the radial out position. It starts feeding in opposite rudder to kill the yaw. Job done ! SAS appears happy with its work, and leaves our nose pointing this way. Not quite prograde is it though? What about my circularisation burn? In this example at least, it seems SAS stopped monitoring Pitch altogether. When we went past 90 degrees nose down, the yaw angle display would have reversed, so it tried to fix that - and nothing else. I have mods (stock visual enhancements), so i guess i have to post in this forum. Does any long time player really play this game 100% stock? I uninstalled mechjeb and kerbal engineer, in case they were causing it. Due to the sporadic nature of the fault, it looked as though it might help, only to recur a few hours later.

I did a search and couldn't find anything, but I was wondering if/when this one is getting addressed? It's about the most frustrating thing for me right now, I don't want to suffer from it in campaign so I just stay in the sandbox which makes me feel like I'm missing out on something. http://bugs.kerbalspaceprogram.com/issues/10212

SO I played the game last in 1.1 and sas was fine no problem worked as it should and kept my rockets flying straight. When after many months I come into 1.2 and decide to launch a rocket I turn on sas and launch. And the rocket has no sas on or so it seems. before sas kept the rocket stable stopped the spinning worked all round as expected. now it acts like nothing is happening, doesn't correct (or if it does it's not helping) wont stop spinning rolling or anything of the sorts and makes the rocket give the ground an unpleasant explosive kiss.

Anyone else noticed a hyperactive roll on their ships? It's like the SAS can't find a sweet spot or dead zone and goes too far and has to correct over and over. My kerbals have all made claims for sea sickness and sold all their rocking chairs.

Reaction wheels that are turned on use power when in timewarp, right? (e.g. when you have SAS set to "stabilize" or "follow target") After having them drain all my power a few times, I got in the habit a while back of always turning off SAS when I leave a ship (e.g. when I return to Space Center / Tracking Station). I'm wondering, is there a way to hibernate them similar to command modules? Could hibernate capability be added via CFG edits?

Somethin I would like to see would be an SAS mode where the SAS tries its hardest to stay pointed at the angle it was facing in when enabled. Even if the player provides input, on release the craft would try to re-orient back to its initial angle. To actually change the craft's angle you would need to change the SAS mode or switch off the SAS, which can easily be done quickly with the F button. I think this would be useful for those crafts where you want to stay pointing in one direction, but the SAS slowly creeps away and you have to keep correcting it, leading to a loss of efficiency.

I'm curious about this. I've tried doing some research and find lots of info about wobble in large builds, but that has to do with the various parts of the ship flexing. This is not related to that, as my craft is only a small handful of parts. So, I've built a small, two-stage, sub-orbital probe using Procedural Parts fuel tanks, with a pair of reaction wheels (one 1.25m on stage one, and one .625m on stage two with the probe core). Stage one is a Swivel engine, stage two is a Terrier. Stage one launches nicely, and it flies quite well. This is actually the first design I've made that I have successfully executed a gravity turn with. I have to play with the throttle all the way up, otherwise it will go unstable and start flipping at around 25,000m. The problem comes in stage 2. For some reason, the SAS causes the craft to wobble endlessly, and I don't know why. It's wasting my electric charge from all the constant control inputs. If I turn off the reaction wheel, the craft just floats wildly out of control because the probe core doesn't have a built-in reaction wheel. I've had this problem before, but it was usually associated with having multiple active reaction wheels or RCS thrusters that were interfering with each other. This time, I have only the one reaction wheel active. Any ideas?

The way stability assist seems to work at the moment is it holds your position based on some universal plane; while this is great for orbiting celestial bodies, it is a pain in the atmosphere. I suggest changing the plane of reference when surface mode is engaged to lock onto the current angle and orientation of the navball. If you wish to hold 20° vertically while travelling east, face east and aim at 20° then engage stability assist in surface mode. When the navball is changed to orbital mode then change the plane of reference back to its normal behavior (the way stability assist works now).

hi. today i wanted to go for dres and back. i think you know, that it is pretty easy to re-entry in kerbin's atmosphere with just SAS turned off. but stuff happens, and SAS kraken attacks. again... idk what to do, because my orbit speed is 5k m/s, and no fuel left. when i tried to aim retrograde, i always fail (because of ridiculous re-entry speed). does someone knows how to fix this?

If I set a docking port as target and turn SAS on target tracking, then go to orient the other craft to orient and come back the first one goes back to the default SAS mode. Can we have the SAS working on both and track each other so we just have to align 1 craft instead of going back and forth?

Hi, I've found a bug most likely caused by remotetech, after the recent 1.1.3 ksp update I found I couldn't launch an unmammed rocket. The main problems are "T" and the space bar don't work, these actions couldn't be clicked on either, has anyone come across anything like this? also I've deleted my add ons and isolated it to remotetech, any help would be greatly appreciated.

Hi All, Experiencing a strange bug where on some (not all) of my vessels, I suddenly cannot toggle SAS (i.e. I could yesterday). When I hit T it goes on for a fraction of a second, thats it. Doesn't change if I hold down the key. I'm using RemoteTech which I feel might be relevant here. Anyone experienced this before? http://imgur.com/8LAukQ6

Since the 1.1.xxx update/upgrade, any attempts I make to use SAS and target markers [retro, prograde, radial,...] the nav ball targets jitter, the craft wobbles erratically making those features totally unusable for me. I have to click a marker on the left of the nav ball, wait until it comes almost locked, then disengage SAS and re-engage it, make manual adjustments [WASD] to get aligned. HELP!??