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Did the way SAS works change?


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So now that I've started playing again, I've noticed that stock SAS doesn't seem to be as strong as it used to be (as evident by a near disaster Mun mission). Is this because my pilot is still level 1 or is it because SAS was nerfed?

On a related note, did they implement some sort of fix for the whole "warp to stop ship rotation" thing? Seems like even though my ship stops rotating when I warp, soon as I come back out it starts rotating again on its own.

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SAS in 1.0.x seems to overcompensate when it has access to strong gimbal authority. There is also weirdness with some engines giving instant gimbal response, further exaggerating the issue.

I personally do not believe this to be intended and would log it as a bug.

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SAS in 1.0.x seems to overcompensate when it has access to strong gimbal authority.

Or to undercompensate on slightly imbalanced ships. Current SAS-system always had a bunch of issues and isn't too reliable.

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SAS has been totally re-designed over the course of the last few patches. While they did move it to the Kerbal instead of the part, leveling your Kerbal only grants you automatic repositioning (you can have him hold prograde, retrograde, normal, anit-normal, radial, anti-radial, and even at high levels right at your maneuver), it doesn't grant you more torque. Torque was also reduced on the command modules in order to keep the SAS modules still useful. So if you have a larger craft, you may need to add an SAS module for that extra turning ability.

Torque and SAS were completely eliminated from many of the probes, which my belief is that they intended the change to include more diversity amongst them. However, my experience has been to pretend like those probe cores don't exist so it has effectively done the opposite and all I ever use in the early tech tree is the OKTO. I've even gone as far as to simply delete the OKTO2, QBE, and Stayputnik so I can fit more mod parts and stop getting contracts that I will never do, without at least a reaction wheel that is just how useless they are in my opinion.

Edited by Alshain
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Even without SAS the early cores are at least a little useful - I've successfully used the Stayputnik to get some altitude records, especially with slightly canted fins to put some spin on my rockets.

I only tried one Mun landing with it, though - and that wasn't successful.

Well if you have alternate means of turning (RCS, Fins, Gimbal, or Reaction Wheel module) then it can work but that doesn't make them worthwhile or all that useful when you have the OKTO. But there is a difference between SAS and Reaction Wheel/Torque. You can't re-orient a Stayputnik satellite in space by itself without one of the above items, you can't even point it at prograde to circularize. With the OKTO you can. So why would you ever use the Stayputnik?

Anyway, a bit off topic, but I think the OP intended to include Reaction Wheels AND SAS in the conversation. A lot of people confuse the two. I could be mistaken, but based on his description of a near Mun disaster, it sounds like he was fighting the craft to reorient itself.

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I hate 2 changes they made to SAS.

#1) That the SAS will automatically reset the heading that it tried to hold when a force acts upon it... this is really really really really annoying for flying in the atmosphere.

#2) That version of SAS in .18 (when you didn't have an ASAS module) is no where to be found... Oh how I miss that mode of it just stopping rotation, but doing nothing else.

Its really annoying that as I try to do small control inputs, the SAS simply counteracts them as soon as I release the key.... yet if I hold the key down a little longer, it will reset the heading that it tries to hold.

I've also noticed that the normal SAS hold seems to smoothly apply forces... and to slow down the rotation as it approaches the desired heading.

However, the prograde/radial/normal holds will apply full force when not pointed in the right direction, and will hold that force basically continuously... not slowing the rotation down as it nears the correct heading... resulting in large oscillations around the desired heading, that you have to manually dampen

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Well, for that to apply we first need it to actually be a PID controller. Currently it isn't - as can be evidenced by the fact that it'll drift and stay that way.

Said drifting making the standard "hold orientation" almost useless almost always, unfortunately. For instance, with spaceplane reentries you can't simply hold 45 degrees any more - over time it'll slip down to less angle of attack and stay there even though it has the torque to make it most of the way there if not all.

It also holds an absolute alignment as opposed to body-relative, which means you have to make constant corrections anyways with spaceplanes.

I personally wish it was something along the lines of "hold angle X relative to Y". So if you control-clicked or something on one of the icons it'd change to hold the current orientation relative to the selected mode. Ten degrees off of prograde in a specific direction, for instance.

Or at the very least, I wish there was a way to *actually* lock in a direction to hold. I currently resort to making maneuver nodes with absurd amounts of dv and telling it to hold to the maneuver node, which works better - which says a lot in and of itself.

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I really dont know but i depends also where exactly you install your Reaction Wheel Modules...

To me it seems like putting them precise in CoM, or when two of them in same distance to it gives a significant advantage.

Putting them aside the main Root of the craft in pairs and opposite to each other is for me obviously a very bad idea.

I tried alot of things, planes are prone to bad Reaction Wheel placement, Launchers not so much i think.

Carreer Pilots with 3-4 stars and more are for me the best solution. Very accurate manouvering, no overshooting, no unnecessary rotating.

I sometimes have an Issue with lateral drift to the Right in Level Flight in Athmosphere, switching off and on again solves the Thing allways.

Edited by Mikki
Reaction Wheel instead SAS, uups
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Or at the very least, I wish there was a way to *actually* lock in a direction to hold. I currently resort to making maneuver nodes with absurd amounts of dv and telling it to hold to the maneuver node, which works better - which says a lot in and of itself.

Interesting idea... that inability to lock in the direction it hold angers me to no end... this may be a clunky workaround until squad fixes it (which may be forever)

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Well, for that to apply we first need it to actually be a PID controller. Currently it isn't - as can be evidenced by the fact that it'll drift and stay that way.

Said drifting making the standard "hold orientation" almost useless almost always, unfortunately. For instance, with spaceplane reentries you can't simply hold 45 degrees any more - over time it'll slip down to less angle of attack and stay there even though it has the torque to make it most of the way there if not all.

That's actually something else entirely, the orientation you lock to is not surface relative causing you to "pitch up" as you travel around the planet. With a vessel coming in at orbital speeds the effect is very noticeable. The direction it holds is constant, it's just not constant relative to ground normal.

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That's actually something else entirely, the orientation you lock to is not surface relative causing you to "pitch up" as you travel around the planet. With a vessel coming in at orbital speeds the effect is very noticeable. The direction it holds is constant, it's just not constant relative to ground normal.

No, in that case angle of attack would be increasing, not decreasing. Sometimes, if you don't have overwhelming torque, or possibly it's an issue of wing placement, the nose will drift downwards over time, until the plane is in a full dive and getting far more lift toward the front. This sometimes happened in the old aero model (I haven't got around to planes in new aero yet, but it seems to be what is being described).

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Oh, the "I give up and will just slide" mode. That I can agree is a right PITA, but it does have a purpose (not breaking vessels in two).

Except that a) it doesn't even work for that, and B) I'm talking about spaceplanes which have no problems with not breaking apart under manual control.

A better option would be to have reaction wheel (and RCS) control strength tweakable, and always have SAS actually try to point in the right direction.

And ideally, have top-level pilots automatically prioritize reactions wheels over RCS when possible. But that is another topic.

- - - Updated - - -

It seems to have to do with how much external forcing there is. On a direction with little-to-no control input required once things settle down, it's perfectly fine. On a direction where there's systematic control input required? It's utterly useless. (For instance: reentry with a spaceplane. It's absolute direction as opposed to relative to the body you're orbiting, yes - but the horizon doesn't change 45 degrees in 5 seconds)

And trim doesn't even work with SAS.

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That the SAS will automatically reset the heading that it tried to hold when a force acts upon it... this is really really really really annoying for flying in the atmosphere.

Yeah, the old SAS was better. It was also great for landing landers because it would hold direction and you could slightly tilt your craft to correct lateral speed and have it return back.

Thankfully MJ can do all of this.

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Yeah, the old SAS was better. It was also great for landing landers because it would hold direction and you could slightly tilt your craft to correct lateral speed and have it return back.

Thankfully MJ can do all of this.

yes, mechjeb also use an fraction of the electricity holding prograde or retrograde, an ship with an MK1 pod and 3-400 electricity tended to run dry if you use it aerobrake from Mun or minmus in shadow or or solar panels retracted.

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