asas vs basic sas?

[deepspacecreeper]

hello, when should i use adv. sas or basic sas?

what should i use on space stations?

[capi3101]

The distinction between the two (SAS and ASAS) went away in 0.21; right now there is no functional difference between the two. That will change in later versions, no doubt.

[DMagic]

Go here if you want more info about the SAS system.

http://forum.kerbalspaceprogram.com/threads/41941-New-SAS-functionality-and-You%21-0-22-Update

[RocketPilot573]

There used to be a difference between the ASAS, SAS, and avionics package. Now it's all the same thing.

[Febin]

The ASAS is an obsolete part, it only existed to not break saves. Back in versions before .21, ASAS was the standard control part, when reaction wheels were reworked in .21, it was kept to not glitch ships from pre-.21.

[Frederf]

Avionics package is still different I believe. They are different Ki Kp Kd values than the default SAS program.

[RocketPilot573]

Avionics package is still different I believe. They are different Ki Kp Kd values than the default SAS program.

Umm, actually it's a science part now. It is no longer an SAS at all.

[Frederf]

I'm thinking a version or two ago then.

[deepspacecreeper]

so how does sas work?

compared to asas and bsas

[Gnipu]

It's the same, like they already said

[celem]

Asas is preferable in general right now since its the lightest sas-capable torque module in stock. However since its only available in large diameter I tend to use inline wheels at the top of payloads and asas in the tail of launchers. While dropping the light version and carrying the slightly heavier version with you makes little economic sense, it looks plain better if the top of your rocket is 1.25m diameter.

While not related to the original question but based on my comment about asas in launcher tail, be wary of putting asas directly above the mainstage engine between it and it's tank. It gives you wonderful ascent control, but it's relatively low impact tolerance can lead to some catastrophic first stages on the pad, mainsails above about 60% thrust at sealevel seem to have a tendancy to crumple mine.

Edited November 7, 2013 by celem

[capi3101]

Here - this may be helpful. It's out of date, but there at least information on what the distinction used to be.

In RL, a Reaction Wheel is essentially just a gyroscope. When the craft needs to turn, electric motors change the orientation of one of the three axes on which it is spinning; the effect of precession then works on the entire spacecraft as an "equal and opposite" reaction (i.e. Newton's Third Law). The end result is that the gyroscope returns to its original equilibrium, while the spacecraft's orientation has changed.

To experience the effect of precession yourself, take a bicycle wheel and grab it by any handhold you can place along its spinning axis. Hold it so that it is upright - parallel with your body (I suppose perpendicular would work too but parallel's easier on your body). Get somebody else to get that wheel spinning - get it going as fast as possible. Once the wheel's spinning, try to turn it; you'll experience a definite counter-force that will try to turn the wheel back to its original position. You can hold it in the new position, but it takes constant force. That's precession, it's how a gyroscope works, and in turn it's what a Reaction Wheel in KSP is based upon.

Asas is preferable in general right now since its the lightest sas-capable torque module in stock.

You mean the Large ASAS module, right? Both the Inline Reaction Wheel and Inline Advanced Stabilizer (i.e. the old SAS and ASAS modules) have the same mass - and yes, the Large ASAS module is less massive for some odd reason. All three work the same way nowadays, and with the inclusion of SAS capabilities with the command pods, all three are legacy parts - largely redundant.

Edited November 7, 2013 by capi3101

[DMagic]

so how does sas work?

compared to asas and bsas

Did you go to the tutorial I linked to? It's in my signature too. I think it explains most of what you need to know, but I'm not going to repost the whole thing here.

[Xiphos]

The answer is simple. Pre version .21, sas was a rotational lock(kill rotation) and asas was a heading hold. But like others have said, the parts were kept so as to not break saves.