RCS how does it work?

[RikTelner]

After reading -> http://wiki.kerbalspaceprogram.com/wiki/Reaction_Control_System

I am coming to answer that says that RCS and SAS are same, but RCS uses RCS fuel and the little thrusters, and SAS uses "keyboard" and wings.

But I am 100% sure, that its not correct since no one would like to have RCS on board if SAS would be free.

So, could someone explain me please, what happens if I activate RCS? With SAS, its just assistance with helping keeping rocket pointing to same point. And RCS?

Edited October 22, 2013 by RikTelner

[Guest Brody_Peffley]

Its to help move spacecraft in space.

[Awaras]

Both SAS and RCS can be used to rotate your ship, but only RCS can be used to translate the ship (move sideways).

[RikTelner]

@Awaras, can RCS be "told" which sideway to go (left, forward, back or on right), if yes, how?

[Kialar]

SAS uses torque to control roll, pitch, direction and so on.

You might use to do that with RCS, too, but in addition you may use RCS for (low level) acceleration and deceleration maneuvres. That's what it was invented for.

RCS means reaction control system, and though, you use it for fine tuning of your route of flight, e.g for docking and/or deceleration in low gravitiy landings.

With SAS/torque only, you will not be able to do a correction of your trajectories at all if all other engines are shut down.

In game, use "R" to activate your RCS, "H" for accelerating forward, "N" for accelerating backwards, "I", "J", "K", "L" for lateral movement, "WASD" for rotation (as torque only would do).

For proper use install mono propellant and control thrusters.

-Kia

[blizzy78]

SAS uses torque to control roll, pitch, direction and so on.

SAS uses whatever control authority it can get: torque, wings, RCS, engine gimbaling.

Edited October 22, 2013 by blizzy78

[RikTelner]

So... RCS is kinda thing, that if I am not coming onto (for example) Mun with 90 degrees, but for example 140 degrees, it will help me stabilize to 90 degrees, so I can land easier?

[Melcom]

The larger the craft, the heavier it is. SAS works with gyroscopes to create torque to spin a spacecraft. This is limited, so a heavy ship needs a tool to be controlled. RCS is much more precise and necessary to dock. Depending on how you place your RCS-thrusters, you can go also forward and backwards.

[blizzy78]

So... RCS is kinda thing, that if I am not coming onto (for example) Mun with 90 degrees, but for example 140 degrees, it will help me stabilize to 90 degrees, so I can land easier?

No. Even though RCS uses thrusters much like an engine is a thruster, the thrust is VERY low. You CAN use it to make large-scale orbital maneuvers like an inclination change, but it's not designed for that. RCS is most commonly used to perform docking maneuvers where small changes in velocity with high precision is desired.

[Kialar]

SAS uses whatever control authority it can get: torque, wings, RCS.

OK. You are right.

[RikTelner]

Thank you.