Spacecraft control, how does it work?

[Iansson]

I´m a complete newbie to this and I´m curious about something i just couldn´t find while searching the forum...

Could someone give me an explanaition about how the spacecraft controls work in KSP?

What makes me courious is that when you go carrer mode you start with no engines with thrust vectoring capability and no winglets with control surfaces, but you´re still able to steer the spaceraft. The reaction wheels on the command pod only measures the tourqe of the controls, not the control itself, rigth?

So what makes you control those first rockets? The black magic of unwritten code?

[sal_vager]

The pods actually have reaction wheels of their own, though they aren't very powerful they are enough for most early designs.

The pods have batteries and will draw on that power to rotate, while most engines recharge them, if you run out of power you'll find your ability to turn will be gone.

50 electric charge is enough to do most of what you might want to do in orbit though, and is enough to get to the Mun or Minmus and back if you're careful

[RocketPilot573]

I don't understand what you mean... You said it yourself that the pods have build it reaction wheels.

EDIT: Ninja'd...

[peadar1987]

Reaction wheels are weighted discs spinning really fast, so if you try and change the speed of their rotation, the reaction will twist the rocket in the other direction. For a small rocket, this is enough to change its heading pretty considerably. Bigger rockets need RCS to get any sort of meaningful control for a reasonable amount of mass.

[CaptainArchmage]

All command pods have reaction wheels built in, and that controls the craft including at the very start of career mode. Winglets use aerodynamic forces, so you have to be moving at some speed before they start to become effective, and be in an atmosphere. RCS uses thrusters.

Reaction wheels require electric power, but as pointed out by sal_vager, you have 50 units of electric charge stored on the command pods. The LV-T30 engines also produce electric charge as they are running. If you need more charge, you can stack another pod on your craft, turn off the reaction wheels, and maybe leave it empty, giving you an extra 50 units. It is possible to do a Mün mission just using the 50 units of electric charge, if your spacecraft can get there.

Edited December 9, 2013 by CaptainArchmage

[bsalis]

To add to this.

Reaction wheels have no friction and do not saturate in the game.

Reaction wheel force is additive when you have multiple parts that have them.

[Soda Popinski]

To add further, in real life, they're often called gyroscopes. Which is confusing, since different types of gyroscopes are used to detect orientational changes. These are what failed on the Keppler Space Telescope.

[mythbusters844]

To add further, in real life, they're often called gyroscopes. Which is confusing, since different types of gyroscopes are used to detect orientational changes. These are what failed on the Keppler Space Telescope.

Actually, they aren't. Gyroscopes are something completely different.

EDIT: Misread... but they are supposed to be called reaction wheels

http://en.wikipedia.org/wiki/Reaction_wheel