Unmanned Satellites out of Control

[postman_666]

Hello I am wondering if you could help me.

I am a beginner, but have successfully made it to orbit many times now (not to the mun yet) and I am trying to launch a satellite.

For some reason, using practically the design as my manned rocket, the unmanned one (w/ SAS) goes out of control so easily!

any tips?

[NASAHireMe]

Welcome to the forums! We look forward to your questions, and as you master KSP, your contributions to the community.

There are many, many different reasons why this may be occurring.

1. Just because you have SAS on a probe core does not mean that you have control authority. Without reaction wheels, RCS systems, or a thrusting, gimbaled engine, the probe core often doesn't have enough torque to control a vehicle on its own. Consider installing more reaction wheels or a gimbaled engine to gain more torque.

2. Where do you lose control? If you are losing control in the atmosphere, remember that drag will cause your rocket to flip if your rocket is not in-line with your prograde vector. If you're losing control out of the atmosphere, consider #1 above.

3. You may be running out of electricity, which causes your probe core to stop working and SAS to shut off. Install more solar panels or batteries.

There are many other possible problems, but there's a start.

[Coga19000]

More to the point, if you lose control because of electric charge deprivation, try using engines with alternators ; they produce electricity while firing. Of course, if Control is lost while coasting to apoapsis, this point is moot, and you have to simply add solar panels/more batteries.

If Control is lost while in the atmoshpere, it may be due to atmospheric drag; an octagonal 0.675m core sitting smack on top of a round -sided 1.25m tank is not the most streamlined design. Try hiding the core in a Service Bay (where you can also how some Batteries) , in the top of which you can slap a nose cone, and voila! Fairings are generally not worth it for simple sats. You might also consider adding steerable fins (av symmetry of three is the minimum amount). The control authority those buggers provide is tremendous, but rely upon then too must and you will be immobile where the air don't blow (in a vacuum)

So yeah, the dust Akron is to add a reaction wheel, but if you can avoid using, you will save the around 100kg it adds ;and the smaller the rocket is, the more changes to the payload matter.