Solved- centre of mass asteroid issue

[Vectura]

Asteroid capture is nearly impossible because of this. Having SAS on, several RCS thrusters on, at once, does not seem to be enough to stop my ship rotating when trying to maneuver with an asteroid. I am trying to do the asteroid redirect mission tutorial part 2 (I skipped part 1 because because I simply couldn't get an intercept)

Edited August 30, 2014 by Vectura

[sal_vager]

You can right click the claw and unlock it, allowing you to move your craft while still attached, this lets you align yourself with the CoM

[Vectura]

But how do I tell where the centre of mass is???

[magnemoe]

click on it and you get the option to set target to center of mass, you will never hit correctly so you will need some way to correct like the new high power truster using standard fuel.

[Vectura]

I never knew about the target centre of mass thing! Thanks!

[Spatzimaus]

Easier way: add a flexible connection of some kind. I prefer a winch from KAS, although you can do it in stock with certain parts (the docking ports). This allows the asteroid to rotate itself until its CoM is aligned with your thrust vector, although you want to be as close to aligned as you can get beforehand. At that point it'll oscillate around the connection point, but you can get around this by putting an SAS anchor on the asteroid itself to dampen the motion over time. (That is, an unmanned vessel with SAS, solar panels, and a few claws to anchor.)

In 0.23, this was my main asteroid vessel:

The hooks on the front (left) were the original design, using SAS to stabilize, but the setup on the back (right) was what I added once I realized that the flexible connection was far better. There's a small command pod and RCS jets on the claw end of the winch, so that I can steer it to a good anchor point.

The downside of this method is that while it's ideal for a single acceleration, if you're going to be doing multiple thrusts (or decelerating) you have to disconnect and move to a new angle for each. Disconnecting can be a bit dangerous, too, since the winch might flail around a bit. But for the gross adjustment of getting an asteroid into a basic orbit, it's a great way to do things.

[cantab]

Yeah, you can get reasonably accurate by targeting CoM when you come in to claw. For general manouverability I like to dot a few control sections around the asteroid, each with their own claw, a couple of reaction wheels, and some RCS thrusters and tanks.

Also, if you have a cluster of main engines, try seeing which way the asteroid wants to turn, then reducing the thrust limiters on the engine(s) on the "outside" of that turn.