First, you have to protect the Rippers so that at least 4 (I think) charges are attached. Then just fire at one of them (you may want to deal with all the surrounding fighters before doing that). Hitting "A" will highlight the charge as your primary target, so you shouldn't have any probs locating it. In the majority of cases, ppl chose a Shroud for this mission due to its cloaking ability - the ion cannon is a nasty thing to deal with. Have fun! You may also want to read the strategy guide (or walkthrough) for that mission. It's the last and the toughest one.

As zlo mentioned, the rippers have to be protected.
I tend to kill all the fighters first, ignoring any commands given followed by any turrets that point up towards the top of the base, especially nr the bit where the torps hit. I have found it is the turrets that get most of the rippers. After that, take out any fighters that jump in, starting with the nearest to the rippers. That should get you past that part, checking out the guide will help too. Try the shroud if the ion cannon keeps zapping you.
After that bit the fun really starts!!!!!

Happy hunting

Skymouse

I actually stayed in the asteriod base when it explodes.. i have 25% health left but still manage to limp home but cant face the fighters because radars busted..

I Don't want To end up in corpse early because YOU were daydreaming.. any bad faction pilot