Press G to change your secondary weapon to Recon Droid. Right click to do your secondary attack and you willl then be in control of the recon droid. Fly it to where you want to do the orbital strike. Right click, You will hear beeping. A few seconds later, laser bolts will come out of the sky to the spot your droid was. If you want, you can switch back to your character (by scrolling the mouse wheel) right after you right click so you can actually watch the bombardment.