How do you blow up the send the asteroid away in dead space

You don't blow it up, you send it away so people can pick up the SOS. You must slow down the engines that have light going towards the asteroid and shoot them ( they blow up.) Watch out for aliens that come your way. Next you jump on the asteroid and get out of the ship. Then you destroy the generators outside. You can finally plant the SOS on the asteroid. Then you go back inside and go to the controll room and launch the asteroid. As soon as you do that, aliens show up, so be careful...