Complex sentence: SG-1 plan to steer the vessel towards Earth to vaporize it during atmospheric reentry, but as the Replicators control the bridge, Carter and Thor suggest instead to install and later detonate an elementary naqahdah-enhanced bomb on the deceleration drive.
Split into simpler sentences: SG-1 plan to steer the vessel towards Earth to vaporize it during atmospheric reentry. Since the Replicators prevent SG-1 from retaking the bridge, Carter and Thor suggest to install an elementary naqahdah-enhanced bomb on the deceleration drive.