Also keep in mind EACH SENTINEL is ONLY equipped with a heavy laser cannon (its not even on par with a TURBO laser from a capital ship in STAR WARS when fired in CONJUNCTION with others. And COVENANT vessels DONT have ray shielding (or to my knowledge ANY energy shields of ANY kind). I will run the actual numbers and account for thermal dynamics (though with a LASER or ENERGY based weapon the initial impact IS the strongest part of the reaction; lets not forget ENTROPY) ---> death star vs sentinel array An yea MAC rounds under SUSTAINED fire Might be on par with an asteroid impact but you would need to sustain fire FOR SOME TIME! (Keep in mind ANY asteroid impact is 500x MORE force/blast produced than A NUCLEAR WARHEAD of same YEILD!)