In the legendary ending of halo 2 we see the key ship exit slipspace and head for earth, lord hood seeing this tags it for attack, stopped only when chief says he’s on the ship.
In that cut scene to my knowledge, hood is stationed on the cairo still, so if he and the other odps were to open fire on the ship, could they destroy it. Would the defense platforms super macs be enough to penetrate the dreadnought
Maybe, assuming they fire at once, taking down the shields to the ship.
I’m going to go ahead and assume that they couldn’t. A much more powerful UNSC couldn’t stop the Didact’s ship in Halo 4, though the Mantle’s Approach was probably more powerful.
I’m pretty sure they couldn’t touch it. The dreadnought is pretty much a tank, as the Sanghelli couldn’t even bring it down for all those years during the Prophet - Elite war. Of course, that is also in part to all the sentinels stationed on it, but the ship had a huge part to play as well.
IMO, it could have been damaged. Even if the Keyship managed to resist 4 shots of MAC guns and several missiles at the end of The Storm, those were smaller versions of what can be found in an ODP, by far, capable of shooting rounds even 5 times heavier. In Halo 4, Infinity does manage to punch a hole in the Mantle’s Approach hull with her MAC Super Guns, and the Keyship, even in its greater dimension (14 Km in height) is 10 times smaller than the smallest of Mantle’s**Approach dimensions (width of 136 Km) also having a less robust design.