[quote]How in the hell did Earth's defenses fail in the autumn of 2552?[/quote]Covenant ships are vastly superior to UNSC tech. Despite the sheer number of defenses, it was inevitable that the Covenant would breach UNSC defenses. However, considering that Lord Hood managed to contest the Covenant in the lunar perimeter even after the ODG began to shatter for a month is very impressive. Had the Covenant not shattered the ODG, Earth would have held out for a considerable time. [quote]300 of the most powerful ODP stations in fiction plus Home fleet support should have kicked some serious ass. (Please don't say the Covenant planted anti matter bombs on every single ODP station.)[/quote]Ah I see what you want to know now. Okay, so the ODG was made up of 300 SMACS arranged in clusters of 3 around the planet. That's 100 clusters. Each cluster was was assigned to cover a given section of space. Any deviation of that coverage might weaken the defense perimeter. As the cluster above Cairo was neutralized, a hole was opened up in its firing pattern allowing Covenant ships to breach the perimeter and presumably destroy other clusters from beneath the ODG. [quote]I know Covenant ships are generally more maneuverable than any comparable craft, but Regret's expeditionary fleet should have been pulverized space debris inside the first hour.[/quote]Which is why Regret employed ingenious strategies. [quote]Also, please explain why the ODP grid's petaton kinetic yield is completely ineffectual against the Mantle's Approach while a simple mining survey charge annihilates it? This, along with the inexplicable armor change in Halo 4 endlessly infuriates me.[/quote]Armor plating is placed on the outside, not the inside. A more complex answer is that a large portion of the ship's power was being used to power the composer's systems. Disrupting it could have caused a chain reaction of explosions and power loss. Additionally, Forerunner ships are held together by hard light. It could quite possibly be that the ship literally fell to pieces. [quote]Double Meta Edit: Is this the new Universe Forum as well? If so, cool.[/quote]Pretty much. Halo lore all day 'erry day.