An ancient technology repurposed.
One prominent example of this has been catalogued by the UNSC as “MDT” or Modular Dispersal Technology—the large-scale, rapid disassembly of Covenant starships while in a vacuum and, in some situations, during the course of a battle. When vessels were significantly damaged or suffering from atmospheric breaches, rather than immediately return the craft to a shipyard or repair center, the Covenant could simply detach noncritical sections and continue to operate—some ships even retaining the capacity to enter Slipspace.
Due to the modular architecture of Covenant ships, a damaged vessel could fully function even after scuttling large portions of its hull and general mass. Upon returning to a refitting station, the ship could then be reconstituted and redeployed with minimal loss. This functionality is easily reconciled with the Covenant’s broader design rationale, in that they commonly prefer the use of redundant, simultaneous components, rather than a centralized system for their ships.
Although the Forerunners may have used this technology for this purpose from time to time, it has been determined that the origin of MDT was the Forerunner war with the Flood and that MDT appears to have a different primary purpose for the Forerunners. When the shield and hull of a warship were breached by the implacable parasite, the Forerunners would initiate this measure to disable and scuttle compromised sections of their ships during the battle. The vacuum would then claim whatever Flood remained in the inert portions, providing a somewhat pyrrhic victory against the parasite’s overwhelming dominance.
Only a handful of instances have been recorded in which the Covenant have effectively used this technology in naval combat—and even those remained clouded in mystery.