Once the standard pattern of Dreadnought in the [[Great Crusade]]-era, the ability to create new Contemptors is now beyond the [[Adeptus Mechanicus]] or perhaps a closely guarded secret by certain [[Tech-Priest]] factions. At the time of the [[Horus Heresy]] it was a recent design, equipped with advanced energy generators that allowed for enhanced speed and strength as well as defensive energy field systems. These advantages came with a price however, for it requires a higher degree of maintaneance and a catastrophic meltdown may occur if its arc reactor is breached.{{Fn|36}} Some believe that the design may share systems with the dreaded, near-mythical battle-automata of the [[Legio Cybernetica]]. If this is the case, it may explain why so few Contemptors remain in service as of [[M41]]. Those few that still remain in service are relics of the [[Great Crusade]], [[Horus Heresy]], and [[The Scouring]].{{Fn|4a}} In the 41st Millennium, the [[Castaferrum Pattern Dreadnought]] has become the most common.{{Fn|3}}