Section One: Cause
The Death Star was lost with all hands (save two surviving TIE pilots whose reports are attached in Appendix 3) following a catastrophic failure of its primary power core. Simulation reveals that reactor coolant ignited, causing a sudden loss of core containment. The core exploded, sending molten debris, hot reactor plasma, and radiation throughout the Death Star structure. This, in turn, ignited a number of other systems resulting in secondary explosions throughout the station. Total failure of the Death Star took less than a second after the initial core breach.
Reactor coolant was ignited by a proton torpedo fired from a Rebel controlled X-wing class starfighter (see Appendix 4 for details on known Rebel vehicles, including the X-wing). Rebel propaganda suggests the fighter was flown by Rebel pilot Cmdr. Luke Skywalker, though this cannot at this time be confirmed (see Appendix 5: Intercepted Rebel Reports). The torpedo entered an auxiliary thermal exhaust port on the external structure. When it exploded it ignited reactor coolant, causing a chain reaction that resulted in core failure and ultimate loss of the station.
Rebel fighters were able to penetrate the Death Star defenses due to an oversight in shield design. The Death Star's defenses were designed to defend against large scale cruiser attacks, but were easily penetrated by small fighters. Its point defense teams were unable to target the maneuverable fighters. Attempts to intercept them with the Death Star's own TIE squadrons failed in part due to loss of maneuverability close to the Death Star structure (see Appendix 4 for a comparison of X-wing and TIE maneuverability close to large structures).
Section Two: Origin of the Flaw
It is natural at this point to wonder how such a disastrous flaw could exist on such a massive project. In fact that statement has its own answer. Investigation reveals that the flaw that destroyed the Death Star was a result of a breakdown in communication.
Construction of the various elements began well before design was completed on others. This was considered necessary by Imperial oversight to complete the massive station in a reasonable amount of time. As a result the primary weapon, the inappropriately named "Super-Laser," was not yet completed when the power design team had completed their task.
The super laser ultimately required far more power than originally anticipated. To compensate a larger power reactor was purchased to meet the new needs. The power contractor's report on the change was never submitted to the thermal design team, who completed design using the heat output of the original core.
Simulations revealed a serious over-heating issue in the core during the final checkout of the thermal control system. To compensate the thermal design team added an auxiliary thermal control duct to the core. A flash evaporator was added to remove excess heat from the core during peak power utilization, typically firing of the primary weapon.
Addition of the core and the new thermal vent was noted by the contractor oversight panel. It did not, however, result in any change to the existing structural blueprints, which had been finished for some years. The addition of the new vent was noted only during installation of the thermal control system into the already finished superstructure.
A technician installing the thermal control system noted that there was no opening for the new thermal exhaust duct. He submitted a change request to structure engineering management, who observed no structural reason why a new hole could not be added. As the project was already behind schedule and over budget contract management approved the request with no additional analysis. The vent was drilled into the surface of the Death Star and the auxiliary duct installed.
At no point were the point defense or shield grid contractors informed of the changes. It is not required by Imperial guidelines for contractors to communicate with each other and contract oversight saw no reason to share the work of different contractors. The thermal control team was never informed that they duct might come under fire. The power design team was never informed that the reactor coolant was potentially combustible.
Section Three: Institutional and Oversight Failures
The failures of analysis and communication observed in the preceding section are not the only breakdowns the investigation has discovered in the Death Star design. A number of potential flaws, though less severe, were neglected or dismissed by leadership.
A spirit of invulnerability pervaded the entire Death Star project, up to its demise. The potential for disaster was ignored because all involved considered failure impossible. The original design for the Death Star was overly optimistic and changes to the design were simply accepted with little or no question.
Partially to blame is Imperial doctrine regarding capital ships. Imperial doctrine relies on increasingly large cruisers for massive bombardment, overwhelming enemy ships and bases, and establishing superior presence. Contrast with the Rebel hit-and-run fighter assault doctrine, Imperial fighters and bombers are used primarily in support roles.
As a result the Death Star defense teams had a "bigger is better" approach to design. They did not consider small ships a threat because Imperial doctrine doesn't consider them a threat. Their design never considered the idea that the Death Star's armor might have a weak point. Minimal defense of the exhaust port was in place only because regulations required ray-shielding of all surface openings on any Imperial station or capital ship, not because the potential for failure was noted.
Over-confidence on the part of the contractors and project leaders led to dismissal of potential design flaws. Pressure from Imperial leadership for completion of the project, which was behind schedule and over budget, also contributed. Again those in power did not consider project failure a possibility, so they ignored requests for additional time and funding. As a result additional tests and simulations were cancelled.
Section Four: Conclusions and Recommendations
A full list of technical design recommendations for the "Site B" Death Star is supplied in Appendix 7. In short modified reactor design is called for. This change should eliminate the need for coolant, making the core inaccessible to enemy forces once the superstructure is complete. Tighter defense screens are also required.
More important is an institutional change. Imperial leadership must be aware of the danger posed by small craft and understand the advantages of the Rebel fighter doctrine. The bigger is better attitude has to be overcome, since Rebel forces will consistently deny Imperial forces the sort of head-on engagement those larger vehicles are built for.
Further the spirit of invulnerability must be dealt with. The Death Star was lost largely because none involved in its design, construction, and operation believed it could be lost. If "Site B" is to succeed where its predecessor failed the operators must understand that it isn't invincible. The major concerns at the end of the Death Star's construction were schedule and budget, not survivability. If safety is not made the first priority then the project is doomed to failure.