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Magos Biologis Data Files
Crossref: Adeptus Mechanicus Data File System

A Comparison of Tyranid Mycetic Adaptations to Marine Drop Pod Technologies [STC67D651] for Orbital Planetary Drops.

The difficulties encountered by free fall decent from orbit to terrestrial landing are nothing if not daunting. The tremendous speeds, heat and inertia generated must be dissipated while allowing for the effective deployment of forces. Despite the radically different origins of the two forms discussed, they employ strikingly similar methodologies to eliminate or circumvent these problems. Both also address similar tactical concerns ranging from high altitude evasion to rapid deployment once landfall is made.

Heat Shielding

The initial concern is heat shielding and both forms are smooth to limit friction and maximize initial velocity to avoid enemy fire and interception. The standard marine drop pod is capable of withstanding normal reentry with less than a 3 degree variance in internal temperature thanks to extensive ceramic heat sinks and insulation materials. Heat shielding is jettisoned when the retrorockets are fired. Tyranidic mycotic cysts have ablative layers of shielding which sloth off as the external temperature reaches critical levels. Examination of pods indicated that temperature variance is about 5 times the marine standard but still quite survivable.

Velocity Reduction

Deceleration becomes an issue as the pod plummets towards the target zone. Tyranidic Mycotic cysts deploy thin loops of silk-like proteins, over 300 meters long, that act as minimal parachutes. While the forces endured by marines at impact would cripple or kill a normal human, those to which the tyranids are subjected would likely do the same to a marine. Impact inertial is roughly double that of the standard heavy assault drop pod. Retro rockets on space marine pods fire in the last stages of decent to allow for a survivable landings.

Attitude Adjustment

An internal depleted uranium gyroscope holds the prescribed attitude during the free fall within marine drop pods. External vanes observed within the tyranid systems act as the only form of attitude control other than the cursory stabilization afforded by the deceleration technique. The deceleration technique employed by the mycetic cysts contributes significantly however.

Inertial Dissipation

Both tyranid and marine drops have the difficult requirement of
absorbing the inertia of the fall without critical injury or damage to
the payload.  Both employ strikingly similar methods.  The cysts
cavities are filled with a viscous gel, and the cargo is suspended above
the floor of the chamber.  When the mycotic cysts impacts the planet
surface, be it earth, stone, or water the cargo shifts through the
matrix which absorbs much of the kinetic energy.  Marine drop pods have
fall arrestors which absorb much of the energy, this can be coupled with
a gel matrix in some later pod designs.


Explosive bolts are triggered upon impact allowing the outer hull to fall away for easy evacuation from the pod within seconds. The tyranidic system incorporates a powerful corrosive cocktail encased in a resistant lipid layer. Upon impact the lipid layer fragments releasing the corrosive agent that quickly eats through the seams of the cyst. The gel mixture within the cyst in unaffected by the corrosive enzymes and protects whatever cargo in held within. [A very similar mechanism to the one utilized in the biocannon projectiles, only the mixture is even more virulent and the entire cavity is filled with the mixture.] This is the reason for the fragile nature of the pods when subjected to direct fire weaponry. Sufficient jarring impact can initialize this chain reaction causing the cysts to break apart within the higher atmosphere.

[Note: several tyranidic organisms have been known to survive crashed cysts and even extreme free fall. Caution is advised in all cases.]

Magos Biologis Salk, Head Xenobiology
Draco Legion Biomedical Research station: NewHallefuss
Grand Artificer Keplar
Talos Forge World Command and Control Center