Sessutum

Sessutum is a term used in speculative materials science and science fiction to denote a hypothetical crystalline material with extraordinary mechanical strength and energy storage capabilities. In most treatments, sessutum is imagined as a dense, polycrystalline ceramic or ceramic–metal composite whose lattice structure enables rapid electron transport while remaining resistant to extreme temperatures and radiation. There is no verified evidence that such a material exists in the real world.

Described properties vary by source, but sessutum is commonly attributed a very high specific strength, near-zero thermal expansion, and the ability to store electrical charge within its lattice or interfacial regions. Some descriptions assign superconducting-like conductivities at elevated temperatures; others limit its conductivity to highly efficient charge mobility without true superconductivity. Typical proposed applications include spacecraft hulls, radiation-shielded habitats, and compact energy storage systems.

Origin and usage: The term appears in speculative texts and in science fiction dating from the mid-20th century onward. It is routinely employed as a plot device to enable durable, lightweight components and efficient power storage in imagined technologies. In academic discussions, sessutum is often treated as a thought experiment illustrating challenges in designing real materials with simultaneous strength, lightness, and energy density.

Etymology and status: Sessutum is a constructed term without an established etymology or taxonomic basis. It is not recognized as a real mineral or material by any scientific registry, and no experimental synthesis has been reported.