It is also used to power a time portal on Krulmuth-B. The NX-01 Enterprise partly consists of horonium, an element that is rare to find but can be synthesised. Federation ships in the 32nd century also used this material in their construction. Neutronium is considered to be virtually indestructible the only known way of stopping the planet-killer is to destroy it from the inside via the explosion of a starship's impulse engines.
The planet-killer in ' The Doomsday Machine' had a hull made of solid neutronium, which is capable of withstanding a starship's phasers. The fictional metals duranium and tritanium were referred to in many episodes as extremely hard alloys used in starship hulls and hand-held tools. Like other aspects of stories in the franchise, some were recurring plot elements from one episode or series to another. This is a list of notable fictional materials from the science fiction universe of Star Trek.
