Parachute cord (also paracord or 550 cord when referring to type-III paracord) is a lightweight nylon kernmantle rope originally used in the suspension lines of parachutes. This cord is useful for many other tasks and is now used as a general purpose utility cord by both military personnel and civilians. This versatile cord was even used by astronauts during the 82nd Space Shuttle mission to repair the Hubble Space Telescope. The braided sheath has a high number of interwoven strands for its size, giving it a relatively smooth texture. The all-nylon construction makes paracord fairly elastic. Current technical standards for the manufacture of cord for use in parachutes are published by the Parachute Industry Association. The US military MIL-C-5040H standard required the material to be nylon. Similar styles of cord are manufactured with other materials such as polyester.