A flexible tube, pipe, or cable that supplies crucial elements, such as oxygen, information, rocket fuel, and electrical supplies. During extravehicular activity, an umbilical cord runs from the spacecraft to the astronaut's chest pack, supplying high-pressure oxygen. This cord also contains radio wires, a hose that delivers nitrogen to the manned manoeuvring unit (MMU) for the jet gun, and a strong nylon tether to keep the umbilical cord from pulling loose.