sentences:  The envelope is fabricated from polyester cloth, coated inside with saran film for gas retention and outside with polyurethane loaded with titanium dioxide for durability.The gondola is a kevlar-reinforced moulding, suspended from the top of the envelope by kevlar cables.The pilot controls elevators and rudders on the tail surfaces by fore-aft and lateral movement of a yoke, via a manual, cable-operated system.