Patent ID: 6983910

Claim:
A membrane structure comprising: an airtight pressure-resistant gasbag comprising a plurality of spindle-shaped gores of an airtight membrane material, adjacent gores joined together at edges, and a plurality of reinforcing ropes attached to joined sections of the edges, the reinforcing ropes extending along the edges, respectively; and a shape maintaining mechanism configured to maintain the gasbag in a predetermined shape when the gasbag is in a fully inflated state, wherein each of the gores is configured to outwardly protrude between two adjacent reinforcing ropes extending along the edges of the gore, respectively, without elongation of the airtight membrane material, when the gasbag is in the fully inflated state, each protruding gore having a radius of curvature in a direction intersecting the two adjacent reinforcing ropes, the radius of curvature being smaller than a radius of the gasbag, each protruding gore is configured to be subject to a tensile force which is directed in the direction intersecting the two adjacent reinforcing ropes, and each of the reinforcing ropes comprises press portions located at ends of the gore to which the reinforcing rope is attached, and the shape maintaining mechanism comprises a press member configured to press the press portions toward the outside of the gasbag to slenderize the gasbag without elongation of the membrane material.