Extendible structures

An extendible structure having an axis of extension, said structure comprising:

• a plurality of axially spaced-apart station members, each said station member being rigid, and lying in a plane normal to said axis;
• at least three longeron members, each said longeron member comprising a pair of rigid longeron elements, first joint means joining first ends of the elements of each pair of longeron elements to one another for foldable movement relative to each other, and second joint means joining second ends of said longeron elements to respective station members for foldable movement relative to said station member;
• a buckling spring which buckles resiliently and arcuately as an Euler column under end load compression, connected to and between each pair of adjacent first joint means whereby to bias said first joint means away from each other, with a resultant force on each first joint means directed outwardly away from said axis, said station members and adjacent longeron members, when all joint means respective to each pair of joined longeron elements are aligned, forming a respective side panel;
• and
• a pair of first stay members, and a pair of second stay members for each said panel, all of said stay members having a maximum length when fully stretched by tension forces, each one of each pair of said first stay members extending from its respective first joint means of one longeron member to a respective second joint means of the adjacent longeron member of that panel, converging in the direction of fold of said longeron elements, each one of each pair of said second stay members extending from a respective second joint means of said adjacent longeron member to the first joint means of the first-mentioned longeron member, at least said second stay members being non-rigid with respect to endwise compressive forces.