Abstract: A composite panel with a thermosetting cellular matrix, a method for manufacturing said panel, and a structure for covering a wall that is formed from an assembly of such panels. The structure provides the wall with heat insulation against cryogenic fluids and/or protection against fire or flames and/or sealing against the fluids. A panel having a thermosetting cellular matrix, includes at least one substrate that includes short, non-woven basalt fibers and is impregnated by the matrix. The panel is such that the at least one substrate includes a plurality of non-woven layers stacked to a stacking thickness. The non-woven layers each include the short basalt fibers and are needled through the thickness without using thermoplastic fibers.