Abstract: An improved solar panel for a spacecraft. The solar panel has a rigid base, at least one row of solar cells, and at least one elongated, collapsible, self-deploying reflector. Preferably, a plurality of rows and the reflectors are mounted on the face of the base and are generally parallel to each other in an alternating fashion. The deployed reflector forms a triangular shape having a first and second reflecting side that reflects radiation onto adjacent rows of solar cells. The collapsible reflector has a reflector sheet and an erector that deploys the sheet to form the triangular shape. The sheet is mounted to the base along its two lengthwise edges. The erector is mounted to the base beneath the sheet and adjacent to one of the sheet's lengthwise edges. The erector has a rigid erector arm that tilts upwardly to engage the underside of the sheet and to deploy the sheet into the triangular shape.