Thermal diode of central axis comprising: - a first crown ring, intended to be in peripheral contact with a housing forming a heat source, the first crown ring being divided into an even number n of equal angular portions of which half is made of thermally insulating material over at least a part of their thickness and, if necessary, with a phase-change material over a part of their thickness, and the other half each comprising a finned heat sink which extend radially with respect to the central axis X and a phase-change material filling each of the spaces between two adjacent fins; each of the portions with finned heat sink filled with phase-change material being arranged between two portions made of thermally insulating material when n is greater than 2; - a second crown ring, intended to be in peripheral contact with a shell forming a cold source, the second crown ring being concentric around the first crown ring; the second crown ring being divided into a same even number n as that of the first crown ring, of equal angular portions of which half is made of thermally insulating material, and the other half of thermally conductive material, each arranged between two portions made of thermally insulating material when n is greater than 2; one and/or the other of the first and second crown rings being mounted to rotate about the central axis; - at least one means for rotating about the central axis one and/or the other of the first and second crown rings, so as to superpose: • in a conducting regime, the portions made of thermally insulting material of the second crown ring on those of the first crown ring and, simultaneously, the portions made of thermally conductive material of the second crown ring with those with finned heat sink filled with MCP material of the first crown ring and thus allow the heat flux from the housing to pass to the shell, or • in a blocked regime, the portions made of thermally insulating material of the second crown ring on the portions with finned heat sink filled with MCP material of the first crown ring and, simultaneously, the portions made of thermally conductive material of the second crown ring on the portions made of thermally insulating material of the first crown ring and thus block the heat flux from the housing to the shell, which is absorbed by the MCP material filling the spaces between fins of the portions with finned heat sink. - a first crown ring, intended to be in peripheral contact with a housing forming a heat source, the first crown ring being divided into an even number n of equal angular portions of which half is made of thermally insulating material over at least a part of their thickness and, if necessary, with a phase-change material over a part of their thickness, and the other half each comprising a finned heat sink which extend radially with respect to the central axis X and a phase-change material filling each of the spaces between two adjacent fins; each of the portions with finned heat sink filled with phase-change material being arranged between two portions made of thermally insulating material when n is greater than 2; - a second crown ring, intended to be in peripheral contact with a shell forming a cold source, the second crown ring being concentric around the first crown ring; the second crown ring being divided into a same even number n as that of the first crown ring, of equal angular portions of which half is made of thermally insulating material, and the other half of thermally conductive material, each arranged between two portions made of thermally insulating material when n is greater than 2; one and/or the other of the first and second crown rings being mounted to rotate about the central axis; - at least one means for rotating about the central axis one and/or the other of the first and second crown rings, so as to superpose: • in a conducting regime, the portions made of thermally insulting material of the second crown ring on those of the first crown ring and, simultaneously, the portions made of thermally conductive material of the second crown ring with those with finned heat sink filled with MCP material of the first crown ring and thus allow the heat flux from the housing to pass to the shell, or • in a blocked regime, the portions made of thermally insulating material of the second crown ring on the portions with finned heat sink filled with MCP material of the first crown ring and, simultaneously, the portions made of thermally conductive material of the second crown ring on the portions made of thermally insulating material of the first crown ring and thus block the heat flux from the housing to the shell, which is absorbed by the MCP material filling the spaces between fins of the portions with finned heat sink. • in a conducting regime, the portions made of thermally insulting material of the second crown ring on those of the first crown ring and, simultaneously, the portions made of thermally conductive material of the second crown ring with those with finned heat sink filled with MCP material of the first crown ring and thus allow the heat flux from the housing to pass to the shell, or • in a blocked regime, the portions made of thermally insulating material of the second crown ring on the portions with finned heat sink filled with MCP material of the first crown ring and, simultaneously, the portions made of thermally conductive material of the second crown ring on the portions made of thermally insulating material of the first crown ring and thus block the heat flux from the housing to the shell, which is absorbed by the MCP material filling the spaces between fins of the portions with finned heat sink.