Heat switch. The switch includes a magnetostrictive member and a coil arranged to apply a magnetic field to the magnetostrictive member to cause the member to change from a first state to a second state of elongation. A heat conductive flexible structure is coupled to the magnetostrictive member so as to change its lateral extent in response to a change from the first state of elongation to the second state of elongation of the magnetostrictive member. A heat conductive housing is adjacent to at least one surface of the flexible structure so that the at least one surface of the flexible structure is in contact with the housing in one state of elongation of the magnetostrictive member and out of contact with the housing in the other state of elongation of the magnetostrictive member. The switch controls the flow of heat from a relatively warmer surface to a relatively colder surface.
