Heat transfer device and spacecraft comprising such a heat transfer device

A heat transfer device of a spacecraft configured to transfer heat between a first object and a second object, comprising:

• a housing having a first main wall and a second main wall, the first main wall is configured to be in direct thermal contact by conduction with said first object, the second main wall is configured to be in direct thermal contact by conduction with said second object, said housing comprising a sealed internal cavity, a dielectric liquid contained in the internal cavity, and a mixer configured to set said dielectric liquid in motion,
• the heat transfer device is configured to be switched between a first state in which the dielectric liquid is stagnant and a second state in which the dielectric liquid is in motion and transfers heat by forced convection between the first main wall the second main wall,
• the mixer comprising at least two electrodes arranged with a spacing between one another and immersed in the dielectric liquid, wherein the at least two electrodes are each formed by a first grid extending in a first plane and a second grid extending in a second plane, the electrodes and the liquid forming an electrohydrodynamic system, when the heat transfer device is switched into the second state, the dielectric liquid passes across the electrodes during a forced convection movement, wherein the thermal conductance between the first main wall and the second main wall when the heat transfer device is in the first state is four times less than the thermal conductance between the first main wall and the second main wall when the heat transfer device is in the second state.