A space systems engineer is testing the thermal response of a titanium probe head, Apex-6, inside a vacuum simulation chamber. The probe head contains an internal electric heater which is switched on at t=0t = 0t=0 and supplies energy at a constant rate.
Explain, in terms of energy transfer and thermal radiation, why the temperature of the probe head Apex-6 eventually levels off and reaches a constant value of 110 ∘C110\ ^\circ\text{C}110 ∘C even though the heater remains switched on.