Due to current industry trends in electronics component design and packaging, spacecraft are becoming smaller and more powerful. As a result, spacecraft power densities are foreseen to increase dramatically in the coming years, and thermal considerations are expected to become an even larger problem than on current spacecraft. Todays thermal control technologies will soon be too inefficient or ineffective to meet tomorrows needs, and innovative thermal management solutions are required to ensure that thermal considerations do not limit spacecraft capabilities on future missions. This proposal presents a revolutionary new thermal control solution in development at the Air Force Research Laboratory Space Vehicles Directorate, called IsoTherm, which provides a 100X increase in thermal performance by integrating a two-phase (liquid/vapor) cooling loop within the ribs of an isogrid structural panel, and this is achieved with no detrimental effect on the stiffness/mass ratio of the panel. The objective of the experiment proposed is to quantify the performance of the IsoTherm system, and the electrohydrodynamic (EHD) pumps that power it, in a microgravity environment.