Although high temperature, liquid metal heat pipe radiators have become a standard component design for many high power space systems, no experimental data on the operation of these kinds of heat pipes in a micro‐gravity environment exists. Issues such as which wick structures or fluids work best in these conditions are unknown. In addition, the freeze/thaw behaviour of liquid metals in zero‐g is not well understood. The purpose of the Liquid Metal Thermal Experiment, known as LMTE, is to fill this gap in our knowledge of liquid metal heat pipes by flying three potassium heat pipes on board the Space Shuttle in 1995. © 1995American Institute of Physics