<div class="htmlview paragraph">This paper discusses two types of sink temperatures as approved by the Space Station Freedom (SSF) project. The two types of sink temperatures are the “black body sink temperature”, and the “gray body sink temperature”. These sink temperatures apply to both individual nodes and a group of nodes (component). Computation of these sink temperatures are discussed as well as their applicability in differential equations. Included with the derivation of the sink temperature equations are the assumptions made for defining each formula.</div> <div class="htmlview paragraph">Both sink temperature methods described yield identical surface temperature results when applied with the correct radiation conductors. Black body sink temperatures are the recommended method of computing sink temperatures because applying them in thermal analysis is straightforward. Gray body sink temperatures are sometimes used because they are not dependent on as many parameters as black body sink temperatures and are easier to compute, but careful assumptions must be made when using gray body sink temperatures in radiative thermal analysis.</div>