© by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.In this paper, a comparative study is made for cooling aerospace plane, using liquid HZ, NHs, and Kr. The study includes the cooling for the stagnation point, the leading edges for wings, engine and other parts of the aerospace plane that are close to the leading edges. Laminar case for the stagnation point and both laminar and turbulent cases for the leading edge heating have been considered. The amount of heat rate (total, radiative and convective) and the mass of liquid coolant needed for cooling are calculated. A design of minimum inlet-outlet areas for the amount of liquid needed for cooling, is made with the consideration of the coolant's physical constraints in liquids and gaseous states. When compared to the other coolants, hydrogen is found to be the superior candidate for cooling aerospace plane.