Abstract: A dual compensation chamber loop heat pipe(DCCLHP) was developed to solve the problem of the relative orientation limit between the evaporator and the compensation chambers. The construction of the evaporator and the compensation chambers was presented.The concurrent design method of the working fluid charge mass and the compensation chambers volumes was introduced.Within a certain temperature range,the DCCLHP can not only start up and operate normally at any orientation,but also can avoid the most difficult startup situation.The operation and the thermal control characteristics of the DCCLHP were investigated.Test results indicate that in some heat load regions,the operating temperatures vary with the relative orientation between the evaporator and the compensation chambers.It was explained by the thermal equilibrium of the compensation chambers and the usage efficiency of the return liquid subcooling.The test results and discussion of the DCCLHP suggest that part of the return liquid subcooling that cools the liquid to be locally subcooled must be considered in the mathematical modeling of the LHP.Another suggestion is that an effective method to decrease the operating temperature or thermal resistance of the DCCLHP is to enhance the heat transfer between the return liquid and the fluid in the saturated compensation chambers is to increase the usage efficiency of the return liquid subcooling.