Abstract: The thermal environment for deep-space-exploration liquid rocket engine (LRE) was analyzed. It was found that high heat flux could be eradiated to the explorer from the nozzle of LRE. The thermal resistance material was used to prevent heat radiation onto the explorer. When the engine was coated with thermal resistance material,the nozzle wall temperature could be higher than wall temperatures without coating. The current analysis showed that,the increased nozzle wall temperature was still in the allowable range for engine thermal protection. The computational methods of current paper were validated by hot-fire testing. The results were in good agreement with hot-fire measurements.