Abstract: The consumptive heat dissipation is an essential way for the spacecraft thermal management in space missions, especially for spacecraft without efficient radiation area. However, this means a large amount of working fluid consumption in the long-duration space missions, as an important issue for the future deep space explorations. Here, we propose a emission-free heat dissipation concept for the long term use in space missons. Firstly, a series of experiments are conducted based on microporous membrane evaporation, to test the heat dissipation performance of the system under different vacuum backpressures. A flexible vapor collector prototype is built to absorb the evaporated water vapor, and to carry out the emission-free evaporation experiments for the evaporator-collector combination. The test results indicate that the microporous membrane evaporator works efficiently with the flexible vapor collector, and its heat dissipation ability increases with the rise of the fluid inlet temperature, while it linearly decreases with the increase of the backpressure. It is concluded that the heat dissipation ability of the emission-free evaporative heat dissipation system will not be damaged as long as the vapor absorption velocity exceeds the evaporation velocity.