Abstract: Methods and systems for controlling and maintaining the pressure in an ultra-stable optical resonance cavity are disclosed herein. A method for controlling and maintaining the pressure in an ultra-stable optical resonance cavity, for example, comprises providing an ultra-stable optical system housed in a vacuum housing enclosure and a pumping system in communication with the vacuum housing for maintaining a pressure in the vacuum housing less than 1×10?6 Torr. The pumping system may comprise combination pumping achieved with the simultaneous use of a getter pump and an ion pump that provide passive and active pumping, respectively. The pumping system may also comprise passive pumping only with a getter vacuum pump only. The present invention, disclosed herein, achieves passive, power-free pumping in ultra-stable laser systems thereby enhancing the portability of such systems.