Abstract: A ground-based system and apparatus useful for simulating a high altitude hypobaric environment, the system including a plurality of hypobaric test chambers of different sizes that can be quickly and efficiently evacuated by means of a depressurization apparatus further comprising a plurality of operatively connected vacuum tanks to produce, selectively adjust and sustainably control the hypobaric environment for a desired interval ranging from minutes to weeks. The subject test chambers each have at least one large viewing port providing clear interior visibility to an external observer and desirably also include apparatus for conveniently maneuvering payloads into and out of the test chambers.