The vibration environment on the International Space Station: Its significance to fluid-based experiments

Measurements of the vibration environment on the Russian Mir space station and the US Space Shuttle are compared to the vibration levels predicted for the International Space Station (ISS) and to the vibration levels specifie d for isolated payload racks on the ISS. The vibration levels on the Mir an d Space Shuttle are generally lower than the levels specified in the ISS is olation requirement for the isolated racks and much lower than the levels p redicted for non-isolated racks. Next a summary is given of several materia ls science and fluid science experiments performed on the Mir and the Space Shuttle and designed specifically to examine the sensitivity from mug to m g vibrations in the frequency range 1 Hz to above 100 Hz. These experiments were performed using the Microgravity Vibration Isolation Mount (MIM) oper ating in one of the three modes: isolation mode, non-isolation mode, and dr iven mode. Significant differences were obtained for the isolated versus th e non-isolated experiments and for the driven mode experiments. This sugges ts that the current ISS vibratory specification, which can be achieved only through the use of isolation systems, is not conservative for many materia l science and fluid science experiments. (C) 2001 Published by Elsevier Sci ence Ltd.A