The effect of vibration noise in space relevant experiments

The experiments performed were initiated as a part of the post-flight investigations after the "PROTO" experiment performed on IML-1. The present experiments were performed with protoplasts prepared using the same standard isolation procedures as for the IML-1. The protoplasts were vibrated for 24 h with and without air bubbles in the protoplast cultivation bags and in the range of 1 to 20 Hz with 4 mm amplitude. The vibrations were found to have a negative effect on the viability of the protoplasts in bags without air bubbles and the vibration threshold seemed to lie around 20 Hz. Air bubbles are likely to cause cavitation-like conditions, thus increasing the mechanical strain on the free-floating protoplasts. During the 30 days microgravity mode on the ISS, mechanical vibrations would not be expected to have a significant influence on potential protoplast experiments. Experiments with durations overlapping the rendezvous and reboost mode may be exposed to critical vibration levels.