18th IAA Humans in Space Symposium (2011)
Impacts of Different Methods for Simulation of Weightlessness Conditions on Ground –
Clinostat versus Random Positioning Machine
J. Hauslage, K. Waßer, S. Hoppe, R. Anken, and R. Hemmersbach
Institute of Aerospace Medicine, German Aerospace Center (DLR), Cologne, Germany, Jens.Hauslage@dlr.de
Various ground based methods aim to achieve the status of functional weightlessness. In the current project two
kinds of simulation methods are compared by investigating space-approved model systems. The samples are either
rotated continuously around one axis (2D clinostat) or around two axes with different operational modes (3D
clinostat/Random Positioning Machine). In order to understand what happens during the applied approaches and to
estimate the quality of simulation optical equipments were installed on the experimental platforms, allowing online
observations of the induced phenomena. By studying fast and distinct cellular responses – such as gravitaxis
(orientation) of Paramecium (ciliated unicellular organisms) as well as sedimentation behaviour of immobilized
cells or glass beads – different results were obtained depending on the applied simulation method. In case of
Paramecium 2D-clinorotation induces a homogeneous distribution of the swimming directions of the cells
comparable to the behaviour in real microgravity (TEXUS, MAXUS, IML2-mission). In contrast, a quite different
behaviour is observed during 3D-clinorotation, characterized by an increase in directional turns of swimming cells
and a drifting of immobilized objects, indicating mechanical disturbances. Our results clearly demonstrate that a
critical consideration is absolutely necessary with respect to the phenomena which are induced by ground based
simulation devices.
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