Test of the Basic Principles of Mechanics in Space (Thebas)
Research Area: Student-Developed Investigations
Expedition(s): 7 and 8
Principal Investigator: ● Ana Laveron Simavilla, Universidad Politecnica de Madrid,
Spain
RESEARCH OBJECTIVES
Test of the Basic Principles of Mechanics in Space (Thebas) prepares a video for educational use
that would illustrate the principles of dynamics ranging from the classic mechanics of solid bodies
to the continuous media mechanics. The experimental setup used to perform the experiment
consisted of transparent closed containers (having the same size and total mass) filled with solid
spheres of different sizes that were periodically oscillated in one dimension.
RESULTS
The figure (left) is a sequence of the
experiment container with 48 spheres: (a)
The spheres coming out of the small
holder, (b) the container sliding to the end
of the sliding guide, (c) the container in
motion, and (d) the configuration after the
stop of oscillation. There is a difference
between spheres distribution in (c) and (d).
The behavior of the spheres in (d) was due
to electrostatic effects that affected the
motion of the spheres inside the container
in a way that was not expected, changing
the dynamics of collisions between
spheres and between the spheres and the
container. This effect was more important for the containers with higher number of spheres.
Another problem was that the lubricant was too viscous and the guide did not slide properly,
reducing oscillation displacement. For safety reasons all the sliding parts of the experiment had
to be lubricated by a specific lubricant, but it was not possible to test the hardware with the
lubricant in advance.
Several improvements could be made in the future. Proofs with different allowed lubricants
should be performed in advance to achieve the desired slide. An important part of the
experiment was the study of the container with the fluid; therefore, a triple level of
containment container would need to be designed, to fulfil the safety specifications in the
International Space Station. Finally, a study of the materials to be used would need to be done
to avoid the electrostatic forces, irrelevant in the ground experiments but important in
microgravity conditions.
Sequence of experiment images showing spheres being
accelerated. ESA image.