Fact sheet number: FS-2002-10-162-MSFC
This fluid physics experiment will be performed in the Microgravity Science Glovebox, which has an enclosed workspace that provides power, computer interfaces and other resources for experiment operations. It is also equipped with glove ports that enable the crew access to operate the experiment. The purpose of this experiment is to obtain basic data on magnetorheological (MR) fluids -- a new class of "smart materials" or controllable fluids. Due to the quiet, rapid-response interface that they provide between mechanical components and electronic controls, MR fluids can be used to improve or develop new brake systems, seat suspensions, robotics, clutches, airplane landing gear and vibration damping systems.
In the low-gravity environment created as the International Space Station orbits Earth, it is possible to study the way small magnetic particles interact in these fluids. On Earth, gravity causes sedimentation, which means heavier, or larger groups of particles sink while lighter ones remain suspended. Onboard the Space Station, the small magnetic particles will form three-dimensional microstructures that are unaffected by sedimentation. A pulsed magnetic field will be used to mimic the forces applied to these fluids in real applications, such as in active feedback systems. A pulsed field also tends to produce intricate, thick structures with different properties than structures produced by a constant magnetic field. These structures can provide stiffness or rigidity to the fluid.
Before the flight, a coil assembly with a small precision rectangular borosilicate glass vial, 50 millimeters long by 1-millimeter internal square, is filled with the magnetorheological fluid.
Each fluid sample will include a suspension of small, magnetizable particles of pre-measured sizes in very pure water. The crew will install these coil assemblies along with support hardware and cameras for viewing the samples in the Microgravity Science Glovebox.
The crew will set a specified electrical current and frequency that will produce a pulsed magnetic field inside the coil. This magnetic field will cause the particles in the fluid to group together, or aggregate, and form microstructures inside the fluid.
For a period of about an hour, a video camera will record the microstructures as they form. This video will be sent to the Telescience Support Center at NASA's Glenn Research Center in Cleveland, where scientists can observe the microstructures as they form and change. Later, it will be returned to Earth for more in-depth analysis.
The crew will install three different coil assemblies, each with vials containing different particle sizes. Nine tests will be run per coil for a total of 27 experiment runs.
This is the first time this experiment has been conducted in space. It will provide fundamental data on the way the particles and aggregate structure in the fluid respond to an external magnetic field that is repeatedly switched on and off. When these fluids are used in braking systems and for other electromechanical devices, they are often exposed to such fields that affect their operations.
The data from the experiment can be used to test theoretical models of the structure of suspensions of small particles in applied fields. By understanding the complex properties of these fluids and learning the way the particles interact, scientists can develop more sophisticated methods for controlling these fluids and using them in a variety of devices.
Then, scientists can improve the types of fluids used in existing braking and vibration damping systems. They may even be able to design new robotics systems and use the fluids for novel applications such as seismic dampers to make high-rise structures more resistant to earthquakes.
For more information on this experiment and other Expedition Six Space Station investigations, visit: