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Experiment OverviewInvestigating the Structure of Paramagnetic Aggregates from Colloidal Emulsions (InSPACE) will study the particle dynamics of magnetorheological fluids (fluids that change properties in response to magnetic fields) to help understand adaptable new fluids for use in such applications as brake systems and robotics.
Principal Investigator(s)
Information Pending
Developer(s)
Information Pending
National Aeronautics and Space Administration (NASA)
Sponsoring OrganizationHuman Exploration and Operations Mission Directorate (HEOMD)
Research BenefitsInformation Pending
ISS Expedition Duration:November 2002 - September 2006
Expeditions Assigned6,7,12,13
Previous ISS MissionsInformation Pending
Magnetorheological (MR) fluids are suspensions of magnetizable particles whose properties can be controlled by magnetic fields. These fluids are classified as "smart materials" that transition to a solid-like state by the formation and cross-linking of microstructures in the presence of a magnetic field. The samples prepared for InSPACE were ferrofluid emulsions consisting of iron oxide nanoparticles suspended in a solution of sodium dodecyl sulfate, anionic surfactant and ultrapure water. These samples were comprised of uniform particle sizes of 0.31, 0.40 and 0.66 micrometers. On Earth these materials are used for vibration dampening systems that can be turned on or off. The Investigating the Structure of Paramagnetic Aggregates from Colloidal Emulsion (InSPACE) experiment will visually study the final, fine structure of MR fluids in a pulsed (alternating on and off) magnetic field. This study will help researchers understand the competing forces that govern the final shape of the structures.
The InSPACE coil assembly holds a Helmholtz coil assembly containing sealed vials of MR fluid, the camera/lens assemblies, and the power control. The coil assembly is attached to the "floor" of the MSG. The magnetic fields are applied to the various samples, and the operation of the experiment is monitored via video.
At the practical level, these fluids are used in electromechanical interfaces and devices in which the fluid is operationally exposed to similar fields which can affect their operation. Current commercial MR fluid products include tunable dampers and brakes, while future applications in robotics, clutches, and a host of vibration-control systems are envisioned.
Earth ApplicationsThe study of MR fluids on earth is difficult because the small magnetic particles remain suspended while the sediments (large particles) sink. The low-gravity environment that is provided on the ISS will eliminate the effects of sinking sedimentation. After the magnetic field is applied to a MR fluid, the microstructures form a rigid lattice that causes the suspension to stiffen. The rapid transformation of these fluids without the iron oxide grains clumping have many possible technological applications on Earth, especially for actuator-type devices. This technology has promise to improve the ability to design structures, such as bridges and buildings, to better withstand earthquake damage.
InSPACE will be conducted inside the MSG work volume, and the hardware will be powered (120 vdc) via MSG. The experiment runs will be recorded by MSG's video system. InSPACE is not a fully automated payload. The crew will be responsible for in-orbit operations.
Operational ProtocolsThe crew will set up InSPACE inside the MSG work volume and conduct the 27 experiment runs using the glove ports. They will change out the coils after nine experiments and replace video tapes as necessary.
InSPACE was performed in the MSG during Expeditions 6 , 7 and 13. Nine tests were performed for each Helmholtz coil for a total of 27 experimental runs. The collected data were processed, enabling a quantitative assessment of the structural data, including aggregate sizes and shapes. These are key parameters for defining the aggregate kinetics, and are used to test theoretical models of the microstructures. Furthermore, understanding the complex properties of the fluids and the interaction of the microparticles will enable the development of more sophisticated methods for controlling and use of these fluids. Results suggest that InSPACE runs did not achieve steady-state structures. However, intriguing data suggesting the onset of instability at low frequency was collected. Both of these phenomena will be further addressed in InSPACE 2. (Evans et al. 2009)
Vasquez PA, Furst EM, Agui J, Williams JN, Pettit DR, Lu ET. Structural Transitions of Magnetoghreological Fluids in Microgravity. 46th Aerospace Sciences Meeting and Exhibit, Reno, NV; 2008 Jan 7-10
NASA Image: ISS006E41778 - During Increment 6, Flight Engineer Donald R. Pettit works with the InSpace experiments in the MSG in the U.S. Lab. Don Petit was instrumental in providing the excellent video data for InSPACE. The final InSPACE runs were performed in Expedition 12 and 13 with William McArthur and Jeff Williams respectively and successfully gathering the science data.
NASA Image: ISS006E41756 - View of the InSpace hardware and the MSG in the U.S. Laboratory during Expedition Six
Video Screen Shot of the magnetic field that causes paramagnetic particles suspended in the fluid to collect into long chains. These long chains of clumps can interfere with the emulsions ability to stiffen, as it should when magnetized. This image shows an end view of long chains of an MR fluid exposed to a continuous magnetic field.
Video Screen Shot of the magnetic field that causes paramagnetic particles suspended in the fluid to collect into long chains. These long chains of clumps can interfere with the emulsions ability to stiffen as it should when magnetized. This image shows an end view of the larger aggregates that form during exposure to a pulsed magnetic field. Without the settling effects of gravity, the aggregates grow into complex low-energy structures. Video courtesy of NASA, Johnson Space Center.
Structure evolution in an MR fluid over time while an alternating magnetic field is applied. The far left image shows the fluid after 1 second of exposure to a high-frequency-pulsed magnetic field. The suspended particles form a strong network. The images to the right show the fluid after 3 minutes, 15 minutes, and 1 hour of exposure. The particles have formed aggregates that offer little structural support and are in the lowest energy state.
Video Screen Shot of Expedition 12 Science Officer William McArthur performing InSPACE coil monitor activity to verify the viability of the MR fluid. Video courtesy of NASA, Johnson Space Center.
Video Screen Shot of Expedition 13 Science Officer Jeff Williams performing final session of InSPACE operations during his stay on ISS. Video courtsey of NASA, Johnson Space Center.