Investigating 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)
National Aeronautics and Space Administration (NASA)Sponsoring Organization
Human Exploration and Operations Mission Directorate (HEOMD)Research Benefits
Information PendingISS Expedition Duration:
November 2002 - September 2006Expeditions Assigned
6,7,12,13Previous ISS Missions
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 Applications
The 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 Protocols
The 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