This analysis created a model to predict the voltage difference between the ISS and the plasma background. The ionospheric plasma interacts with the ISS solar arrays and conducting surfaces, causing excess charge to be accumulated, thus creating the potential difference. This model will be used to predict the ISS floating potentials to assess vehicle and EMU dielectric breakdown.Principal Investigator(s)
Boeing, Houston, TX, United States
National Aeronautics and Space Administration (NASA)Sponsoring Organization
Human Exploration and Operations Mission Directorate (HEOMD)ISS Expedition Duration:
April 2005 - April 2008
11,12,13,14,15,16Previous ISS Missions
The Plasma Interaction Model is a unique investigation, which has not been previously performed.
This experiment was designed to create a model to predict the voltage difference between the ISS and the plasma background. The ionospheric plasma interacts with the ISS solar arrays and conducting surfaces, causing excess charge to be accumulated, thus creating the potential difference. This model will be used to predict the ISS floating potentials to assess vehicle and EMU dielectric breakdown.
The Plasma Interaction Model (PIM) collected measurements of the ionospheric plasma around the ISS using the Floating Potential Probe (FPP) that was mounted outside on an ISS truss until it was jettisoned in late 2005. Data were also collected using the Incoherent Scatter Radar (ISR) data, a ground-based technique for the study of the Earth's ionosphere and its interactions with the upper atmosphere, the magnetosphere and the interplanetary medium (solar wind). These measurements helped validate the models that used magnetic field inputs from the International Geomagnetic Reference Field (IGRF), and plasma environmental parameters from the International Reference Ionosphere (IRI), an empirical standard model of the ionosphere based on all available data sources. Joint investigations with ISR principal investigators at Millstone Hill (USA) and Irkutsk (Russia) have been conducted. Plasma data from a previously launched satellite, Dynamics Explorer-2 (launched August 3, 1981 and collected data through February 19, 1983) can also be used as input into PIM. This plasma database will be increased as more plasma data become available, i.e., from the CHAMP satellite and ISS Floating Potential Measurement Unit (FPMU). Other inputs to the PIM include vehicle coordinates, configuration of solar arrays, conducting area, and the Plasma Contactor Unit (PCU) currents and current-to-voltage relationship.
This Plasma Interaction Model models the interaction of the space-craft, with high voltage solar arrays, to the local plasma environment.Earth Applications
This model will be the standard for solar arrays in space. With an energy crisis upon us, solar power is a viable alternative. Ultimately solar arrays in space create more power than solar arrays on the ground. This model will be invaluable for those seeking to pioneer solar arrays in space for the private sector.
Continue operation of ISS PCU and FPMU to gather test data for various ISS flight configurations and attitudes.Operational Protocols
Data will be collected and analyzed from different inputs, such as the Earth ground stations and ISS. The data points will then be plotted for analysis and interpretation.
The PIM has been used to predict the charge build-up and associated dangers for future ISS solar array configurations. Ground data were collected from various locations around the world. Additionally, historical data—e.g., the IRI 2001 model, FPP data, and the Dynamics Explorer-2 Satellite data, are available. Using these data, the PIM has been able to characterize the peak voltage levels for the various ISS stage builds. (Reddell et al. 2006). (Evans et al. 2009)
Reddell B, Mikatarian R, Kramer L, Alred J, Koontz S, Minow J. Analysis of ISS Plasma Interaction. Proceedings of the 44th AIAA Aerospace Sciences Meeting and Exhibit, Reno, NV; 2006 January 9-12; Reno, NV.
Mikatarian R, Barsamian H, Alred J, Kern J, Minnow J, Koontz S. Electrical Charging of the International Space Station. 41st Aerospace Sciences Meeting and Exhibit, Reno, NV; 2003
Mikatarian R, Barsamian H, Alred J, Minnow J, Koontz S. ISS Plasma Interaction: Measurements and modeling. 8th Spacecraft Charging Technology Conference, Huntsville, AL; 2003
Mikatarian R, Barsamian H, Kern J, Koontz S, Roussel J. Plasma Charging of the International Space Station. 53rd Annual Astronautical Congress, The World Space Congress, Houston, TX; 2002