Theses and Dissertations at Montana State University (MSU)
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Item Investigations of the properties of radiation belt electron precipitation observed by the FIREBIRD-II CubeSats(Montana State University - Bozeman, College of Letters & Science, 2022) Johnson, Arlo Thomas; Chairperson, Graduate Committee: John Sample; This is a manuscript style paper that includes co-authored chapters.High energy electrons can be trapped by the Earth's magnetic field in regions known as the radiation belts. Some of these electrons will impact the upper atmosphere and be lost from the radiation belt system in a process known as electron precipitation. This dissertation explores two questions regarding electron precipitation using data from the focused investigations of relativistic electron burst intensity, range, and dynamics II CubeSat mission. The first question was to determine the energy dependence of specific type of impulsive precipitation known as a microburst, which may be a significant contributer to electron loss from the radiation belts. A statistical study of several hundred microbursts was performed and the energy spectrum was found to generally be exponential with a wide rage of possible parameters depending in part on the level of geomagnetic activity. In addition, comparison of this spectrum with the rest of the radiation belt population revealed that microbursts are a more effective loss mechanism for electrons with relatively lower energies. The second question addresses the possibility of inducing electron precipitation using magnetospheric waves artificially generated by a spacecraft. Waves of 3.0 or 8.2 kHz were excited in the magnetosphere by the Demonstration and Science Experiments satellite and a related signature was searched for in the precipitating electrons. There was no evidence of additional precipitating electrons, so an sensitivity estimate was carried out to place boundaries on the diffusion rates needed to create a measurable precipitation signature. It was found that in many cases a diffusion rate similar to those driven by naturally occurring waves was required, but in cases with a high number of electrons available to interact with the waves the diffusion rates could be orders of magnitude weaker and still produce a measurable amount of precipitation.Item Design, fabrication, and implementation of the energetic particle integrating space environment monitor instrument(Montana State University - Bozeman, College of Engineering, 2014) Gunderson, Adam Kristopher; Chairperson, Graduate Committee: Brock LaMeresThe ability to simultaneously monitor spatial and temporal variations in penetrating radiation above the atmosphere is important for understanding both the near Earth radiation environment and as input for developing more accurate space weather models. These models currently lack high resolution multi-point measurements to accurately portray the spatial and temporal variability of the radiation belts. To obtain data that may uncover the small-scale spatio-temporal variability of the areas around the planet known as the Van Allen Radiation Belts measurements must be made across a distributed array of satellites. The most recent decadal survey on solar and space physics states that the CubeSat platform is ideal for making these type of measurements [43]. The Energetic Particle Integrating Space Environment monitor instrument (EPISEM) will launch aboard eight CubeSat's as a part of the Edison Demonstration of Smallsat Networks (EDSN) mission. By being distributed across a geographically dispersed area, EPISEM will help fill the data gap by measuring the location and intensity of energetic charged particles simultaneously. This research describes the fabrication approach of the miniaturized radiation detection instrument aboard the EPISEM instrument and operational considerations unique to missions using many identical spacecraft and instruments. The EPISEM payload was specifically designed for CubeSats; leveraging heritage from the payload operating aboard Montana State University's Hiscock Radiation Belt Explorer (HRBE), launched in October 2011. The EDSN project is based at NASAs Ames Research Center, Moffett Field, California, and is funded by the Small Spacecraft Technology Program (SSTP) in NASAs Office of the Chief Technologist (OCT) at NASA Headquarters, Washington. The EDSN satellites are planned to fly late 2014 as secondary payloads on a DoD Operationally Responsive Space (ORS) mission that will launch into space from Kauai, Hawaii on a Super Strypi launch vehicle. The EPISEM payload was designed, built, tested, and delivered to NASA Ames by the Space Science and Engineering Laboratory at Montana State University.