{"project":{"acronym":"","projectId":91462,"title":"Characterization of a Green Solid Electric Propellant for Electric Propulsion","primaryTaxonomyNodes":[{"taxonomyNodeId":10537,"taxonomyRootId":8816,"parentNodeId":10533,"level":3,"code":"TX01.1.4","title":"Solids","definition":"This area covers propulsion systems that operate with solid propellants, where the propellants are pre-mixed oxidizers and fuels.","exampleTechnologies":"Polybutadiene Acrylic Acid Acrylonitrile Prepolymer (PBAN), Hydroxyl Terminated Poly Butadiene (HTPB)","hasChildren":false,"hasInteriorContent":true}],"startTrl":2,"currentTrl":3,"endTrl":3,"benefits":"
The development of Solid Electric Propellants is an emerging topic of research with major implications in the field of space propulsion from the micro to macro scale. Solid Electric Propellants offer new and exciting capabilities in the field of solid rocket propulsion, such as throttling and extinguishment/re-ignition. Additionally, some of these propellants, like the type being developed by the small business Digital Solid State Propulsion (DSSP) in Nevada, are insensitive to ignition by spark, impact or open flame, making them much safer to transport and handle. Further, this higher performance electric propellant (HIPEP) is easily manufactured and uses \"green\" ingredients.
","description":"The development of Solid Electric Propellants is an emerging topic of research with major implications in the field of space propulsion from the micro to macro scale. Solid Electric Propellants offer new and exciting capabilities in the field of solid rocket propulsion, such as throttling and extinguishment/re-ignition. Additionally, some of these propellants, like the type being developed by the small business Digital Solid State Propulsion (DSSP) in Nevada, are insensitive to ignition by spark, impact or open flame, making them much safer to transport and handle. Further, this higher performance electric propellant (HIPEP) is easily manufactured and uses \"green\" ingredients. Recently, DSSP has developed a microthruster utilizing this green Solid Electric Propellant and operates in a mode very similar to a traditional type of electric propulsion, the coaxial Pulsed Plasma Thruster (PPT). These microthrusters are extremely well suited to widespread small spacecraft applications due to a very small size (1/8\" diameter, 1\" length), low power requirements (nominal 2-5 W capacitor charging cycle) and ease of handling and integration. While these microthrusters are quite promising as an on-board propulsion solution to one of the major challenges in small spacecraft applications, mobility, it is not well characterized how these microthrusters compare to the performance of a traditional PPT. More specifically, the performance and thermochemical contributions of the HIPEP in comparison to the traditional and well studied PPT propellant, Teflon, are subject to investigation. The main objective of this project is to characterize the thermochemical behavior and performance of the HIPEP propellant and provide insightful comparisons in its role as a PPT propellant to that of Teflon. Specific objectives to reach that end include: 1.) conducting plasma plume diagnostic studies of PPT operation for the HIPEP and Teflon thrusters, 2.) fully characterizing the performance of both thrusters and comparison to traditional PPT performance data and 3.) using acquired data to model the magneto-hydro-dynamic (MHD) environment in addition to the thermochemical processes that are present in the operation of the HIPEP PPT. Plasma plume diagnostic methods for PPT's are well outlined by literature in the field of electric propulsion, and are easily adapted to the HIPEP microthruster. Plume characterization work on the HIPEP thruster has already begun at the Missouri University of Science and Technology as part of the student applicant's doctoral research program, and this type of work could be enhanced by further testing at a NASA center such as the MSFC (MSFC) and/or NASA GRC (GRC). Performance characterization of a HIPEP thruster and Teflon thruster will build off previous research from DSSP and the electric propulsion community, respectively, that would serve to jump-start, outline, and guide the approach for this project. Performance characterization would also greatly benefit from testing at MSFC and/or GRC due to the expertise of researchers and quality of available hardware. MHD modeling will be conducted using established simulation environments such as the MACH2 software and traditional thermochemical equation of state reactive material modeling methods using the Sesame library to help characterize and understand the contributions of thermochemical processes and the chemical makeup of HIPEP to the performance of the microthruster.
","startYear":2015,"startMonth":8,"endYear":2019,"endMonth":7,"statusDescription":"Completed","principalInvestigators":[{"contactId":179488,"canUserEdit":false,"firstName":"Henry","lastName":"Pernicka","fullName":"Henry J Pernicka","fullNameInverted":"Pernicka, Henry J","middleInitial":"J","primaryEmail":"pernicka@mst.edu","publicEmail":false,"nacontact":false}],"programDirectors":[{"contactId":84634,"canUserEdit":false,"firstName":"Claudia","lastName":"Meyer","fullName":"Claudia M Meyer","fullNameInverted":"Meyer, Claudia M","middleInitial":"M","primaryEmail":"claudia.m.meyer@nasa.gov","publicEmail":true,"nacontact":false}],"programExecutives":[{"contactId":84634,"canUserEdit":false,"firstName":"Claudia","lastName":"Meyer","fullName":"Claudia M Meyer","fullNameInverted":"Meyer, Claudia M","middleInitial":"M","primaryEmail":"claudia.m.meyer@nasa.gov","publicEmail":true,"nacontact":false}],"programManagers":[{"contactId":183514,"canUserEdit":false,"firstName":"Hung","lastName":"Nguyen","fullName":"Hung D Nguyen","fullNameInverted":"Nguyen, Hung D","middleInitial":"D","primaryEmail":"hung.d.nguyen@nasa.gov","publicEmail":true,"nacontact":false}],"projectManagers":[{"contactId":280557,"canUserEdit":false,"firstName":"Kurt","lastName":"Polzin","fullName":"Kurt A Polzin","fullNameInverted":"Polzin, Kurt A","middleInitial":"A","primaryEmail":"kurt.a.polzin@nasa.gov","publicEmail":true,"nacontact":false}],"coInvestigators":[{"contactId":321632,"canUserEdit":false,"firstName":"Matthew","lastName":"Glascock","fullName":"Matthew Glascock","fullNameInverted":"Glascock, Matthew","primaryEmail":"msgdm3@mst.edu","publicEmail":false,"nacontact":false}],"website":"https://www.nasa.gov/strg#.VQb6T0jJzyE","libraryItems":[],"transitions":[{"transitionId":75809,"projectId":91462,"transitionDate":"2019-07-01","path":"Closed Out","details":"Electric solid propellants are advanced solid chemical rocket propellants that can be controlled (ignited, throttled and extinguished) through the application and removal of an electric current. These propellants are also being considered for use in ablative pulsed plasma thruster and multimode systems. In this work, the behavior and performance of a novel green electric solid propellant operating in an electrothermal ablation-fed pulsed plasma thruster was investigated. Using an inverted pendulum micro-Newton thrust stand, the impulse bit and specific impulse of the device using the electric solid propellant were measured for short-duration and long-duration runs to end-of-life, at energy levels of 5, 10, 15 and 20 J. Also, the device was operated using the current state-of-the-art ablation-fed pulsed plasma thruster propellant, polytetrafluoroethylene or PTFE. Impulse bit measurements for PTFE indicate 100 µN-s at an initial energy level of 5 J, which increases linearly by ~30 µN-s/J with initial energy. Measurements of the impulse bit for the electric solid propellant are on average lower than PTFE by about 5%. Further, it is shown that absorbed water in the hygroscopic electric solid propellant evaporates rapidly during early discharges of the device. This mass loss artificially decreased specific impulse relative to traditional propellant. Removing this evaporated mass from the ablation mass loss measurements, the corrected specific impulse of the propellant is 300 s compared to 450 s for PTFE. The electric solid propellant shows some promise for future multimode application but is currently limited in electric propulsion application by poor ablation efficiency and the absorption of atmospheric water.","infoText":"Closed out","infoTextExtra":"","dateText":"July 2019"}],"responsibleMd":{"acronym":"STMD","canUserEdit":false,"city":"","external":false,"linkCount":0,"organizationId":4875,"organizationName":"Space Technology Mission Directorate","organizationType":"NASA_Mission_Directorate","naorganization":false,"organizationTypePretty":"NASA Mission Directorate"},"program":{"acronym":"STRG","active":true,"description":"\tThe Space Technology Research Grants Program will accelerate the development of "push" technologies to support the future space science and exploration needs of NASA, other government agencies and the commercial space sector. Innovative efforts with high risk and high payoff will be encouraged. The program is composed of two competitively awarded components.
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