Engineering topics

Peter Peterson

Publications and source records attributed to Peter Peterson.

5 records

NASA NTRSDate not supplied

Extended Performance Characterization of the 12.5-kW Advanced Electric Propulsion System Engineering Test Unit Hall Thruster

This work presents a summary of the first detailed performance assessment of the Advanced Electric Propulsion System (AEPS) Engineering Test Unit 2 (ETU-2) thruster produced by Aerojet Rocketdyne at the throttle conditions most relevant for AEPS application on the Gateway Power and Propulsion Element (PPE). First, an assessment was performed of ETU-2 performance and backpressure sensitivity at the previously-tested throttle points of 300 V/6.25 kW, 400 V/8.33 kW, 500 V/10.42 kW, and 600 V/12.5 kW that confirmed ETU-2 and the test facility were both operating nominally and consistent with historical baselines. ETU-2 performance and stability were then assessed throughout the PPE throttle range of 2.6-12 kW and shown to be in-family with predictions based on the scaling of previous results. Taken together, these results will help inform application of AEPS on PPE as the AEPS design progresses towards its Critical Design Review.

HERMeS↗

NASA NTRSDate not supplied

Advanced Electric Propulsion System (AEPS) Enabling a Sustainable Return to the Lunar Surface through NASA Gateway

NASA continues to evolve a human exploration approach for beyond low-Earth orbit. The center of this approach is NASA’s Gateway that is envisioned to provide a maneuverable outpost in lunar orbit to extend human presence in deep space and expand on NASA exploration goals. The Gateway represents the initial step in NASA’s architecture for human cislunar operations, lunar surface access and missions to Mars. NASA announced at the May 2020 NASA Advisory Council’s Human Explorations and Operations Committee a new plan that calls for launching the first two elements of Gateway as a co-manifested mission in the late 2023 timeframe [2]. Launching the Power and Propulsion Element (PPE) and the Habitation and Logistics Outpost (HALO) together reduces mission risk, utilizes the PPE high-powered Electric Propulsion (EP) system to transport both elements to the lunar orbit, and reduces overall cost. NASA and Maxar Technologies have a commercial partnership to develop and demonstration a high-powered Solar Electric Propulsion (SEP) spacecraft [3, 4]. The PPE is baselined to include three 12.5-kW Advanced Electric Propulsion Systems (AEPS) and four 6-kW Hall thrusters, currently under development by Maxar, for a total beginning of life propulsion power of over 48-kW [5]. High-power solar electric propulsion is one of the key technologies that has been prioritized because of its significant exploration benefits, specifically, for missions beyond low Earth orbit. Spacecraft size and mass are currently dominated by onboard chemical propulsion systems and propellants that may constitute more than 50 percent of spacecraft mass. This impact can be substantially reduced through the utilization of SEP, due to its higher specific impulse and lower propellant load required to meet the equivalent mission delta-V. Studies performed for NASA’s HEOMD and Science Mission Directorate (SMD) have demonstrated that 40-kW-class SEP provides the necessary capabilities that would enable near term and future architectures, and science missions [6]. Accordingly, NASA has been developing a 12 kW Hall thruster electric propulsion thruster that can serve as the building block for a 40-kW-class SEP capability. The AEPS development, led by the NASA Glenn Research Center (GRC) and the Jet Propulsion Laboratory (JPL), began with the maturation of the high-power Hall thruster. The technology development work has transitioned to AR via a competitive procurement selection for the AEPS contract in May 2016. Management of the AEPS contract is being led by NASA GRC with funding from NASA’s Science Technology Mission Directorate (STMD) under the Technology Demonstration Missions (TDM) program. NASA continues to support the AEPS development leveraging in-house expertise, plasma modeling capability, and world-class test facilities.

AEPS↗

NASA NTRSDate not supplied

Extended Performance Characterization of the NASA HERMeS Hall Thruster

This work presents a summary of a detailed performance assessment of the Hall Effect Rocket with Magnetic Shielding (HERMeS) Technology Demonstration Unit 3 (TDU-3) thruster at the throttle conditions most relevant for the Gateway Power and Propulsion Element (PPE). First, an assessment was performed of TDU-3 performance and stability at the previously-tested throttle points of 300 V/6.25 kW, 400 V/8.33 kW, 500 V/10.42 kW, and 600 V/12.5 kW that confirmed TDU-3 was operating nominally and consistent with historical baselines. TDU-3 performance and stability were then assessed throughout the PPE throttle range of 2.6-12 kW and shown to mirror the characteristics observed at the previously tested conditions. Finally, a statistical estimate for the thrust specification at the expanded set of throttle conditions was computed and found to yield similar tolerance ranges to those calculated for the heritage conditions. Taken together, these results provide strong evidence that the demonstrated performance characteristics of the HERMeS design are preserved at the expanded set of throttle conditions relevant to application on PPE.

HERMeS↗

NASA NTRSDate not supplied

Development Of 12 Kw Hall Thrusters for Nasa Lunar Gateway Power And Propulsion Element

NASA is embarking on a new and exciting era of human exploration to the Moon and its vicinity. As part of the Artemis program, NASA is developing the lunar Gateway, an orbiting platform in Near Rectilinear Halo Orbit (NRHO) about the Moon. The first two elements of the Gateway will be launched in 2024 and will be transferred from a high Earth orbit to the NRHO via the use of Solar Electric Propulsion (SEP). The SEP system is located on the Power and Propulsion Element (PPE) which will provide up to 60 kW of power. Aerojet Rocketdyne is developing the 12 kW flight Hall thrusters to be used for transferring the PPE and the Habitat and Logistics Outpost (HALO) module to NRHO. Work is continuing on the development testing, and these results will be described in the paper. The project has also recently completed its critical design review and is transitioning to the fabrication of the three flight thrusters. The 12 kW Hall thrusters are being developed under the NASA Advanced Electric Propulsion System (AEPS) program. As part of the AEPS program, AR built two Engineering Test Unit (ETU) Hall thrusters based on the NASA HERMeS engine and conducted a series of tests to validate the design. One series of tests focused on environments and functional testing, while the other series was mainly focused on long duration test blocks. Results from these tests were used to compare with NASA data from the HERMeS thruster. The comparison of the test results showed no change to the critical performance and lifetime parameters, which enabled the next phase of the program to proceed. Currently testing is continuing on the Engineering Development Units (EDU) as part of the flight qualification activities. The successful completion of the CDR serves as the starting point for the flight thruster fabrication, which is now underway to support the launch of the Gateway modules in 2024. The development and qualification of the AEPS 12 kW Hall thrusters is proceeding well. As the program completes CDR and transitions into flight builds of the three 12 kW Hall thrusters that will be used to transfer the combined PPE and HALO stack to the NRHO, the results of the development testing are reviewed in this presentation, and a status of the program and future plans is provided. The launch of the two Gateway modules and the transfer of this large payload to cislunar orbit will mark a significant milestone in electric propulsion, as it will demonstrate the ability of SEP to transfer very large payloads over great distances. This establishes the precedent that could lead to cargo transfers from the Earth to the Moon or even to Mars using SEP.

Hall thrusters↗

NASA NTRSDate not supplied

PPE Electric Propulsion Advancing to CDR: 12kW String

String level testing is a vital part of electric propulsion development. With the Power and Propulsion Element (PPE) spacecraft flying two new models of Hall Thrusters, this work is even more critical. PPE will have both 6kW and 12kW thruster strings onboard, all powered by Maxar power processing units (PPU). Both strings have recently undergone end-to-end string level hot fire testing to verify the ability of all components to work together. This entails operating the thruster with the Xenon Flow Controller (XFC) and PPUs under both nominal and off-nominal conditions to stress the system and determine weak points. Such testing has long been a standard Maxar practice since our first 1.5kW electric propulsion system in 2004. This paper will focus on Phase 1 of the 12kW testing recently completed at NASA Glenn. The primary conclusion of the test effort was that the 12kW string operated nominally and that the PPU and XFC could operate the thruster within specifications.

Electric propulsion↗