Search NASA⌕ Search

SEARCH · Search NASA

Results for “electric thrusters”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 451 records · Page 25
All sourcesNASA NTRSDOE OSTI
NASA NTRS2006

NASA's 2004 In-Space Propulsion Refocus Studies for New Frontiers Class Missions

The New Frontiers (NF) program is designed to provide opportunities to fulfill the science objectives for top priority, medium class missions identified in the Decadal Solar System Exploration Survey. This paper assesses the applicability of the In-Space Propulsion s (ISP) Solar Electric Propulsion (SEP) technologies for representative NF class missions that include a Jupiter Polar Orbiter with Probes (JPOP), Comet Surface Sample Return (CSSR), and two different Titan missions. The SEP technologies evaluated include the 7-kW, 4,100-second NASA's Evolutionary Xenon Thruster (NEXT), the 3-kW, 2,700-second Hall thruster, and two different NASA Solar Electric Propulsion Technology Readiness (NSTAR) thrusters that are variants of the Deep Space 1 (DS1) thruster. One type of NSTAR, a 2.6-kW, 3,100-second thruster, will be the primary propulsion system for the DAWN mission that is scheduled to launch in 2006; the other is an "enhanced", higher power variant (3.8-kW, 4,100-second) and is so-called because it uses NEXT system components such as the NEXT power processing unit (PPU). The results show that SEP is applicable for the CSSR mission and a Titan Lander mission. In addition, NEXT has improved its applicability for these types of missions by modifying its thruster performance relative to its performance at the beginning of this study.

Witzberger, Kevin E.↗
NASA NTRS2020

Electric Propulsion for the Psyche Mission: Development Activities and Status

NASA’s Psyche mission will launch in 2022 and begin a 3.6-year cruise to the metallic asteroid Psyche, where it will examine this unique body. The baseline spacecraft design is a hybrid of JPL’s deep-space heritage subsystems with commercial partner Maxar’s electric propulsion, power, and structure subsystems. All primary propulsion will be done with SPT-140 thrusters, which will be the first use of Hall thrusters for a NASA mission. The electric propulsion subsystem and its implementation for the Psyche mission are described here. Major testing activities have included the successful completion of subsystem integrated testing with the design modifications required for Psyche, and a series of low-power thrust repeatability tests that were performed in support of navigation analyses. Thruster performance models have been further validated with new SPT-140 flight data, and new analyses of thruster swirl torque have been performed that result in much higher values than previously estimated. Analysis of recent Maxar flight data has also provided a new understanding of in-flight propellant usage uncertainties. Subsystem integration and test activities are now underway and the status and plans are discussed.

Johnson, Ian↗
NASA NTRS1976

Large-payload earth-orbit transportation with electric propulsion

Economical unmanned earth orbit transportation for large payloads is evaluated. The high exhaust velocity achievable with electric propulsion is attractive because it minimizes the propellant that must be carried to low earth orbit. Propellant transport is a principal cost item. Electric propulsion subsystems utilizing advanced ion thrusters are compared to magnetoplasmadynamic (MPD) thrust subsystems. For very large payloads, a large lift vehicle is needed to low earth orbit, and argon propellant is required for electric propulsion. Under these circumstances, the MPD thruster is shown to be desirable over the ion thruster for earth orbit transportation.

Stearns, J. W.↗
NASA NTRS2005

Results of a 2000 Hour Wear Tof the NEXIS Ion Engine

The Nuclear Electric Xenon Ion System (NEXIS) ion thruster was developed for potential outer planet robotic missions under NASA's Prometheus program. This engine was designed to operate at power levels ranging from 16 to over 20 kWe at specific impulses of 6000 to 7500 s for burn times of up to 10 years, satisfying the requirements of nuclear electric propulsion systems such as that on the proposed Prometheus 1 mission to explore the icy moons of Jupiter. State-of-the-art performance and life assessment tools were used to design the thruster. Following the successful performance validation of a Laboratory Model thruster, Development Model hardware was fabricated and subjected to vibration and wear testing. The results of a 2000-hour wear test are reported herein. Thruster performance achieved the target requirements and was steady for the duration of the test. Ion optics performance was similarly stable. Discharge loss increases of 6 eV/ion were observed in the first 500 hours of the test and were attributed to primary electron energy decreases due to cathode insert conditioning. Relatively high recycle rates were observed and were identified to be high-voltage-to-ground arcs in the back of the thruster caused by wire insulation outgassing and electron penetration through the plasma screen. Field emission of electrons between the accelerator and screen grids was observed and attributed to evolution of field emitter sites at accelerator grid aperture edges caused by ion bombardment. Preliminary modeling and analysis indicates that the NEXIS engine can meet mission performance requirements over the required lifetime. Finally, successful validation of the NEXIS design methodology, design tools, and technologies with the results of the wear test and companion performance and vibration tests presents significant applicability of the NEXIS development effort to missions of near-term as well as long-term interest for NASA.

Thruster performance↗
NASA NTRS1990

Experimental facilities for electric propulsion testing

Experimental facilities for electric propulsion testing at the University of Tennessee Space Institute, jointly operated by the Center for Advanced Space Propulsion, include a cryogenically cooled, computer-controlled, 9 ft diameter by 20 ft long vacuum chamber, capable of maintaining a baseline pressure of 10(exp -7) Torr, a 30 cm diameter ion thruster, and laser diagnostic and electrical diagnostic instrumentation. These facilities are described here in some detail, with emphasis on the measurement of ion thruster parameters such as neutral and ion densities, temperature, and velocity in the exhaust, as well as plasma potential and electron temperature.

Ruyten, Wilhelmus M.↗
NASA NTRS1977

A comparison of solar sail and ion drive trajectories for a Halley's comet rendezvous mission

According to the propulsion concept of solar sail spacecraft the thrust force is produced by the specular reflection of sunlight from a large, essentially flat, reflecting surface. The magnitude of this force is approximately 9 newtons for a perfectly reflecting sail with an area of 1 square kilometer oriented normal to the sunline at a distance of one astronomical unit from the sun. There exists a restriction in the types of orbit transfer trajectories which can be considered with this propulsion system. In the case of the second propulsion system being considered for the Halley's comet rendezvous mission, thrust is produced by the acceleration of ionized mercury atoms by an electric field. Power to the ion thrusters is supplied by lightweight solar arrays which can provide up to 100 kW of electrical power at a distance of 1 AU from the sun. Because of differing thrust constraints for the two propulsion systems, trajectories for a Halley's comet rendezvous mission are significantly different for the Ion Drive and Solar Sail spacecraft. Details concerning the trajectory characteristics are shown with the aid of a number of graphs.

Sauer, C. G., Jr.↗
NASA NTRS2001

Propulsion Instruments for Small Hall Thruster Integration

Planning and development are underway for the propulsion instrumentation necessary for the next AFRL electric propulsion flight project, which includes both a small Hall thruster and a micro-PPT. These instruments characterize the environment induced by the thruster and the associated data constitute part of a 'user's manual' for these thrusters. Several instruments probe the back-flow region of the thruster plume, and the data are intended for comparison with detailed numerical models in this region. Specifically, an ion probe is under development to determine the energy and species distributions, and a Langmuir probe will be employed to characterize the electron density and temperature. Other instruments directly measure the effects of thruster operation on spacecraft thermal control surfaces, optical surfaces, and solar arrays. Specifically, radiometric, photometric, and solar-cell-based sensors are under development. Prototype test data for most sensors should be available, together with details of the instrumentation subsystem and spacecraft interface.

ion probes↗
NASA NTRS2023

Facility Effects on the Ion Characteristics of A 12.5-Kw Hall Thruster

During a laser-induced fluorescence test of a 12.5-kW magnetically-shielded Hall thruster, ion characteristics in the discharge channel and near the poles were measured as the background pressure and electrical configuration were varied. The acceleration zone of the thruster moved upstream by 2% and 10% of the channel length when the background pressure was raised to 1.8 times and 7 times the lowest achievable pressure, respectively. Examination of the characteristics of the ions near the pole covers suggested that as the background pressure decreased the pole covers may be experiencing more erosion. When operating at a discharge voltage of 300 V, the acceleration zone was observed to be at the same location for all electrical configurations. When operating at a discharge voltage of 600V, the acceleration zone was observed to move 3% of the channel length upstream when the thruster body was floated instead of tied to the cathode or grounded to the facility. Characteristics of the ions bombarding the pole covers did not vary across the tested electrical configurations. This observation combined with thruster body voltage measurements suggested that varying the electrical configuration only affected the thruster body sheath voltage and did not affect the plasma potential beyond the sheath.

Electric propulsion↗
NASA NTRS1985

The Manned Maneuvering Unit - 'A nice flying machine'

The need for untethered maneuvers in extravehicular space was recognized early in the NASA manned spaceflight program, leading to experiments during the Gemini flights. The Space Shuttle crews are now equipped with a Manned Maneuvering Unit (MMU) which employs 24 gaseous nitrogen thrusters to furnish six-degree-of-freedom mobility and is fitted with fully redundant electronics, electrical, and propulsion subsystems. The MMU thrusters are operated with translational and rotational hand controllers at the ends of the MMU arms.

Bollendonk, W. W.↗
NASA NTRS1975

Determination of the extent of ion thruster efflux deposition on spacecraft surfaces from the SERT II flight thermal data

The flight thermal data from the SERT II satellite, the only electric propulsion mission with an extensive thruster operational history, is reviewed specifically to see if there is any evidence of contamination that could be attributed to the 5860 hours of mercury bombardment ion thruster operation. This evaluation shows that the only evidence of deposition occurred on the contamination experiment solar cells, which are located at the edge of the thruster exhaust beam. There is no evidence of any deposition of ion thruster efflux on any other surface of the vehicle.

Stevens, N. J.↗
NASA NTRS1978

Evolution of the 1-mlb mercury ion thruster subsystem

A general description and review of the auxiliary Electric Propulsion program, which led to the present 1-mlb (4.5 mN) thruster system, is presented. The developmental history, performance, and major lifetests of each component of the system are traced over the past 10 years. Major components include the 8-cm diameter ion thruster, the power processor, and the propellant reservoir and distribution system.

Kerslake, W. R.↗
NASA NTRS1971

An experimental investigation of a hollow cathode discharge

An experimental study of the effects of various modifications to the hollow cathode discharge region of a 20 cm electron bombardment ion thruster is presented. The introduction of electrical insulation between the main and cathode discharge regions is shown to have no significant effect on thruster performance. Adjustment of both the diameter and length of the cathode discharge region from the design condition are examined and the reduced sizes are shown to effect large improvements in propellant utilization when the thruster is operating at about 30% of the design thrust level. Performance improvements are shown to be less significant at higher thrust levels. The feasibility of using a high voltage tickler electrode to initiate the cathode-keeper discharge is considered and results obtained suggest this mode of startup is unsatisfactory.

Wilbur, P. J.↗
NASA NTRS1979

Nuclear electric power and propulsion system for earth orbital and solar system exploration applications

This paper discusses the design of a Nuclear Electric Propulsion (NEP) system, selection of thrusters and propellant. Outer planet exploration requirements are compared to earth orbital power requirements and a nuclear electric power system with a power level of 200 to 250 kWe is recommended. Current technology appears capable of accomplishing the early missions and growth potential exists for accomplishing more difficult later missions without significant changes in the basic system.

Phillips, W. M.↗
NASA NTRS1981

Electric propulsion - characteristics, applications, and status

A comparative review of the principles of ion thruster and chemical rocket operations is presented. The 30cm mercury ion thruster development and the specifications imposed on it by the Solar Electric propulsion System program are discussed. The 30cm thruster operating range, efficiency, wear out lifetime, and interface requirements are described.

Maloy, J. E.↗
NASA NTRS1981

Electric propulsion and its applications to space missions

Consideration is given the NASA, Air Force and European electric propulsion programs, the characteristics of primary electric propulsion systems, nuclear electric orbit transfer vehicles, and such topics in the fundamental processes of electrostatic thrusters as sputtering in mercury ion thrusters, the screen hole plasma sheath of an ion accelerator system, and the modelling of ion beam neutralization and nitrogen chemisorption. Also considered are electrostatic thruster components and systems, electromagnetic thrusters such as MPD and RIT systems, electric rail guns and mass drivers, power sources which include solar and nuclear alternatives, power conversion systems and their cooling apparatus, and the environmental interactions between spacecraft and their electric propulsion systems.

Finke, R. C.↗
NASA NTRS2013

Thrust Stand Measurements of a Conical Inductive Pulsed Plasma Thruster

Inductive Pulsed Plasma Thrusters (iPPT) spacecraft propulsion devices in which electrical energy is capacitively stored and then discharged through an inductive coil. The thruster is electrodeless, with a time-varying current in the coil interacting with a plasma covering the face of the coil to induce a plasma current Propellant is accelerated and expelled at a high exhaust velocity (O(10 -- 100 km/s)) by the Lorentz body force arising from the interaction of the magnetic field and the induced plasma current. While this class of thruster mitigates the life-limiting issues associated with electrode erosion, inductive pulsed plasma thrusters can suffer from both high pulse energy requirements imposed by the voltage demands of inductive propellant ionization, and low propellant utilization efficiencies. While this class of thruster mitigates the life-limiting issues associated with electrode erosion, inductive pulsed plasma thrusters can suffer from both high pulse energy requirements imposed by the voltage demands of inductive propellant ionization, and low propellant utilization efficiencies. A conical coil geometry may offer higher propellant utilization efficiency over that of a at inductive coil, however an increase in propellant utilization may be met with a decrease in axial electromagnetic acceleration, and in turn, a decrease in the total axially-directed kinetic energy imparted to the propellant.

Hallock, Ashley K.↗
NASA NTRS2004

An Overview of Electric Propulsion Activities at NASA

This paper provides an overview of NASA s activities in the area of electric propulsion with an emphasis on project directions, recent progress, and a view of future project directions. The goals of the electric propulsion programs are to develop key technologies to enable new and ambitious science missions and to transfer these technologies to industry. Activities include the development of gridded ion thruster technology, Hall thruster technology, pulsed plasma thruster technology, and very high power electric propulsion technology, as well as systems technology that supports practical implementation of these advanced concepts. The performance of clusters of ion and Hall thrusters is being revisited. Mission analyses, based on science requirements and preliminary mission specifications, guide the technology projects and introduce mission planners to new capabilities. Significant in-house activity, with strong industrial/academia participation via contracts and grants, is maintained to address these development efforts. NASA has initiated a program covering nuclear powered spacecraft that includes both reactor and radioisotope power sources. This has provided an impetus to investigate higher power and higher specific impulse thruster systems. NASA continues to work closely with both supplier and user communities to maximize the understanding and acceptance of new technology in a timely and cost-effective manner. NASA s electric propulsion efforts are closely coordinated with Department of Defense and other national programs to assure the most effective use of available resources. Several NASA Centers are actively involved in these electric propulsion activities, including, the Glenn Research Center, Jet Propulsion Laboratory, Johnson Space Center, and Marshall Space Flight Center.

Dunning, John W., Jr.↗