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Showing papers on "Arcjet rocket published in 2002"


Journal ArticleDOI
TL;DR: The U.S. Air Force Research Laboratory's Electric Propulsion Space Experiment was launched and successfully operated on the Advanced Research and Global Observation Satellite, demonstrating the compatibility and readiness of high-power electric propulsion as mentioned in this paper.
Abstract: The U.S. Air Force Research Laboratory’ s Electric Propulsion Space Experiment was launched and successfully operated on the Advanced Research and Global Observation Satellite, demonstrating the compatibility and readiness of high-power electric propulsion. This e ight was the culmination of an Air Force technology program to demonstrate the applicability of high-power electric propulsion for satellite applications. A brief history of the program is presented, followed by a description of the e ight operations, which successfully demonstrated the critical system components, the arcjet, power processor, and propellant feed system, verifying the interoperability of high-power electric propulsion with satellite operations. The two anomalies experienced during on-orbit operations, and their proposed causes, are also described.

14 citations


Proceedings ArticleDOI
14 Jan 2002

13 citations


Proceedings ArticleDOI
20 May 2002
TL;DR: In this paper, the number density distribution of metastable atomic oxygen was obtained from the measured absorption line profile at 777.19 nm in argon-oxygen plumes generated by arcjet type arc-heaters.
Abstract: Laser absorption spectroscopy has been applied to the measurement of arc-heater plumes. Number density distribution of metastable atomic oxygen was obtained from the measured absorption line profile at 777.19 nm in argon-oxygen plumes generated by arcjet type arc-heaters. As a result, oxygen is found localized off axis at the nozzle exit, and diffusing from outside to the axis in the plume. Moreover, CFD simulation was conducted to investigate the mixing process of oxygen in the arc-heater. The result indicates that the degree of oxygen dissociation in the plume would be at the level of 0.01%.

11 citations


Journal ArticleDOI
TL;DR: The mean values of thrust, specie c impulse, and thrust efe ciency are estimated to be 1.93 § 0.06 N, 786.2 § 43.0s, and 0.267 § 1.021,respectively as mentioned in this paper.
Abstract: During the Electric Propulsion Space Experiment mission, eight e rings of the 26-kW ammonia arcjet were performed. Data from onboard systems,including an accelerometerandglobal positioning system unit, are used to determine thruster performance. In addition, ground-based tracking is used to determine velocity change during these e rings. The mean values of thrust, specie c impulse, and thrust efe ciency are estimated to be 1.93 § 0.06 N, 786.2§ 43.0s,and 0.267 § 0.021,respectively.Thismeasuredperformanceislowerthanexpectedbasedon ground test.Themostlikelycauseofthisdiscrepancyiserrorinonboardmeasurementofdischargepowerduetoa6%drift inthepowerprocessing unitcurrent shunt.Atthecorrected power, performancefallswithintheexpectedenvelope.

10 citations


Journal ArticleDOI
TL;DR: The Electric Propulsion Space Experiment (ESEX) flew in 1999 on the Air Force Space Test Program Advanced Research and Global Observation Satellite (ATGOSAT) as discussed by the authors to address potential in-space operational issues associated with the use of high-power electric propulsion.
Abstract: The Electric Propulsion Space Experiment (ESEX) flew in 1999 on the Air Force Space Test Program Advanced Research and Global Observation Satellite. ESEX was initiated to address potential in-space operational issues associated with the use of high-power electric propulsion. Potential issues included plume deposition, electromagnetic interference, and thermal radiation. Because of physical constraints of even the largest test facilities, that is, vacuum chamber size, these phenomena are best measured in space. The propulsion component for the ESEX demonstration, a 26-kW ammonia arcjet propulsion subsystem, including thruster, power processing, and propellant feed, was developed and flight qualified on the Air Force Research Laboratory'Arcjet Advanced Technology Transition Demonstration program. Each of the propulsion system elements, the principal design challenges, and the program of risk reduction and qualification testing that provided preflight verification of the arcjet propulsion subsystem are described.

10 citations


Journal ArticleDOI
TL;DR: The U.S. Air Force Research Laboratory's Electric Propulsion Space Experiment (ESEX) was launched and operated in early 1999 to demonstrate the compatibility and readiness of a 30-kW class ammonia arcjet for satellite propulsion applications as mentioned in this paper.
Abstract: The U.S. Air Force Research Laboratory's Electric Propulsion Space Experiment (ESEX) was launched and operated in early 1999 to demonstrate the compatibility and readiness of a 30-kW class ammonia arcjet for satellite propulsion applications. As part of this flight, an array of onboard contamination sensors was used to assess the effect of the arcjet and other environments on the spacecraft. The sensors consisted of microbalances to measure material deposition, radiometers to assess material degradation due to thermal radiation or contamination, and solar cell segments to investigate solar array degradation. Over eight firings of the ESEX arcjet, and 33 min, 26 s operating time, the radiometer near the thruster, viewing the arcjet plume and body, experiences a change in the thermal properties of its coating from the firings. Radiometers with no view of the arcjet, or a view of only the plume, show no change. In general, degradation effects are observed only on sensors near the thruster exhaust nozzle, a location unlikely to be used in an operational high-power electric propulsion system. No degradation effects are observed in the backplane of the thruster. For future programs, although engineering measures may be needed for spacecraft equipment in the immediate vicinity of the thruster body, the arcjet environment is generally benign.

8 citations


Journal ArticleDOI
TL;DR: In this article, two kinds of magnetohydrodynamic (MHD) instabilities excited in a current-carrying cylindrical plasma that was produced by a magneto-plasma-dynamic arcjet were observed.
Abstract: We have observed two kinds of magnetohydrodynamic (MHD) instabilities excited in a current-carrying cylindrical plasma that was produced by a magneto-plasma-dynamic (MPD) arcjet. The “net current” in the plasma excites the instability with the azimuthal mode number m =1, which is deduced to be a kink mode from MHD theory. On the other hand, the m =0 instability is excited by the “total current” flowing to the cathode, and this mode was found to be responsible for the modulation of electron temperature. They are converted respectively to m =1 compressional Alfven wave and m =0 global Alfven eigenmode, propagating along the axial magnetic field in the current-free region.

8 citations


Journal ArticleDOI
TL;DR: The Electric Propulsion Space Experiment (ESEX) was launched and operated in early 1999 to demonstrate the compatibility and readiness of a 30-kW class ammonia arcjet for satellite propulsion applications.
Abstract: The Electric Propulsion Space Experiment (ESEX) was launched and operated in early 1999 to demonstrate the compatibility and readiness of a 30-kW class ammonia arcjet for satellite propulsion applications. As part of thisflight, an array of onboard contamination sensors assessed the effects of the arcjet on the spacecraft. The sensors consisted of microbalances to measure material deposition, radiometers to assess material degradation due to thermal radiation, and solar cell segments to investigate solar array degradation. During firings, the solar cell segments showed decreasing open-circuit voltages, probably due to additional electrical load imposed by currents through the plume plasma. Over eight firings of the ESEX arcjet, and 33-min, 44-s operating time, the solar cells exhibited a 3% decrease in short-circuit current, attributable to decreased solar transmission of the cover glass. The spacecraft's main solar arrays, however, exhibited no degradation in performance. Contamination affected only the solar cell sensor segments placed near the thruster exhaust nozzle. In the backplane of the thruster, where the main arrays are located, no deleterious effects occurred, indicating that although engineering measures may be required for equipment in the immediate vicinity of the thruster, the arcjet environment is generally benign.

8 citations


Journal ArticleDOI
TL;DR: In this paper, all the types of electric propulsions are studied as the high ΔV mission enablers and in this report these accomplishments and future prospects are introduced, and they are divided into three major groups according to their plasma acceleration principles, electromagnetic, electrostatic and electrothermal devices.

7 citations


Journal ArticleDOI
TL;DR: In this article, the ESEX 26kW arcjet was used for eight flight firings in March and April 1999, and optical observations from onboard and ground-based sensors were obtained.
Abstract: During the course of eight flight firings of the ESEX 26-kW arcjet in March and April 1999, optical observations from onboard and ground-based sensors were obtained. Images of the thruster plume at 656 nm confirm expectations that the plume luminescence in the space environment is more compact than that from a thruster operated in the laboratory at higher background pressure. Observations using a ground-based telescope reveal blackbody and line emission spectrum over the range 325-675 nm. The spectral features are consistent with ground tests. Line ratios observed in flight show a moderately higher degree of excitation than ground tests, which is consistent both with the higher specific power and the less collisional plume expansion of the flight test compared to ground tests.

7 citations



Journal ArticleDOI
TL;DR: In this paper, a computer model has been set up for simulation of the flow and temperature field, and the radial distribution of atomic hydrogen and active carbonaceous species over a large area substrate surface for a new type dc arc plasma torch with rotating arc roots and operating at gas recycling mode.
Abstract: A computer model have been set up for simulation of the flow and temperature field, and the radial distribution of atomic hydrogen and active carbonaceous species over a large area substrate surface for a new type dc arc plasma torch with rotating arc roots and operating at gas recycling mode A gas recycling radio of 90% was assumed. In numerical calculation of plasma chemistry, the Thermal-Calc program and a powerful thermodynamic database were employed. Numerical calculations to the computer model were performed using boundary conditions close to the experimental setup for large area diamond films deposition. The results showed that the flow and temperature field over substrate surface of Φ60-100mm were smooth and uniform. Calculations were also made with plasma of the same geometry but no arc roots rotation. It was clearly demonstrated that the design of rotating arc roots was advantageous for high quality uniform deposition of large area diamond films. Theoretical predictions on growth rate and film quality as well as their radial uniformity, and the influence of process parameters on large area diamond deposition were discussed in detail based on the spatial distribution of atomic hydrogen and the carbonaceous species in the plasma over the substrate surface obtained from thermodynamic calculations of plasma chemistry, and were compared with experimental observations.

Journal ArticleDOI
TL;DR: The Electric Propulsion Space Experiment (ESEX) was launched and operated in early 1999 to demonstrate the compatibility and readiness of a 30-kW class ammonia arcjet for satellite propulsion applications.
Abstract: The Electric Propulsion Space Experiment (ESEX) was launched and operated in early 1999 to demonstrate the compatibility and readiness of a 30-kW class ammonia arcjet for satellite propulsion applications. As part of the onboard sensor array, thermoelectric quartz crystal microbalances were used to measure material deposition at selected locations on the spacecraft surface. The sensors were held at a temperature that would allow them to condense metallic materials eroded from the electrodes, but that are insensitive to possible deposition of the propellant gas. The ESEX arcjet was fired eight times, constituting 33 min and 26 s of operating time. No material deposition was observed that could be attributed to nominal the arcjet firings, although during the first firing, significant deposition was observed near the arcjet nozzle. This deposition is attributed to contaminants within the arcjet body, collected during handling and storage, which were ejected during the first firing. For future programs, although engineering measures may be needed to protect spacecraft equipment in the immediate vicinity of the thruster body, the arcjet environment causes negligible deposition of electrode material.

Journal ArticleDOI
TL;DR: In this paper, a series of qualitative observations consistently indicated the benign nature of arcjet operation on normal spacecraft events, for example, commands uplinked without abnormal rejection rate and telemetry downlinked successfully during arcjet operations.
Abstract: Tests designed to observe the electromagnetic compatibility of the Electric Propulsion Space Experiment 26-kW ammonia arcjet on normal spacecraft communications and operations showed no conclusive adverse effect. Two onboard antennas sensitive to the 2-, 4-, 8-, and 12-GHz frequencies detected no increase in signal amplitude clearly identifiable with arcjet operation. Analysis of the bit-error-rate test data revealed no obvious correlation between arcjet operation and the observed increases in bit-error rate. Finally, a series of qualitative observations consistently indicated the benign nature of arcjet operation on normal spacecraft events. For example, commands uplinked without abnormal rejection rate and telemetry downlinked successfully during arcjet operation.

Journal ArticleDOI
TL;DR: The U.S. Air Force Research Laboratory's Electric Propulsion Space Experiment was launched and successfully operated, demonstrating the compatibility and readiness of a 26kW ammonia arcjet subsystem for satellite applications as mentioned in this paper.
Abstract: The U.S. Air Force Research Laboratory's Electric Propulsion Space Experiment was launched and successfully operated, demonstrating the compatibility and readiness of a 26-kW ammonia arcjet subsystem for satellite applications. The Electric Propulsion Space Experiment is one of nine experiments on the U.S. Air Force's Advanced Research and Global Observation Satellite. Data were acquired to characterize the thruster in four different areas: electromagnetic interactions, contamination effects, optical properties of the plume, and thruster system performance. The results demonstrated that the critical system components including the arcjet, power processor, and propellant system operated well and verified the interoperability of high-power electric propulsion with generic satellite operations.

Proceedings ArticleDOI
07 Jul 2002
TL;DR: The microwave discharge ion engine system on MUSES-C and the DC arcjet on DRTS are now under preparation for space flight in this year and the Kaufman type ion engine on ETS-VIII will be launched soon.
Abstract: The microwave discharge ion engine system on MUSES-C and the DC arcjet on DRTS are now under preparation for space flight in this year. The Kaufman type ion engine on ETS-VIII will be launched soon. Besides these well-developed system some joint ventures with universities and companies invest energetic R & D efforts to the large ion engines, the Hall thruster with high performance, the space applicable PPT and the low power DC arcjet. The academic activities are still brisk in the field of electric propulsion and related topics in Japan. 1. INTRODACTION Many universities and institutes in Japan have investigated the physics of electric propulsion and the related phenomena since 1970’s because they are very attractive topics. Based on the academic research some kinds of electric propulsion system and the integration technology were developed. Some flight demonstrations supplied a lot of information and experiences to Japanese industry and academic community. Passing through the R & D era the electric propulsion is applied to the main system in the bus technology. The MUSES-C and DRTS spacecraft will be launched accompanying with electric propulsion in this year. The flight of ETSVIII is close at hand. In order to support wide variety of space application including huge system and micro probes a lot of engineering effort is invested energetically by joint ventures with universities and companies. The academic research is still active in the field of electric propulsion. This paper will report the recent activities related on the electric propulsion of Japan in the following three sections.

Journal ArticleDOI
TL;DR: In this article, a 30kW class ammonia arcjet flight experiment was designed, built, qualified, and operated in space as part of the 30-kW Class Arcjet Advanced Technology Transition Demonstration Program.
Abstract: Electric arcjet propulsion systems provide an attractive option for enhancing spacecraft payload mass, increasing on-orbit lifetimes, and reducing launch costs as long as the mission can accommodate the low-thrust levels inherent to electric propulsion. To demonstrate this technology, a 30-kW class ammonia arcjet flight experiment was designed, built, qualified, and operated in space as part of the 30-kW Class Arcjet Advanced Technology Transition Demonstration Program. The engineering qualification and spacecraft integration of the propulsion system are summarized.

01 Feb 2002
TL;DR: In this article, a flame diagnostic Multiphoton Laser Induced Fluorescence (LIF) was applied to the excited-state plasma environment to investigate concentration levels of atomic ground-state hydrogen.
Abstract: : Pulsed Plasma Thrusters (PPT) have been the major technology under investigation for the Small Satellite Electric Propulsion Thruster Research program Arcjet technology is also under investigation with Electric Propulsion Space Experiment Optical Signature experiments underway and Multiphoton Laser Induced Fluorescence Measurements of Ground State Atomic Hydrogen have been performed in an arcjet plume At present PPTs are being tested in the laboratory environment with investigations under way to determine exact inefficiency mechanisms that can be corrected This work has already identified previously unknown physical behavior in the PPT The Electric Propulsion Space Experiment is a flight demonstration of a 30 kW ammonia arcjet propulsion system Optical measurements of the arcjet plume were performed using on-board optical equipment ground observatories and other space platforms Low power arcjet technology provided definitive work on atomic species plume concentrations in low power hydrogen arcjet plumes This work applied a flame diagnostic Multiphoton Laser Induced Fluorescence to the excited-state plasma environment to investigate concentration levels of atomic ground-state hydrogen


01 Jan 2002
TL;DR: In this paper, a high density and high speed flowing helium-plasma is produced quasi-steadily (1 ms) by use of a magnetoplasma-dynamic arcjet (MPDA) in various external magnetic field configurations.
Abstract: A high-density and high-speed flowing helium-plasma is produced quasi-steadily (1 ms) by use of a magneto-plasma-dynamic arcjet (MPDA) in various external magnetic field configurations. In a uniform magnetic field configuration, an ion acoustic Mach number Mi Of the plasma flow is limited to be nearly unity. In a divergent magnetic nozzle configuration, on the other hand, the Mach number increases up to almost 3. The Mach number increases in proportion to the gradient of the magnetic field. Spatial variations of Mj are well predicted by an isentropic model of compressible flow. The Mach number decreases in the downstream region due to charge-exchange collisional processes that are caused by a limited pumping capability of surface-recombined neutral gases.



Journal ArticleDOI
TL;DR: In this paper, the number density distributions of atomic metastable oxygen were obtained from the measured absorption line profile at 777.19 nm in argon-oxygen plumes generated by arcjet type arc-heaters.
Abstract: Absorption spectroscopy has been applied to the measurement of the arc-heater plumes. Number density distributions of atomic metastable oxygen were obtained from the measured absorption line profile at 777.19 nm in argon-oxygen plumes generated by arcjet type arc-heaters. As a result, it was found that the oxygen is localized off axis at the nozzle exit, and diffuses from outside toward the centerline in the plume. Moreover, numerical simulation was conducted to investigate the diffusion process of the oxygen in the arc-heater. The result indicates that the maximum degree of oxygen dissociation would be at the level of 0.01%.

Journal ArticleDOI
TL;DR: In this article, the nitrogen in polycrystalline diamond films prepared using the direct current arcjet plasma process has been studied using scanning electron microscopy, X-ray diffraction and electron spin resonance (ESR).

Proceedings ArticleDOI
07 Jul 2002
TL;DR: In this article, the authors investigated vehicle sizing and performance requirements for a free-flying 500-kW solar array in orbital formation with a power-consuming host vehicle, which required independent propulsion for two functions: formation keeping with the host and attitude control for sun-pointing maneuvers.
Abstract: This paper investigates vehicle sizing and performance requirements for a free-flying 500-kW solar array in orbital formation with a power-consuming host vehicle. To meet these requirements, the sail vehicle required independent propulsion for two functions: formation-keeping with the host and attitude control for sun-pointing maneuvers. The equations of motion were developed assuming a rigid vehicle subject to gravity, aerodynamic drag, and solar pressure. A numerical optimization tool was developed to select the optimum orbital trajectory for seven canonical electric propulsion technologies: Teflon pulsed plasma thruster, hydrazine resistojet, hydrazine arcjet, ammonia arcjet, xenon Hall thruster, and xenon ion thruster. Subject to orbital and formation-flying constraints, the thrust amplitudes, firing sequences where developed to minimize the total vehicle mass was minimized. The best performance (lowest vehicle total mass) was found using a xenon ion propulsion system resulting in a 1,693 kg vehicle. The worst performance, (highest vehicle mass) was found using the N2H4 Resistojet resulting in a 2,191 kg vehicle. In addition to providing electric propulsion mission feasibility information, it was found that the optimal orbits, invariant of the thruster technology, sacrificed sun-pointing time for external force reduction.

Journal ArticleDOI
TL;DR: In this paper, a preliminary life test of a low-power DC arcjet anode was conducted using a 500-W-class laboratory-model arcjet, and micrograph analyses showed different degradation features for the two anodes: for the conventional tungsten anode, grains were severely embrittled in the recrystalization processes after the thruster operation accompanied by many cracks or even drops out of grains.
Abstract: A preliminary life test of a low-power DC arcjet anode was conducted using a 500-W-class laboratory-model arcjet. After a continuous operation of 90-h, we compared the degradation of two types of anodes: one is a conventional pure tungsten anode, which is made of multiple fine grains of several tens of micrometer in size; another is a tungsten anode made of only four coarse grains. Both materials showed nearly the same amount of degradation from the viewpoint of so-called a constrictor closure phenomenon, in which the radius of the constrictor decreases during the continuous operation. However, micrograph analyses showed different degradation features for the two anodes: for the conventional tungsten anode, grains were severely embrittled in the recrystalization processes after the thruster operation accompanied by many cracks or even drops out of grains; in contrast, the anode made of four coarse grains showed a few cracks only along the grain boundaries, and its thrust performance was unchanged before and after the 90-h test. Hence there is a possibility to suppress the grain embrittlement by completely removing these grain boundaries from the tungsten anode by making the anode from one huge grain.

01 Jan 2002
TL;DR: In this paper, the authors investigated vehicle sizing and performance requirements for a free-ying 500-kW solar array in orbital formation with a power consuming host vehicle to meet these requirements, the sail vehicle required independent propulsion for two functions: formation keeping with the host and attitude control for sun-pointing maneuvers.
Abstract: This paper investigates vehicle sizing and performance requirements for a free-ying 500-kW solar array in orbital formation with a power-consuming host vehicle To meet these requirements, the sail vehicle required independent propulsion for two functions: formation-keeping with the host and attitude control for sun-pointing maneuvers The equations of motion were developed assuming a rigid vehicle subject to gravity, aerodynamic drag, and solar pressure A numerical optimization tool was developed to select the optimum orbital trajectory for seven canonical electric propulsion technologies: Teon pulsed plasma thruster, hydrazine resistojet, hydrazine arcjet, ammonia arcjet, xenon Hall thruster, and xenon ion thruster Subject to orbital and formation-ying constraints, the thrust amplitudes, ring sequences where developed to minimize the total vehicle mass was minimized The best performance (lowest vehicle total mass) was found using a xenon ion propulsion system resulting in a 1,693 kg vehicle The worst performance, (highest vehicle mass) was found using the N2H4 Resistojet resulting in a 2,191 kg vehicle In addition to providing electric propulsion mission feasibility information, it was found that the optimal orbits, invariant of the thruster technology, sacriced sun-pointing time for external force reduction