Ion flux, energy, and charge-state measurements for the BPT-4000 Hall thruster

Pollard, James E.; Diamant, Kevin D.; Khayms, Vadim; Werthman, Lance; King, D. Q.; Grys, Kristi de

doi:10.2514/6.2001-3351

Cited by 24 publications

(21 citation statements)

References 1 publication

Supporting

Mentioning

Contrasting

Order By: Relevance

“…29,30 The presence of slow charge-exchange ions in the plume and multi-charged ions from the thruster 30 could still lead to the overestimation of the plasma density. However, a reduction of ~ 70% of the total ion flux is required for the experimental frequency to match the theoretical SCS limit at, for instance, V d = 550V.…”

Section: B Determination Of Plasma Parametersmentioning

confidence: 99%

Space charge saturated sheath regime and electron temperature saturation in Hall thrusters

et al. 2005

View full text Add to dashboard Cite

Secondary electron emission in Hall thrusters is predicted to lead to space charge saturated wall sheaths resulting in enhanced power losses in the thruster channel.Analysis of experimentally obtained electron-wall collision frequency suggests that the electron temperature saturation, which occurs at high discharge voltages, appears to be caused by a decrease of the Joule heating rather than by the enhancement of the electron energy loss at the walls due to a strong secondary electron emission.2

show abstract

Section: B Determination Of Plasma Parametersmentioning

confidence: 99%

Space charge saturated sheath regime and electron temperature saturation in Hall thrusters

et al. 2005

View full text Add to dashboard Cite

show abstract

“…The GRC facility measured 4.6 m in diameter by 19.5 m in length and was able to maintain a 2:5 10 6 torr while the thruster was operational, and the TAC facility measured 2.4 m in diameter by 9.8 m in length and was able to maintain 4 10 6 torr while the thruster was operational. The probes used to take the measurements at TAC are described in [9], and the probes used to take the GRC data are described in [3]. A curve fit to the beam current-density data is also shown in Fig.…”

Section: A Current-density Modelmentioning

confidence: 99%

“…An estimate of the magnitude of the total current in the plume wings caused by CEX and scattered ion flows due to background neutrals can be determined by using a gridded flux probe [9] which rejects ions with different energy classes. To characterize these effects, current-density measurements are taken with the grid potential varied from 0 to 100 V in 25-V increments, and the data are shown in Fig.…”

Section: A Current-density Modelmentioning

confidence: 99%

Hall Thruster Plume Model for Spacecraft Impingement Torque: Development and Validation

Corey¹,

Snyder²,

Price³

et al. 2008

Journal of Spacecraft and Rockets

View full text Add to dashboard Cite

Space Systems/Loral has implemented the SPT-100 Hall effect thruster onto geostationary spacecraft for primary north-south station keeping, allowing substantial reductions in onboard propellant mass. Consideration of the spacecraft-thruster interactions is necessary when implementing electric propulsion thrusters onto communications satellites. Impingement of high-energy xenon ions on the spacecraft solar arrays and other large surfaces causes torques on the spacecraft that must be accounted for and controlled by the spacecraft control system. Space Systems/ Loral has developed and used a model to predict the impingement torques on the spacecraft, allowing proper design of the spacecraft control system. The impingement model is based on experimental current-density and ion-energy data taken during ground testing. Accommodation-coefficient values for the surfaces being investigated were based on values taken from open literature. Predictions from the plume model were compared with flight control-system data from two Russian-manufactured spacecraft. Modifications to the model were made for current density, based on correlation with the flight torque data. This paper will compare predictions based on this model with flight data from the Space Systems/Loral-manufactured Galaxy 28 and Thaicom 4 geosynchronous commercial spacecraft. Both spacecraft are equipped with an SPT-100 subsystem to perform north-south station keeping.Nomenclature C i = curve-fit coefficient e = elementary charge, 1:6 10 19 C F = force, N f " = current-density distribution function g = gravity constant at sea level, 9:8 m=s 2 j = current density, mA=cm 2 k i = curve-fit coefficient ke i = curve-fit coefficient m = mass, kg p = normal momentum flux, N=m 2 R = distance from the thruster exit plane to a point in space, m R cm = distance from the thruster to the spacecraft center of mass, m T = torque, N m u = current-weighted velocity, m=s v = ion velocity, m=s " = ion energy, eV = angle from the thruster centerline, deg n = normal momentum accommodation coefficient t = tangential momentum accommodation coefficient 0 = normal momentum accommodation coefficient, 0 = tangential momentum flux, N=m 2 = incident angle with respect to surface normal, deg

show abstract

“…Many experimental and modeling studies have been performed for Hall thruster plumes 43,44,45,46 and also for EP missions beyond GEO. 47,48 The plume of the BPT-4000 thruster has been characterized through detailed diagnostic experiments, 49 materials sputter testing and modeling, 50 and spacecraft-level plume effects modeling. 51 Plume effects depend in part on the specific thruster used but also importantly on the spacecraft configuration.…”

Section: Mission Assurancementioning

confidence: 99%

Evaluation of a 4.5 kW Commercial Hall Thruster System for NASA Science Missions

Hofer¹,

Randolph²,

Oh³

et al. 2006

42nd AIAA/ASME/SAE/ASEE Joint Propulsion Conference &Amp;amp; Exhibit

Self Cite

View full text Add to dashboard Cite

The readiness of commercial Hall thruster technology is evaluated for near-term use on competitively-award, cost-capped science missions like the NASA Discovery program. Scientists on these programs continue to place higher demands on mission performance that must trade against the cost and performance of propulsion system options. Solar electric propulsion (SEP) systems can provide enabling or enhancing capabilities to several missions, but the widespread and routine use of SEP will only be realized through aggressive cost and schedule risk reduction efforts. Significant cost and schedule risk reductions can potentially be realized with systems based on commercial Hall thruster technology. The abundance of commercial suppliers in the United States and abroad provides a sustainable base from which Hall thruster systems can be cost-effectively obtained through procurements from existing product lines. A Hall thruster propulsion system standard architecture for NASA science missions is proposed. The BPT-4000 from Aerojet is identified as a candidate for near-term use. Differences in qualification requirements between commercial and science missions are identified and a plan is presented for a low-cost, low-risk delta qualification effort. Mission analysis for Discovery-class reference missions are discussed comparing the relative cost and performance benefits of a BPT-4000 based system to an NSTAR ion thruster based system. The BPT-4000 system seems best suited to destinations located relatively close to the sun, inside approximately 2 AU. On a reference near Earth asteroid sample return mission, the BPT-4000 offers mass performance competitive with or superior to NSTAR at much lower cost. Additionally, it is found that a low-cost, mid-power commercial Hall thruster system may be a viable alternative to aerobraking for some missions.Suggestions for the near-and far-term implementation of commercial Hall thrusters on NASA science missions are discussed.

show abstract

Ion flux, energy, and charge-state measurements for the BPT-4000 Hall thruster

Cited by 24 publications

References 1 publication

Space charge saturated sheath regime and electron temperature saturation in Hall thrusters

Space charge saturated sheath regime and electron temperature saturation in Hall thrusters

Hall Thruster Plume Model for Spacecraft Impingement Torque: Development and Validation

Evaluation of a 4.5 kW Commercial Hall Thruster System for NASA Science Missions

Contact Info

Product

Resources

About