Development and Testing of the Dawn Ion Propulsion System

Brophy, John R.; Etters, Michael; Gates, Jason; Garner, Charles E.; Klatte, Marlin; Lo, Chaomei; Marcucci, M.; Mikes, Steve; Pixler, Greg; Nakazono, Barry

doi:10.2514/6.2006-4319

Cited by 32 publications

(18 citation statements)

References 3 publications

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“…(18) shows that the minimization problem in Eq. (7) still holds: for a particular instant of time, the acceleration required from the SEP system can be minimized by finding the optimal solar sail pitch and yaw angles.…”

Section: Perturbations Due To Non-uniform Earth Gravity Fieldmentioning

confidence: 99%

“…SEP is highly efficient as it enables high specific impulses. It has flown on multiple missions including the NSTAR ion engines on Deep Space 1 (1998) and Dawn (2007), the PPS1350 Hall thruster on SMART-1 (2003), the QinetiQ's T5 thrusters on GOCE (2009) and the Aerojet BPT4000 thruster on the Advanced Extremely High Frequency geostationary satellite (2010) [16][17][18]. This results in a high TRL and a low AD 2 .…”

Section: Introductionmentioning

confidence: 99%

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Displaced geostationary orbits using hybrid low-thrust propulsion

et al. 2012

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In this paper, displaced geostationary orbits using hybrid low-thrust propulsion, a complementary combination of Solar Electric Propulsion (SEP) and solar sailing, are investigated to increase the capacity of the geostationary ring that is starting to become congested. The SEP propellant consumption is minimized in order to maximize the mission lifetime by deriving semi-analytical formulae for the optimal steering laws for the SEP and solar sail accelerations. By considering the spacecraft mass budget, the performance is also expressed in terms of payload mass capacity. The analyses are performed both for the use of pure SEP and hybrid low-thrust propulsion to allow for a comparison. It is found that hybrid lowthrust control outperforms the pure SEP case both in terms of payload mass capacity and mission lifetime for all displacements considered. Hybrid low-thrust propulsion enables payloads of 255 to 487 kg to be maintained in a 35 km displaced orbit for 10 to 15 years. Adding the influence of the 2 J and 2,2 J terms of the Earth"s gravity field has a small effect on this lifetime, which becomes almost negligible for small values of the sail lightness number. Finally, two SEP transfers that allow for an improvement in the performance of hybrid low-thrust control are optimized for the propellant consumption by solving the accompanying optimal control problem using a direct pseudospectral method. The first type of transfer enables a transit between orbits displaced above and below the equatorial plane, while the second type of transfer enables customized service for which a spacecraft is transferred to a Keplerian parking orbit when geostationary coverage is not needed. While the latter requires a modest propellant budget, the first type of transfer comes at the cost of an almost negligible SEP propellant consumption.

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Section: Perturbations Due To Non-uniform Earth Gravity Fieldmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Displaced geostationary orbits using hybrid low-thrust propulsion

et al. 2012

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“…55 Dawn utilizes an NSTAR ion thruster based EP system for primary propulsion. 5 This system represents the current state of the art for NASA deep space SEP systems. This section examines the benefit that a SEP system based on the 4.5 kW BPT-4000 commercial Hall thruster could have for Discovery class deep space missions.…”

Section: Mission Applicationsmentioning

confidence: 99%

“…For comparison, the commercial components considered here will be evaluated against requirements for the Dawn mission, selected under NASAs Discovery Program to visit two major main-belt asteroids, which will be the first use of an ion propulsion system on a full-up NASA science mission. 5 The Dawn IPS includes three NSTAR ion thrusters and accompanying gimbals mounted on the exterior of the spacecraft, two PPUs, a xenon tank, and propellant management hardware inside of the spacecraft. The use of Dawn as a benchmark for the initial evaluation of commercial components is appropriate because (1) it is an active mission in a cost-capped program, (2) it is using an EP subsystem for primary propulsion, and (3) the mission assurance requirements are mature.…”

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

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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.

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“…4 Initial thruster development work was led by GRC and included significant performance testing, 5 a 2000-hour wear test, 6 an integrated test with other subsystem components, 7 and more recently an ongoing wear test 8 and a multi-thruster array test. 9 The thruster technology was transferred to NEXT industry partner Aerojet, which designed and fabricated a flight-like Prototype Model (PM) thruster.…”

mentioning

confidence: 99%

Environmental Testing of the NEXT PM1 Ion Engine

Snyder¹,

Anderson²,

Noord³

et al. 2007

43rd AIAA/ASME/SAE/ASEE Joint Propulsion Conference &Amp;amp; Exhibit

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The NEXT propulsion system is an advanced ion propulsion system presently under development that is oriented towards robotic exploration of the solar system using solar electric power. The subsystem includes an ion engine, power processing unit, feed system components, and thruster gimbal. The Prototype Model engine PM1 was subjected to qualification-level environmental testing to demonstrate compatibility with environments representative of anticipated mission requirements. Thruster functional testing was performed before and after the vibration and thermal-vacuum tests. Random vibration testing, conducted with the thruster mated to the breadboard gimbal, was executed at 10.0 G rms for two minutes in each of three axes. Thermal-vacuum testing included a deep cold soak of the engine to temperatures of -168 °C and thermal cycling from -120 °C to 203 °C. Although the testing was largely successful, several issues were identified including the fragmentation of potting cement on the discharge and neutralizer cathode heater terminations during vibration which led to abbreviated thermal testing, and generation of particulate contamination from manufacturing processes and engine materials. Thruster performance was nominal throughout the test program, with minor variations in some engine operating parameters likely caused by facility effects. Discharge cathode ignition times, however, were found to have a significant dependence on engine temperature. There were no significant changes in engine performance as characterized by engine operating parameters, ion optics performance measurements, and beam current density measurements, indicating no significant changes to the hardware as a result of the environmental testing. In general, the NEXT PM1 engine and the breadboard gimbal were found to be well-designed against environmental requirements based on the results reported herein, although there were issues uncovered during the testing. After resolution of the findings from this test program the hardware environmental qualification program can proceed with confidence.

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Development and Testing of the Dawn Ion Propulsion System

Cited by 32 publications

References 3 publications

Displaced geostationary orbits using hybrid low-thrust propulsion

Displaced geostationary orbits using hybrid low-thrust propulsion

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

Environmental Testing of the NEXT PM1 Ion Engine

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