Feasibility of Large High-Power Solar Electric Propulsion Vehicles: Issues and Solutions

Capadona, Lynn A.; Woytach, Jeffrey M.; Doehne, Thomas; Hoffman, David J.; Klem, Mark D.; Christie, Robert; Pencil, Eric; Hickman, Tyler A.; Scheidegger, Robert J.

doi:10.2514/6.2011-7251

Cited by 14 publications

(6 citation statements)

References 13 publications

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“…These same criteria are embedded in more recent NASA papers on SEP mission studies. [23,24,25,26] A summary of each of the necessary attributes and the applicability of UltraFlex/MegaFlex technology is tabulated below. …”

Section: Sep Arrays -Critical Design Criteriamentioning

confidence: 99%

MegaFlex - The Scaling Potential of UltraFlex Technology

Murphy¹

2012

53rd AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics and Materials Conference

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4
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NASA has near-term needs for solar electric propulsion power sources from 5 to 30 kW and longer term goals for SEP tugs as large as 300 kW and beyond. UltraFlex is a high-TRL solar array technology that spans the initial range of power levels with unmatched performance in specific power, stiffness, and strength. This technology has been to Mars and is the baseline for the NASA Orion Multi-Purpose Crew Vehicle (MPCV), as well as upcoming flights of the Orbital Cygnus spacecraft for Commercial Resupply Services (CRS) to the space station. MegaFlex is UltraFlex technology, with two enhancements to the compaction of stowage to allow a two-wing configuration to provide power levels from 10 kW to 1 MW with near-term multi-junction cell efficiencies. This technology elegantly meets the SEP technology development need for true scalability, with a high-performance solution that uniquely allows for complete ground test and validation of up to a 350 kW array wing in existing facilities. Given the compaction capabilities of MegaFlex, it is an enabling technology for any kilowatt level where the power needed is more than the stowage volume allows with standard UltraFlex or alternate approaches. MegaFlex achieves similar performance characteristics as UltraFlex with specific power up to 200 W/kg and also higher stiffness (>3x) and strength (>5x) than conventional arrays.

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Section: Sep Arrays -Critical Design Criteriamentioning
confidence: 99%

MegaFlex - The Scaling Potential of UltraFlex Technology
Murphy¹
2012
53rd AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics and Materials Conference
16
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4
0
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“…In addition to extended lifetimes, recent trends in space power generation are expected to make an order of magnitude higher power levels available for propulsion. 6 The U.S. Air Force Research Laboratory (AFRL) projects that electric thrusters will need to be capable of processing 100-200 kW of power in the near-to mid-term, dwarfing the 0.5 to 12 kW range of recent focus. 7 At the moderate specific impulse of AFRL interest (between 2000-6000 seconds), this translates to roughly 330-660 A of discharge current, 1-2 orders of magnitude higher than currents commonly used in electric thrusters today (e.g.…”

Section: Introductionmentioning
confidence: 99%

Exploration of RF-Controlled High Current Density Hollow Cathode Concepts
Plasek
¹
,
Jorns
²
,
Choueiri³
et al. 2012
48th AIAA/ASME/SAE/ASEE Joint Propulsion Conference &Amp;amp; Exhibit
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Exploration of a novel RF-Controlled HollowCathode concept is presented using finite element analysis. Commercial software is used to model the extent of RF power absorption in one configuration of such a cathode in order to describe whether the RF power is localized as in a "stinger" concept or is projected downstream to lower the emission current density while maintaining a constant discharge current. Plasma conductivity along the major axis is calculated from a baseline high current density lanthanum hexaboride hollow cathode and is used in the modeling of RF power absorption by the internal plasma. It was found that within a maximum axial distance from the orifice, a direct coaxial-cathode mating can lead to high percentages (>96%) of localized microwave power absorption. The configuration analyzed acted more as a stinger, as approximately 62% of the RF power was absorbed within 2 mm of the inner coaxial conductor tip. Xenon gas breakdown using RF waves was explored and deemed practical for the cathode parameters studied. RF heating of the emitter prior to plasma ignition was also examined, but low RF power absorption (<5%) without a lossy plasma suggested poor feasibility of this potential function.

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“…The notion of using SEP in near-Earth space has been studied for decades [1][2][3][4][5][6][7][8]. NASA's current architecture planning, technology roadmaps and goals for ongoing technology development imply near-term utility of high power SEP.…”

Section: Introductionmentioning
confidence: 99%

Solar electric propulsion demonstration mission 30 kW-class concept description
Deininger¹,
Enger²,
Hackel³
et al. 2014
2014 IEEE Aerospace Conference
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A 30 kW solar electric propulsion (SEP) technology demonstration mission (TDM) concept is described. The mission concept is formulated in response to NASA's BAA and demonstrates a modular and extensible solar electric propulsion system. It launches in early 2018 and flies multiple LEO-GEO transits over the 1-2 year-long operations period. The 30 kW SEP TDM Space Vehicle (SV) is based on integrated SEP and Bus Modules allowing parallel development and efficient integration. The SEP Module includes three 12 kW Hall thruster strings (3 + 0) which can be operated singly, in pairs or simultaneously for full power operations of all 3 together.Advanced, light-weight, blanket solar array technology is employed for the SEP TDM instead of typically used, rigid panel technology. MegaFlex technology, using two 10 mdiameter wings, is baselined. The power and propulsion systems are at sufficient specific power to demonstrate the movement of large payloads from LEO to higher energy orbits at performance values consistent with future higher power electric propulsion capabilities (Isp, thrust-to-power, power-tomass). The SEP TDM, and its SEP Module concept, represents a key infusion point to a reusable electric propulsion stage by demonstrating transfers from LEO to GEO and back to LEO. This set of high ΔV trajectories demonstrates long-term SEP operations and flies the SEP TDM Space Vehicle through the radiation belts, sustained plasma environments, diverse distributed inertia spacecraft control environments and repeated spacecraft occultations. The space vehicle hosts several secondary payloads to enhance science and technology return from the mission.

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Feasibility of Large High-Power Solar Electric Propulsion Vehicles: Issues and Solutions

Cited by 14 publications

References 13 publications

MegaFlex - The Scaling Potential of UltraFlex Technology

MegaFlex - The Scaling Potential of UltraFlex Technology

Exploration of RF-Controlled High Current Density Hollow Cathode Concepts

Solar electric propulsion demonstration mission 30 kW-class concept description

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