Low-Thrust Geostationary Transfer Orbit (LT2GEO) Radiation Environment and Associated Solar Array Degradation Modeling and Ground Testing

Messenger, S.; Wong, Franklin J.; Hoang, Bao; Cress, Cory D.; Walters, Robert J.; Kluever, Craig A.; Jones, G.M.

doi:10.1109/tns.2014.2364894

Cited by 28 publications

(15 citation statements)

References 15 publications

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“…The calculation of optimal trajectories for EOR/low‐thrust transfers has been a topic of active research since the mid‐1970s (Messenger et al, ). A particularly significant challenge for the optimization process is taking into account diminishing thrust due to power loss (addressed recently by Kluever & Messenger, ).…”

Section: Satellite Trajectoriesmentioning

confidence: 99%

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Solar Cell Degradation Due to Proton Belt Enhancements During Electric Orbit Raising to GEO

et al. 2019

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The recent introduction of all‐electric propulsion on geosynchronous satellites enables lower‐cost access to space by replacing chemical propellant. However, the time period required to initially raise the satellite to geostationary orbit (GEO) is around 200 days. During this time the satellite can be exposed to dynamic increases in trapped flux, which are challenging to model. To understand the potential penalty of this new technique in terms of radiation exposure, the influence of several key parameters on solar cell degradation during the electric orbit raising period has been investigated. This is achieved by calculating the accumulation of nonionizing dose through time for a range of approaches. We demonstrate the changes in degradation caused by launching during a long‐lived (hundreds of days) enhancement in megaelectron volt trapped proton flux for three different electric orbit raising scenarios and three different thicknesses of coverglass. Results show that launching in an active environment can increase solar cell degradation due to trapped protons by ∼5% before start of service compared with a quiet environment. The crucial energy range for such enhancements in proton flux is 3–10 MeV (depending on shielding). Further changes of a few percent can occur between different trajectories, or when a 50‐μm change in coverglass thickness is applied.

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Section: Satellite Trajectoriesmentioning

confidence: 99%

“…However, the raising process takes ∼200 days, in comparison to just a few days for chemical propulsion (Horne & Pitchford, ). During this time, performing multiple passes through the Van Allen belts has been shown to significantly increase nonionizing radiation dose from trapped protons (Messenger et al, ).…”

Section: Introductionmentioning

confidence: 99%

Solar Cell Degradation Due to Proton Belt Enhancements During Electric Orbit Raising to GEO

et al. 2019

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“…We then compared the static percentiles to the Monte Carlo 95th percentile fluence to determine if a single static percentile could approximate the full Monte Carlo simulation. Given the past history of solar array sensitivity to protons, we chose 4-10 MeV protons as representative [7], [8], although other energies may be important depending on the solar cell material, covering, and backing.…”

Section: Proton/ap9mentioning

confidence: 99%

“…We focused on 0.5-2 MeV electrons as being the most likely to cause solar array damage. [7], [8] We compared the 95th percentile integral electron fluence from the Monte Carlo run with different static percentile integral electron fluence from the command line run for the GEO1 spiral trajectory. We first looked at electrons with MeV in energy and determined that a static 80th percentile is a good approximation for the 95th percentile fluence.…”

Section: Electron/ae9mentioning

confidence: 99%

Using Static Percentiles of AE9/AP9 to Approximate Dynamic Monte Carlo Runs for Radiation Analysis of Spiral Transfer Orbits

Kwan

O’Brien

2015

IEEE Trans. Nucl. Sci.

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The Aerospace Corporation performed a study to determine whether static percentiles of AE9/AP9 can be used to approximate dynamic Monte Carlo runs for radiation analysis of spiral transfer orbits. Solar panel degradation is a major concern for solar-electric propulsion because solar-electric propulsion depends on the power output of the solar panel. Different spiral trajectories have different radiation environments that could lead to solar panel degradation. Because the spiral transfer orbits only last weeks to months, an average environment does not adequately address the possible transient enhancements of the radiation environment that must be accounted for in optimizing the transfer orbit trajectory. Therefore, to optimize the trajectory, an ensemble of Monte Carlo simulations of AE9/AP9 would normally be run for every spiral trajectory to determine the 95th percentile radiation environment. To avoid performing lengthy Monte Carlo dynamic simulations for every candidate spiral trajectory in the optimization, we found a static percentile that would be an accurate representation of the full Monte Carlo simulation for a representative set of spiral trajectories. For 3 LEO to GEO and 1 LEO to MEO trajectories, a static 90th percentile AP9 is a good approximation of the 95th percentile fluence with dynamics for 4-10 MeV protons, and a static 80th percentile AE9 is a good approximation of the 95th percentile fluence with dynamics for 0.5-2 MeV electrons. While the specific percentiles chosen cannot necessarily be used in general for other orbit trade studies, the concept of determining a static percentile as a quick approximation to a full Monte Carlo ensemble of simulations can likely be applied to other orbit trade studies. We expect the static percentile to depend on the region of space traversed, the mission duration, and the radiation effect considered.Index Terms-AE9/AP9 trapped radiation and plasma model, solar-electric propulsion, spiral transfer orbits.

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“…In this paper we contrast the cumulative damage from extreme electron enhancements with that from extreme SEPEs, while noting that a complete analysis of which particle population poses the greater overall threat would need to include a bespoke assessment of the vulnerability of spacecraft components to SEE and indeed the phenomenon of internal dielectric charging (which we will examine in a separate paper). For example, electric orbit raising missions may use trajectories that spend a considerable amount of time in the trapped proton belt, likely resulting in protons being the dominant particle species for displacement damage to solar cells (Messenger et al, ).…”

Section: Introductionmentioning

confidence: 99%

Radiation Effects on Satellites During Extreme Space Weather Events

et al. 2018

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High‐energy trapped electrons in the Van Allen belts pose a threat to the survivability of orbiting spacecraft. Two key radiation effects are total ionizing dose and displacement damage dose in components and materials, both of which cause cumulative and largely irreversible damage. During an extreme space weather event, trapped electron fluxes in the Van Allen belts can increase by several orders of magnitude in intensity, leading to an enhanced risk of satellite failure. We use extreme environments generated by modeling and statistical analyses to estimate the consequences for satellites in terms of the radiation effects described above. A worst‐case event could lead to significant losses in power generating capability—up to almost 8%—and cause up to four years' worth of ionizing dose degradation, leading to component damage and a life‐shortening effect on satellites. The consequences of such losses are hugely significant given our increasing reliance on satellites for a vast array of services, including communication, navigation, defense, and critical infrastructure.

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Low-Thrust Geostationary Transfer Orbit (LT2GEO) Radiation Environment and Associated Solar Array Degradation Modeling and Ground Testing

Cited by 28 publications

References 15 publications

Solar Cell Degradation Due to Proton Belt Enhancements During Electric Orbit Raising to GEO

Solar Cell Degradation Due to Proton Belt Enhancements During Electric Orbit Raising to GEO

Using Static Percentiles of AE9/AP9 to Approximate Dynamic Monte Carlo Runs for Radiation Analysis of Spiral Transfer Orbits

Radiation Effects on Satellites During Extreme Space Weather Events

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