USAFA Integrated Miniaturized Electrostatic Analyzer (iMESA)—An Undergraduate Space Weather Constellation

McHarg, M. G.; Neal, P. C.; Taormina, Nikolas; Strom, Alexander

doi:10.1002/2015sw001284

Cited by 8 publications

(2 citation statements)

References 13 publications

(14 reference statements)

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“…A constellation of these instruments has been developed to cover a range of orbits thus allowing for the collected data to act as multipoint boundary conditions which can then be assimilated into environmental models for the purpose of increasing their space weather forecasting (Balthazor et al, 2015; McHarg et al, 2015). The iMESA‐R has been integrated and launched as a science payload on‐board the Green Propellant Infusion Mission (GPIM), Orbital Test Bed (OTB), Space Test Program Satellite 4 (STPSat‐4), STPSat‐5, and the Space Test Program Houston 6 (STP‐H6) science payload pallet.…”

Section: Imesa‐r Constellationmentioning

confidence: 99%

Calibration and Initial Results of Space Radiation Dosimetry Using the iMESA‐R

et al. 2020

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The integrated Miniaturized Electrostatic Analyzer‐Reflight (iMESA‐R) is a space weather instrument designed to measure plasma density, temperature, and spacecraft charging, along with total ionizing dose and dose rate. A constellation consisting of five nearly identical instruments has been designed and developed to act as science payloads hosted on‐board Department of Defense satellites operating in low‐Earth orbit. To validate the dosimetry component of the iMESA‐R, a radiation test study was performed to calibrate the dosimeter and ascertain the attenuation due to the instrument aluminum housing. An 80 curie Cobalt‐60 radioisotope source emitting beta, X‐ray, and gamma ray radiation decay products was used to calibrate the dosimeter response as a function of distance and instrument shielding. We present results of the calibration study along with initial on‐orbit data presented from the first operational iMESA‐R hosted on‐board Space Test Program Satellite 5 in a polar Earth orbit. The initial on‐orbit data demonstrate the ability to map the radiation environment, particularly the South Atlantic Anomaly and the auroral regions using total ionizing dose rate due to electrons of E > 1.5 MeV and protons of E > 25 MeV.

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Section: Imesa‐r Constellationmentioning

confidence: 99%

Calibration and Initial Results of Space Radiation Dosimetry Using the iMESA‐R

et al. 2020

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“…CHAWS [23][24][25]. There exist several reviews on the subject [26][27][28], the primary impetus focused around better understand spacecraft charging and related electrostatic discharge/arcing events, with recent work considering multi-body charging problems and LEO charging [18,[29][30][31][32]. There has also been interest in the applications of the Lorentz force resulting from a charged satellite moving through the Earth's magnetic field for satellite control [33,34] and the application of Coulomb forces in geostationary Earth orbit (GEO) for touchless actuation [35].…”

Section: Nomenclature Constantsmentioning

confidence: 99%

Numerical Predictions for On-Orbit Ionospheric Aerodynamics Torque Experiment

Capon

Lorrain

Smith

et al. 2020

2020 IEEE Aerospace Conference

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Accurate modelling of the aerodynamic interaction between the space environment and Low Earth Orbit (LEO) objects improves our ability to understand, predict and control their motion. A neglected aspect of the LEO aerodynamics problem is the charged aerodynamic interaction of these objects with the ionosphere, i.e. ionospheric aerodynamics. This work describes a prospective on-orbit ionospheric aerodynamic experiment (IEX) that aims to improve our fundamental understanding of ionospheric aerodynamics and provide in-situ data to support ground-based experiment and numerical efforts. IEX involves the charged aerodynamic control of a formation of two 6U CubeSats. Through the establishment of an optical inter-satellite link (ISL), ionospheric torques induced through the asymmetric charging of High Voltage Panels (HVP) will be measured via the integrated buildup in reaction wheel (RW) speed required to maintain ISL quality. The purpose of this work is to provide preliminary estimates of RW speed buildups to establish measurement detection threshold and ISL control loop feedback rate requirements for the experiment. Here, induced torque estimates are made using the Particle-in-Cell (PIC)/Direction Simulation Monte Carlo (DSMC) simulations using the PIC-DSMC code, pdFOAM. These torque predictions are applied to a digital twin simulation of the satellite formation featuring couple dynamics, space environment and flight software models using the astrodynamics framework, Basilisk, and in-house space environment interaction analysis tool, rayMAN. Given a 500 km altitude circular orbit with a 42 o inclination with ion number densities (ni) ranging between O(10 11 − 10 12 ) m −3 , pdFOAM simulations predicted an induced torque of O(−0.25) µN m given a HVP surface potential (φP ) of −100 V for both the high and low density cases. An unexpected result was a net thrust prediction for the low-density cases caused by indirect thrust forces that arise from plasma sheath driven ion acceleration. Uncertainties surrounding appropriate boundary conditions for wake surface are hypothesised to have contributed to this result and are a key focus for future work. Considering an induced torque of −0.25 µN m and accounting for aerodynamic, solar radiation pressure and gravity-gradient torques, Basilisk simulations predicted an integrated buildup of 25 − 50 RPM over a 10 minute period. Future work discussed includes: attitude determination errors resulting from uncertainties in the ISL, controller errors from discrete-time effects and magnetically induced torques in the digital twin simulation.

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Charged aerodynamics: Ionospheric plasma drag on objects in low-Earth orbit

Lafleur

2023

Acta Astronautica

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USAFA Integrated Miniaturized Electrostatic Analyzer (iMESA)—An Undergraduate Space Weather Constellation

Abstract: Key Points Air Force Academy cadets design and build a space weather constellation Instruments measure plasma density and temperature, spacecraft charging, total dose, and dose rate Increasing density of in situ measurements improves space weather forecast

Cited by 8 publications

References 13 publications

Calibration and Initial Results of Space Radiation Dosimetry Using the iMESA‐R

Calibration and Initial Results of Space Radiation Dosimetry Using the iMESA‐R

Numerical Predictions for On-Orbit Ionospheric Aerodynamics Torque Experiment

Charged aerodynamics: Ionospheric plasma drag on objects in low-Earth orbit

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