Low-altitude measurements provide a unique vantage point for studying processes occurring in the magnetosphere, taking advantage of the fact that energetic particles move quickly along magnetic field lines. Low-Earth-orbiting (LEO) polar satellites can sample a vast volume of space as they rapidly traverse magnetic field lines, obtaining a radial snapshot of the entire magnetotail in minutes. CINEMA (Cross-scale INvestigation of Earth's Magnetotail and Aurora) is a NASA Small Explorer mission concept with the overarching goal to understand the role of plasma sheet structure and evolution in Earth’s multiscale magnetospheric convection cycle. How the magnetotail maintains steady convection, and when and how it decides to explosively release stored energy, are major unsolved mysteries of space physics. CINEMA’s nine satellites in LEO polar orbits each carry an on-board imager, particle sensors, and magnetometers, and quickly traverse the low-altitude footprint of the magnetotail, capturing its evolution at different scales. CINEMA obtains information about the structure of the magnetotail remotely through its imprint on particle pitch-angle distributions, providing an unprecedented view of particle isotropy boundaries. Mesoscale aurora and bursty energetic particle precipitation serve as tracers of specific mesoscale and kinetic-scale dynamics. Field-aligned currents (FACs) that connect the magnetotail to the ionosphere are sensed by measuring magnetic field variations at each satellite. Together, these observations reveal the physics underlying multiscale magnetotail convection.

How to cite: Millan, R. and Ukhorskiy, S. and the CINEMA Science Team: Remote-Sensing Magnetotail Dynamics from Low Earth Orbit with CINEMA, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-4783, https://doi.org/10.5194/egusphere-egu24-4783, 2024.

We describe the ELectron Microburst Observatory mission, ELMO  which is proposed as  a
CubeSat constellation mission to fully characterize microburst event spatial extent systematically for the first time both in latitude  and longitude. ELMO comprises 4 CubeSats two per orbit plane in two orbit planes. ELMO will fly in a high inclination LEO at about 500 km in altitude. The CubeSats will systematically separate both in latitude and longitude over the mission lifetime and will carry MERIT, Miniaturized Electron and Proton Telescope as the the payload. MERIT has been built,tested and delivered  to fly on NASA's HERMES, Lunar Gateway mission. MERIT is a solid state detector particle telescope with two identical sensor heads pointed zenith- and nadir-wards enabling measurement of both downgpoing and upwelling electrons thereby accurately estimating  electron precipitation into the atmosphere.  MERIT  will measure electron and protons over a wide energy range in multiple differential channels with a very time resolution of less than 4 ms.    

ELMO will quantify for the first time the contribution of microbursts to radiation belt electron loss using systematic coordinated multipoint measurements. Energetic electron precipitation affects atmospheric chemistry and therefore climate change. ELMO measures
microbursts with unprecedented time and energy resolution. ELMO provides critical knowledge of electron loss processes required for quantitative prediction of global electron fluxes.

How to cite: Kanekal, S.: ELMO: ELectron Microburst Observatory mission to study microbursts, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-6388, https://doi.org/10.5194/egusphere-egu24-6388, 2024.

The Swarm-E/Enhanced Polar Outflow Probe (e-POP) is in an elliptic (non-circular) and non-Sun-synchronous polar orbit (81° inclination, 325 km perigee × 1500 km initial apogee). This gives the satellite a unique vantage point among LEO satellites for observing plasma and related space weather processes in the topside ionosphere and thermosphere, especially the altitude variations of specific physical phenomena. The imaging and rapid-scanning ion mass spectrometer (IRM) on Swarm E combines the technique of ion time-of-flight (TOF), hemispherical electrostatic analysis, and 2D positional ion detection (imaging) to resolve the mass-per-charge (M/q), energy-per-charge (E/q), and incident direction of each detected ion, and to simultaneously measure the incident plasma current at high (1-ms) cadence. Data acquired over the 8-year period from launch (September 2013) to December 2021 has enabled the quantitative investigation of several important magnetosphere-ionosphere-thermosphere (MIT) coupling processes and the altitude distributions and variations of the resulting plasma composition, structure, and dynamics in the F-region and topside ionosphere-thermosphere. These include the effects of atmospheric photoelectrons on spacecraft charging, molecular and nitrogen (N+) ion enhancements in the active-time auroral ionosphere, and decameter-scale structures in equatorial plasma bubbles, for example. We present an overview of investigations of the long- (solar-cycle time scale) and short-term (down to substorm time scale) variations of the various observed features and associated phenomena in the context of their impact on MIT coupling.

How to cite: Yau, A., Foss, V., Howarth, A., Kastyak-Ibrahim, M., and White, A.: Investigation of Plasma Composition and Small-Scale Density Irregularities on a Non-circular and Non-Sun-Synchronous Polar Low-Earth-Orbit (LEO) Satellite: Swarm-E e-POP Observations in the F-region and Topside Ionosphere-Thermosphere, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-6986, https://doi.org/10.5194/egusphere-egu24-6986, 2024.

Iridium satellites in low-Earth orbit have transformed our knowledge of geospace by enabling the AMPERE dataset. We employ AMPERE data from October 2009 to December 2021 to examine the interhemispheric asymmetry in Birkeland currents over the span of a solar cycle. We take daily averages of the upward and downward current in both hemispheres and examine the systematic asymmetry by removing the seasonal trend. We find that Birkeland currents are stronger in the Northern Hemisphere than in the South after removing the seasonal trend, consistent with Coxon et al. (2016). We explore how this asymmetry manifests over a solar cycle and compare the variation of the asymmetry to other parameters.

How to cite: Coxon, J., Vines, S., Milan, S., and Anderson, B.: The asymmetry towards stronger Birkeland currents in the Northern Hemisphere, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-11337, https://doi.org/10.5194/egusphere-egu24-11337, 2024.

EZIE, the Electrojet Zeeman Imaging Explorer, is a NASA three-Cubesat Heliophysics mission scheduled to launch in late 2024 or early 2025. It employs four downward and cross-track looking miniaturized radiometers on each of the 6U CubeSat, flying in a pearls-on-a-string managed formation, to measure, for the first time, the two-dimensional structure and the temporal evolution of the electrojets flowing at altitudes of ~100–130 km. The four identical radiometers simultaneously measure polarimetric radiances of the molecular oxygen thermal emission at 118 GHz and employs the Zeeman sensing technique to obtain the current-induced magnetic field vectors at ~80 km, an altitude region very close to the electrojet.  This measurement technique allows for the remote sensing of the meso-scale structure of the electrojets at four different cross-track locations simultaneously at altitudes notoriously difficult to measure in situ. The compact 118-GHz heterodyne spectropolarimeters leverage technologies demonstrated by NASA’s TEMPEST-D and CubeRRT missions and the CubeSat bus from RAVAN, CAT, TEMPEST-D, and CubeRRT. Differential drag maneuvers are used to manage satellite along-track temporal separation to within 2–10 minutes between adjacent satellite to record the electrojet temporal evolution without the need for on-board propulsion. The combination of the sensing technique, compact instrument and Cubesat technologies allow EZIE to cost-effectively obtain never-before “mesoscale” measurements needed to understand how the solar wind energies stored in the magnetosphere are transferred to the thermosphere and ionosphere.  In this paper, we will present an overview of the EZIE mission, its science objectives, the Zeeman sensing technique employed, and the measurement products to be provided.

How to cite: Yee, J.-H., Gjerloev, J., Mosavi-Hoyer, N., Wind-Kelly, R., Swartz, W., and Misra, S.: Overview of the EZIE (Electrojet Zeeman Imaging Explorer) Mission, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-11988, https://doi.org/10.5194/egusphere-egu24-11988, 2024.

From the vantage point of an elliptic, polar, low-earth orbit (81^o inclination, 325 km x 1500 km initial apogee/perigee), CASSIOPE/Swarm-Echo has been observing the ionosphere-thermosphere system for over ten years. The Enhanced Polar Outflow Probe (e-POP) payload onboard collects data on space weather and related phenomena, including measurements of the local magnetic field, low-energy ion and electron energy distributions, high-frequency radio waves (natural and man-made), GPS signals, and aurora. These observations from a non-sun-synchronous orbit over a range of altitudes constitutes a unique data set that allows for investigation of the earth’s magnetic field and related current systems, upper atmospheric dynamics, auroral dynamics, and related coupling processes among the magnetosphere, ionosphere, thermosphere, and plasmasphere. This presentation will highlight the discoveries of the ten years of e-POP operation, including recent work on plasma waves generated by moving charged space objects and machine-learning techniques applied to analysis of magnetic field data and auroral images. We will also present some of the new Swarm-Echo data products and system tools available for use and look at the future direction of both the mission and the evolving data set.

How to cite: Howarth, A., Yau, A., Bernhardt, P., James, G., Knudsen, D., Langley, R., and Miles, D.: Ten Years of Low-Earth Orbit Observations from CASSIOPE/Swarm-Echo, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-12382, https://doi.org/10.5194/egusphere-egu24-12382, 2024.

The RADiation Impacts on Climate and Atmospheric Loss Satellite (RADICALS) is a low-Earth orbiting Canadian small satellite mission investigating the transport of space radiation into the atmosphere, and its impact on Earth’s climate. Scheduled for launch in late 2026, the mission will launch into a polar orbit with an integrated payload comprising two back-to-back look direction High Energy Particle (HEP) telescopes, an X-Ray Imager (XRI) to remote sense energetic particle precipitation using back-scattered Bremsstrahlung X-rays, and a boom mounted FluxGate Magnetometer (FGM) and Search Coil Magnetometer (SCM). Using an innovative Thomson spin-stabilized configuration, the satellite will sample the pitch angle distributions in the spin-plane twice per spin. The back-to-back HEP look directions allow for a contemporaneous view of the down-going and back-scattered up-going electrons, at the same time as XRI remote-senses the related Bremsstrahlung, and the magnetometers provide in-situ magnetic signatures of a range of plasma waves. The key measurement of the pitch angle resolved energetic electron precipitation (EEP) and related back-scatter, including a resolved loss cone, will allow a detailed assessment of the energetic particle energy input to the atmosphere. Measurements of EEP, in addition to measurements of solar energetic particle (SEP) precipitation, will represent a critical data set for assessing the role of space radiation in the climate system, for example through the catalytic destruction of ozone in the middle atmosphere by NOx and HOx. Accurately quantifying the impacts of this space radiation on climate requires accurate and loss cone-resolved characterization of the flux of these precipitating energetic particles for inclusion into whole atmosphere models. The RADICALS explorer will also enable research into potentially catastrophic space-weather radiation effects on satellite infrastructure, and assess impacts on space weather-related interruptions to high frequency radio communications including in relation to aircraft operations in polar regions. Additional cube- and micro-satellite missions, together with the RADICALS, could form a powerful mini--constellation exploring the space weather-climate system.

How to cite: Ozeke, L., Mann, I., Cully, C., Milling, D., Lipsett, M., Ranking, R., McWilliams, K., Fiori, R., Cullen, D., Fedosejevs, R., Enno, G., Zee, R., Conners, M., Ward, W., Olifer, L., Marshall, R., Barona, D., Yau, A., and Howarth, A.: The RADiation Impacts on Climate and Atmospheric Loss Satellite (RADICALS) Mission, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-13334, https://doi.org/10.5194/egusphere-egu24-13334, 2024.

The charge to the space science community is to improve specification and forecast of the low Earth orbit (LEO) space environment to provide reliable collision avoidance and risk assessment analyses for space traffic management and reduce the number of false conjunction warnings. The challenge is that the prediction of LEO object trajectories is severely limited. This is due primarily to poorly captured variability in neutral density estimates during space weather events, resulting in large and variable position errors of all resident space objects across LEO. To improve operations in LEO, the specification and forecast of the thermosphere neutral mass density must improve.

Most recently launched LEO satellites are equipped with global navigation satellite system (GNSS) devices, making them excellent sources of continuous orbit ephemeris to enable precision orbit determination (POD). Many are also equipped with attitude and vehicle knowledge to allow for the construction of an accurate force model. Combining these “data of opportunity” from LEO satellites with POD processing tools offers the possibility of extracting thermospheric mass density information regularly and globally from the multitude of GNSS-equipped LEO satellites in operation today.

This talk explores this possible trove of LEO space environment data by investigating methods and providing specificity to the level of data information required to provide useful mass density outcomes. The ICESAT-2 spacecraft is used as a test vehicle for this type of analysis. The NASA GSFC GEODYN POD software is employed to produce precise science orbits for the ICESAT-2 spacecraft. These precise science orbits are then used to extract mass density estimates along specified orbital arcs. Simulation is also employed to address the potential errors of system requirements and how they can influence the thermospheric mass density estimate from LEO spacecraft. The future GDC mission will also be highlighted as a much-needed LEO space environment resource for direct multi-point measurements of the thermospheric gas and ionospheric plasma. These direct neutral measurements will enable a careful validation of POD-extracted densities. By fully characterizing all free-stream parameters, GDC is also a well-equipped constellation for studying the gas-surface interactions critical for drag research.

How to cite: Thayer, J., Pilinski, M., Sutton, E., Waldron, Z., and Ray, V.: LEO Satellites as Sensors for Thermospheric Mass Density and Drag Research  , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-14017, https://doi.org/10.5194/egusphere-egu24-14017, 2024.

SBUDNIC is a student-managed project that demonstrated the potential for efficient, inexpensive, open-source satellite design and production by (1) launching a 3U CubeSat with a reproducible parts cost of 6.210 USD; (2) completing design, development, and testing within 14 months; and (3) doing this in a team of under 30 undergraduate and graduate students with no prior Space systems experience.

SBUDNIC’s low unit cost precluded the use of most Space-qualified components, leading to novel subsystem designs that deviated from industry practices. A particularly important contribution to Space technology was a Kapton drag sail designed to stabilize SBUDNIC and accelerate its deorbiting.

Over SBUDNIC's lifetime, the team used publicly available positioning data (collected by the United States Space Force, and as compiled and shared on space-track.org) to monitor the trajectory of SBUDNIC and the other 3U satellites that launched with it. SBUDNIC's reentry from 550 km was swift, especially in comparison to the 3U reference satellites: it occurred on August 10, 2023, after only 441 days in Space. By comparison, the orbit of the 3U reference satellites decayed around 50 kilometers over that same time span. SBUDNIC's rapid decay therefore suggests that the drag sail was effective and functioned to purpose. SBUDNIC’s deorbit was 95% faster than anticipated by pre-launch engineering simulations, suggesting a far-higher-than-average atmospheric density at its altitude, likely influenced by heightened solar activity, although further investigation might identify additional contributing factors to such accelerated descent.

SBUDNIC's key goal of making Space exploration more accessible is not limited to the availability of the parts used. The entire satellite project follows the Open Architecture philosophy, and significant effort was made to engage student and hobbyist communities with the mission. The timely program execution, launch, and subsequent deorbit of SBUDNIC demonstrated techniques for manufacture and design that can facilitate low-cost, short-timeline satellite programs for many applications. Additionally, SBUDNIC's orbital decay data sets, though unintended, offer scientific value for Space Weather studies, underscoring the potential of LEO satellites in understanding geospace dynamics.

The SBUDNIC project was a collaboration between the National Research Council of Italy and the Brown University School of Engineering, with support from D-Orbit, AMSAT-Italy, La Sapienza-University of Rome and NASA Rhode Island Space Grant.

How to cite: Bigagli, L. and the SBUDNIC Team (2): Demonstrating the accessibility of Space with SBUDNIC, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-19763, https://doi.org/10.5194/egusphere-egu24-19763, 2024.

Understanding the dynamics of energetic electrons in the radiation belts is key to protect space borne equipment and astronauts on-board spacecraft missions. Therefore, global reconstruction of the near-Earth radiation environment should be available at all times, radial distances and geomagnetic latitudes. Low Earth Orbit (LEO) satellites provide a large data set of rapid observations of the radiation belt region over a wide range of magnetic local times (MLT). However, the use of this data set is rather complicated due to possible proton contamination of electron fluxes and the observation of electron precipitation, leading to high variability of electron measurements, considerable instrumental errors and the need for background correction. In this study, we present a new intercalibration method for satellite measurements of energetic electrons in the radiation belt region using a data assimilation approach. Our aim is to intercalibrate the electron flux measurements of the POES satellites NOAA-15,-16,-17,-18,-19 and MetOp-02 against RBSP observations for the period October 2012 to December 2013. For this, we use a reanalysis of the radiation belt region, obtained by assimilating RBSP and GOES electron data into 3-D Versatile Electron Radiation Belt (VERB-3D) code simulations via a standard Kalman filter. Since the reanalysis provides global reconstruction of the state of the system. We compare the POES/MetOp data with our reanlysis and estimate the flux ratios at each time, location and energy. These ratios are averaged over time and space to obtain energy dependent recalibration coefficients. In order to validate our results, we perform a traditional conjunction study between POES/MetOp satellites and the Van Allen probes. Similarly, we estimate flux ratios for all the found conjunctions and calculate the corresponding energy dependent recalibration coefficients. The conjunction coefficients and the DA estimated coefficients show very good agreement. Additionally, the use of data assimilation allows for improved statistics, as the number of possible ratios is considerably improved. The recalibration coefficients estimated using the our data assimilation approach leads to good resemblance and agreement between the recalibrated POES/MetOp data set and the RBSP observations.

How to cite: Castillo Tibocha, A. M., Shprits, Y. Y., Aseev, N. A., Smirnov, A., Drozdov, A., Cervantes, S. C., Michaelis, I., Garcı́a Peñaranda, M., and Wang, D.: Can we intercalibrate satellite measurements by means of data assimilation? An attempt on LEO satellites, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-20341, https://doi.org/10.5194/egusphere-egu24-20341, 2024.