Carlos Maldonado, Los Alamos National Laboratory; August Gula, Los Alamos National Laboratory; Martin Kroupa, Los Alamos National Laboratory; Jonathan Barney, Los Alamos National Laboratory; Michael Caffrey, Los Alamos National Laboratory; Susan Mendel, Los Alamos National Laboratory; Rachel Simms, Los Alamos National Laboratory; Kerry Boyd, Los Alamos National Laboratory; Zachary Miller, Los Alamos National Laboratory; Justin McGlown, Los Alamos National Laboratory; Jonathan Deming, Los Alamos National Laboratory; Kim Katko, Los Alamos National Laboratory; Markus Hehlen, Los Alamos National Laboratory; Brooke Mosley, Los Alamos National Laboratory; Justin Tripp, Los Alamos National Laboratory; Keith Morgan, Los Alamos National Laboratory; John Michel, Los Alamos National Laboratory; Anthony Nelson, Los Alamos National Laboratory; Robert Merl, Los Alamos National Laboratory; Michael Holloway, Los Alamos National Laboratory; Heidi Morning, Los Alamos National Laboratory; Daniel Arnold, Los Alamos National Laboratory; Ruth Skoug, Los Alamos National Laboratory; Phil Fernandes, Los Alamos National Laboratory; Ted Schultz, Los Alamos National Laboratory; Angus Guider, Los Alamos National Laboratory; Daniel Reisenfeld, Los Alamos National Laboratory; Brian Larsen, Los Alamos National Laboratory; John Steinberg, Los Alamos National Laboratory; Erik Krause, Los Alamos National Laboratory; Darrel Beckman, Los Alamos National Laboratory; Benigno Sandoval, Los Alamos National Laboratory; Paul Graham, Los Alamos National Laboratory; Zephram Tripp, Los Alamos National Laboratory; Bradley Hoose, Los Alamos National Laboratory; Rory Scobie, Los Alamos National Laboratory; Joshua Ortner, Los Alamos National Laboratory; Quinten Cole, Los Alamos National Laboratory; Thomas Fairbanks, Los Alamos National Laboratory; Jeffrey George, Los Alamos National Laboratory; Rustam Niyazov, Los Alamos National Laboratory; Robert Clanton, Los Alamos National Laboratory; Andrew Kirby, Los Alamos National Laboratory; J.P. Martinez, Los Alamos National Laboratory; Tracy Gambill, Los Alamos National Laboratory; Melissa Ma, Los Alamos National Laboratory; Kasidit Subsomboon, Los Alamos National Laboratory; Darren Harvey, Los Alamos National Laboratory; Katherine Alano, Los Alamos National Laboratory; Kristina McKeown, Los Alamos National Laboratory; Donathan Ortega, Los Alamos National Laboratory
Keywords: space weather, magnetospheric physics, ionospheric physics, space environment, radiation belts
Abstract:
Legacy space weather instruments provide a wealth of timely data, but the production cycle is long and expensive. These legacy instruments require complex fabrication and assembly efforts requiring larger, heavier, and more powerful operational support systems. Demonstration and Validation (DemVal) projects are designed to quickly mature emerging technologies. The Experiment for Space Radiation Analysis (ESRA) is the latest of a series of DemVal missions built by Los Alamos National Laboratory (LANL), with the focus on a new generation of plasma and energetic particle sensors. The primary motivation is to minimize size, weight, power, and build cost (SWaP-C) while still provide necessary mission data. These new design instruments will be demonstrated by ESRA through testing and on-orbit operations to increase their technology readiness level (TRL) such that they can support the evolution of technology and mission objectives. This project will leverage a commercial off-the-shelf (COTS) CubeSat avionics bus and commercial satellite ground networks to reduce the cost and timeline associated with traditional DemVal missions. The system will launch as a ride share with the DoD Space Test Program (STP); to be inserted in Geosynchronous Transfer Orbit (GTO) and allow observations of the Earths radiation belts.
The ESRA CubeSat consists of two science payloads and several subsystems: These are the Wide-field-of-view Plasma Spectrometer (WPS), the Energetic Charged Particle (ECP) telescope, high voltage power supply (HVPS), payload processor (PP), flight software architecture, and distributed processor module (DPM).
A LANL-designed payload processor will control the experiment, record the data, and communicate with the CubeSat avionics while a distributed processor module (DPM) will provide limited processing at the sensor head locations and packetize data. The (DPM) provides the ability to mount multiple sensors in nontraditional configurations, i.e. sensor heads are not co-located, in order to maximize the ability to conform the sensor suite to any host and optimize fields-of-view.
The ESRA CubeSat will provide measurements of the plasma and energetic charged particle populations in the GTO environment for ions ranging from ~100 eV to ~300 MeV and electrons with energy ranging from 100 keV to 20 MeV. The ESRA mission will additionally demonstrate the potential of CubeSats for both science and space weather monitoring in the radiation belts, serving as a pathfinder to future constellation type missions. To date, there have been no successful CubeSat missions through the radiation belts reported in the open literature. A 6U CubeSat mission to geostationary transfer orbit, called GTOSat, is scheduled for launch in 2021. This mission will measure energetic electrons and protons at a reduced energy range (when compared to ESRA) from ~hundreds of keV to a few MeV. By using a commercial 12U bus, ESRA will, for the first time, demonstrate a low-cost, rapidly deployable spaceflight platform with sufficient SWAP to enable efficient measurements of the energetic particle populations in the dynamic radiation belts.
Wide-field-of-view Plasma Spectrometer (WPS)
WPS is a novel design that presents the ability to dramatically reduce the complexity and associated cost of the traditional top-hat electrostatic analyzer plasma spectrometers. This design acquires a complete plasma measurement in a single voltage sweep and measures a broad field-of-view (FOV) without relying on spacecraft spin or deflection plates, both of which require time and/or additional resources to obtain full distribution measurements. The unique design enables a dramatic reduction of resources (mass, power, size, and cost) compared to cylindrical and spherical section analyzers and top hat designs. The WPS sensor is a revolutionary step forward in electrostatic analyzer design and is the ideal option for 3-axis stabilized spacecraft.
Energetic Charged Particle (ECP) Telescope
The ECP telescope is being designed to measure a broad range of energies for both protons and electrons (100 keV 200 MeV for protons, 100 keV 10 MeV for electrons). To this end, the telescope design will utilize new materials, namely CZT (CdZnTe) semiconductor detectors and GAGG(Ce) (Ce3+-doped Gd3Al2Ga3O12) scintillators. These materials were selected to maximize the range of particle energies which can be reconstructed with limited telescope footprint on the CubeSat. The collimator and shielding are used to limit the rate of detected particles. Tungsten plates between detectors increase the energy required to traverse the telescope, thereby extending the dynamic range of detected particle energies.
Primary motivations for using CZT as a detection material include increased stopping power and a larger dynamic range as compared to silicon. There is a tradeoff in resolution, which is not as important for the application to measurements at higher energy, as the energy bin widths scale with energy (see Figures 4). A primary motivation for using GAGG(Ce), which has an emission maximum around 540 nm, is eliminating the need for wavelength shifting, thereby enabling efficient photodiode readout. Finally, using these materials will provide flight heritage for both of these intriguing detection materials.
This technical paper will further discuss the key experiment objectives (listed below) in addition to how each sensor (WPS & ECP) will address each objective.
1. Science: to study energetic particle dynamics in Earths radiation belts
2. Space Weather: to measure total ionizing dose (TID) as a function of incident charged particle flux
3. Technology Advancement: to demonstrate the capability of next generation space weather sensors and critical subsystems
4. Technology Advancement: to demonstrate the ability and utility of SmallSats beyond low-Earth orbit (LEO)
5. Technology Advancement: to utilize commercial CubeSat technologies and ground station networks to reduce cost and development time
Date of Conference: September 27-20, 2022
Track: Atmospherics/Space Weather