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DESCRIPCION DEL TRABAJO EXPERIMENTAL
PROJECT DESCRIPTION
The Scintillation Prediction Observations Research Task (SPORT) is a 6U CubeSat satellite mission designed to investigate space weather effects on space-based radio systems. Solar and geomagnetic storms cause the ionosphere to become a turbulent plasma, similar to turbulent water in a Jacuzzi®. Just as turbulent water distorts an optical image, turbulent ionospheric plasma disrupts radio waves as they attempt to propagate through the disturbed medium. The resulting scintillation of ionospheric radio waves routinely causes outages in communication and navigation systems; thus, it is imperative to predict them. The joint U.S.- Brazilian SPORT mission is dedicated to advancing NASA’s capabilities in forecasting these ionospheric scintillations.
ACCOMPLISHMENTS
The SPORT satellite is being developed to fly in circular low Earth orbit at an altitude of ≈400 km and an inclination of 52° for a nominal 1-year mission lifetime. The satellite is instrumented with the latest space environment sensors available to date. Plasma densities and temperatures, along with electric fields, will be measured by the Utah State University Space Weather Probes. Ion velocities and temperatures will be measured by the Ion Velocity Meter (IVM) developed by the University of Texas at Dallas. Remote sensing of electron density profiles, as well as total electron content and scintillation values on-orbit, will be provided by Compact Total Electron Content Sensor (CTECS) developed by the Aerospace Corporation. Precise 3-axis magnetic fields will be measured by the magnetometer provided by NASA Goddard Space Flight Center (GSFC). Brazilian scientists and
Plasma Density:
Sweeping Impendence Probe
Ion Drift and Temperature:
Ion Velocity Meter
Scintillations and TEC:
CTECS
Floating Potentials:
Electric Field Probe (Sensor 2)
Floating Potential:
Electric Field Probe (Sensor 1)
Plasma Density and Temperature:
Langmuir Probe
Magnetic Field:
colleagues will provide ground-based observations of the ionosphere, including radio sounding and airglow optical imaging.
By analyzing these data together in a holistic manner, the SPORT Science team will discern the variations in electron densities in the ionosphere. The spatial and temporal scales under investigation are appropriate for studying the effects of irregularities specifically affecting VHF and L-band radio signals. These signals are particularly susceptible to scintillation during solar and/or geomagnetic activity. This investigation will study the statistical distribution of equatorial plasma bubbles as a function of longitude and local time, in addition to seeking the precursor trigger mechanisms for such bubbles.
When developing a satellite with multiple science instruments from multiple institutions, it is imperative that the team tests the communication between the three satellite on-board processors (Payload Data Handling (PDH), Spacecraft Command and Data Handling (CD&H), the Data Storage Unit (DSU)), and all of the instruments. This was accomplished for the SPORT mission during 2019. The so-called ‘Flatsat’ configuration was comprised of the spacecraft processors (avionics) and all of the instruments (note that the IVM consisted of a flight emulator, all other instruments were actual flight-like components) connected together on a clean bench. Command and data handling was tested for all instruments in two campaigns—one where each instrument was tested individually, and the other where all instruments were tested together. Initially, all systems were tested successfully with one exception—the PDH processor failed to accommodate the large volume and rate of data from the CTECS instrument. The team was able to adequately capture the CTECS data by directly linking the instrument with the DSU processor instead of the PDH. Now that the Flatsat testing is complete, the SPORT satellite is considered to be a developmental model.
In August of 2019, the SPORT team underwent a rigorous critical design review. The independent review team did not identify any major findings (i.e., major weaknesses) of the mission development, but it did provide recommendations, concerns, and comments. For example, the attitude
determination and control system (ADCS) modeling and simulation routines need to be updated to incorporate potential feedback of the flexible structures onto the spacecraft body while in orbit. Additionally, it was recommended that the SPORT team explore options for post-processing of star- tracker data on the ground to improve the precision of the attitude determination data. Finally, some recommendations for improvement on the thermal modeling, especially for best- and worst-case scenarios, were provided. These and additional post-CDR activities will be the focus of the work in 2020 as the SPORT team works toward a delivery in early 2021.
SUMMARY
SPORT is a joint U.S.-Brazilian CubeSat mission to investigate equatorial ionospheric plasma bubbles and associated scintillation on radio signals known to cause outages in communication and navigation systems. By employing the state-of-the-art space weather instruments in space as well on the ground, the SPORT team will use observational data with expert models to advance the ability to forecast space weather effects on these systems. With a 2021 launch, the mission will demonstrate the ability to use a lost-cost mission to do world-class science.
PRINCIPAL INVESTIGATOR: James Spann
DEPUTY PRINCIPAL INVESTIGATOR: Charles Swenson,
Utah State University
PROJECT MANAGER: Shelia Nash-Stevenson
PARTNERS: Instituto Tecnológico de Aeronáutica; Instituto
Nacional de Pesquisas Espaciais, Utah State University, University of Texas at Dallas, University of Alabama at Huntsville, The Aerospace Corporation, and GSFC.