Introduction to SBEM for Space Weather (2024-05-07).pdf

© The Aerospace Corporation, 2024

Introduction to Space Based Environmental

Monitoring (SBEM) for Space Weather

Mr. Jeff Cox

Dr. Paul R Straus

May 7, 2024

UNCLASSIFIED

UNCLASSIFIED

Distribution Statement A. Approved for public release: distribution unlimited.

Current JROCM 092-14 SBEM Category A Requirements Gaps Space weather requirements in BLACK text

Prioritized Parameters Resolution Accuracy Timeliness Refresh Rate

1. Cloud Characterization 1 km 10 min 4 hr

2. Theater Weather Imagery Sufficient to resolve clouds, fog, thunderstorms, sand & dust storms 15 min

4 hr (15 min desired)

3. Ocean Surface Vector Winds (OSVW) 25 km Speed ±2 m/s

Direction ±15º 3 hr 6 hr

4. Ionospheric Density 10 km ±10% or ±1 TEC (total electron content) unit 10 min 30 min

5. Snow Depth 25 km 10% 2 hr 24 hr

6. Soil Moisture (5 cm depth) 50 km 6% 2 hr 24 hr (early AM)

7. Equatorial (<30° latitude) Ionospheric

Scintillation 10 km

S4 (amplitude) 0.1 σϕ (phase) 0.1 radians 10 min 30 min

8. Tropical Cyclone Intensity 20 km 3 hr 6 hr

9. Sea Ice Characterization 20 km Distinguish first vs.

multi-year 24 hr

10. Auroral Characterization 10 min 10 min

11. Low Earth Orbit (LEO) Energetic

Charged Particle (ECP) Characterization Energy: >1 keV 4x (factor of 4) 2 hr

10 sec (sensor on spacecraft)

12. Electric Field 10 km ±3 mV/m 10 min 30 min

Space Weather Family of Systems

• What are the space weather sensing orbits? DoD is focused on near-earth orbits (NOAA/NASA cover

Lagrange points and off the Sun-Earth line). DoD relies on NOAA for solar wind in situ observations.

NOAA’s Space Weather Next – Notional Plan

Heavy reliance on “hosted” space weather sensors vs. dedicated observing satellites

Ionospheric Density

Ionospheric Vertical Structure & Applications

Two types of ionospheric applications: Trans-ionospheric & bottomside

• Higher frequency signals penetrate the ionosphere, but experience propagation delays and some signal path bending

• Characterized by total electron content (TEC) along path

• Lower frequency signals (e.g., HF Comms, Over-the-

Horizon Radars) bounce off the ionospheric “bottomside”

• Characterized by F- & E-region peak densities & heights

• The Earth’s ionosphere is created by partial ionization of the tenuous upper atmosphere by solar extreme & far ultraviolet (EUV/FUV) light

– At high latitudes energetic particle precipitation also contributes to the ionosphere

• It extends from ~80 to >1000 km altitude and is characterized by the electron density as a function of location

• Ionospheric densities are highest during the daytime and slowing decay at night

– Ionospheric effects, though reduced are still important at night

• Ionospheric densities vary substantially over the 11-year solar cycle

Bottomside Applications & Sporadic E Potential RO contributions

• Radio occultation is the only space-based technique that can provide insight into ionospheric bottomside structures, including sporadic-E layers, that can significantly impact over-the-horizon radar performance

Re ion

Re ion

E Re ion

E ectron density profi e s ip distance detection ran e radar tar et oca pea density in poradic E ayer ionosphere

E

Normal OTHR Operations with foF2 > fOTHR > foE

Impacted OTHR Operations with foE > foF2 (limited range)

Ionospheric Variability

• Besides the solar forcing, atmospheric and geomagnetic interactions cause additional ionospheric variability

– Geographic

– Seasonal

– Geomagnetic storms

• Variability time scales range from 10 minutes (high latitudes) to 1-3 hours

– Mid-latitudes are most stable

– Maximum densities occurs at low latitudes:

the Equatorial Ionization Anomaly (EIA)

WAM-IPE = Whole Atmosphere Model – Ionosphere Plasmasphere Electrodynamics (NOAA operational model)

Operational Ionospheric Specification “Food Chain”

Assimilative

Ionospheric

Model

3D Ionospheric

Specification Possible Data Sources

Ground-Based

Ionosondes

Dual-frequency GNSS receivers

Space-Based

Radio occultation

In-situ density sensor

Topside sounder

Far ultraviolet (FUV) limb/disk

Geostationary FUV

High-inclination FUV

Ground+Space combination

RF Beacon or DORIS

LEO

Ionospheric Corrections for Surveillance

Applications

• In contrast to some terrestrial and some space weather applications, certain ionospheric applications require near real time specification, not forecasting

• Current operational paradigm for such applications involves collection of ionospheric data & assimilation into a specification model

Prior Operational Sensors

DMSP

• DMSP F16-F19 incorporated several ionospheric sensors

– SSUSI: Special Sensor Ultraviolet Spectrographic Imager

– SSULI: Special Sensor Ultraviolet Limb Imager

– SSIES: Special Sensor Ions Electrons & Scintillation

• SSUSI & SSULI measured ionospheric airglow signals in the EUV/FUV to sense ionospheric properties

– Best observations on the nightside at low latitudes where the recombination of oxygen ions produces emissions at

135.6 nm that are proportional to the square of the electron density

– Dayside and high latitude airglow observations provided different information related to the upper atmosphere and aurora, but these are not assimilated into operational ionospheric models

• SSIES measured in-situ ionospheric density

• DMSP limitations

– Only 2 orbit planes of data: not enough to cover spatial variability of the ionosphere & typically near sunrise/sunset terminator due to tropospheric mission requirements – not optimal for EUV/FUV technique

– Poor data latency (up to 3 hours) reduced value of ionospheric data

Current Missions: The COSMIC-2 Partnership

Mission Objectives

– Provide radio occultation (RO) observations of terrestrial and space weather for operational & scientific use

– Provide ancillary space weather sensor data for operational & scientific use

US/Taiwan Partnership Responsibilities

NSPO (Taiwan)

– Spacecraft (SSTL subcontract)

– Spacecraft/sensor Integration & Test

– Mission Operation (satellite control: 1 ground station)

NOAA (United States)

– Lead US agency

– Nine ground stations

– RO sensor data processing (at UCAR)

USSF (United States)

– All sensors

– Launch

– Secondary sensor data processing

COSMIC-2 space segment:

6 equatorial orbit satellites

COSMIC-2 ground stations provide

30-minute median latency

Command & Control stations Telemetry Only stations

Although COSMIC-2 provides much more Ionospheric Density & Scintillation observations than DMSP, and at much lower latencies, it does not provide global coverage for Gap 4

• Radio Occultation (RO) sensors are special purpose GNSS receivers flown in low-Earth orbits w/ limb-facing antennae

• Observations of GNSS carrier phase, pseudorange and signal strength can be used to determine both ionospheric and tropospheric information

– Total Electron Content (TEC) – both overhead & on limb

– Ionospheric scintillation

Radio Occultation Overview

– Lower atmospheric temperature/moisture

Ionospheric Density (Gap 4): Seeking Improved Coverage/Refresh

RO Concept

TEC Climatology

TEC w/ COSMIC-2 RO

TEC Error Maps

NASA GOLD

Sample FUV

Data

Climatology w/ GOLD

• Future Gap 4 architectures can substantially out-perform heritage

(e.g., DMSP) by exploiting sensor types that can be proliferated on LEO constellations or that provide continuous broad-area coverage from high altitude orbits

– Low data latency is also an important requirement

• Examples: Radio Occultation (LEO) & FUV Imager (GEO/HEO)

• These techniques have been demonstrated to provide data quantities at low latency sufficient to significantly impact ionospheric specification accuracies in near-realtime

• Hosted payload & commercial data purchase options are possibilities

Equatorial Ionospheric Scintillation

What Is Ionospheric Scintillation?

• Ionospheric instabi ities enerate turbu ent structures (“ionospheric bubb es”)

• When trans-ionospheric signals (e.g., satellite C2, SATCOM, GPS

NAV) pass through these small-scale structures, the RF link becomes scintillated, leading to lost comm and possible navigation errors

– Predominately occurs at low-latitudes at night

– High-latitude scintillation due to auroral instabilities can also be significant

(included in Auroral Characterization Gap)

• RFI attribution and scintillation impact predictions for SATCOM and

GPS are high priorities for Space domain awareness Environmental

Toolkit for Defense (SET4D)

• Legacy scintillation capability is very poor

– Driven by limited ground-based data and climatology

– DMSP SSIES sensor measured plasma fluctuations related to scintillation, but at high altitude (850 km) – far above F-region peak most of the time

Incoherent Scatter Radar Observations of

Ionospheric Irregularities that Cause Scintillation

Low Latitude Scintillation Region

Instability Development Timescale is 15-30 Minutes

Equatorial Scintillation Development Irregularity regions form due to a nightside plasma instability

Scintillation strongest in regions of high background density

Max Apex Altitude

Final Irregularity Extent

Initial Irregularity Region

Uplift

Poleward Expansion

Note: Climatological ionospheric density depicted for reference

Scintillation Variability (Example: Far East Longitude Sector)

Day 79 (20Mar)

400 MHz

SSN 200

Kp=3

20.7 LT

23.5° Lat

120.8° Lon

95th Percentile

50th Percentile

95th Percentile

50th Percentile

Day 79 (20Mar)

400 MHz

SSN 200

Kp=3

20.7 LT

120.8° Lon

>4 dB fades below 28.6°/

27.2° latitude

>4 dB fades below 39.7°/

39.4° latitude

RED:

SSN=120

Transmitter latitude varies

Receiver fixed @23.5°

95th Percentile

50th Percentile

Day 79 (20Mar)

SSN 200

Kp=3

20.7 LT

23.5° Lat

120.8° Lon

RED:

SSN=120

RED:

SSN=120

Day 262 (19Sep)Day 79 (20Mar)

Variability Factors

• Location (lat/lon)

• Local time

• Season

• Ionospheric density

• Geomagnetic activity

• Signal frequency

• RF link geometry

COSMIC-2: Scintillation Detection Using Radio Occultation “A C ear Maps” & “Bubb e Maps”

• evera in pioneerin wor done but the Air orce Research aboratory’s Communications Navi ation

Outage Forecast System (C/NOFS) satellite project, new techniques for scintillation monitoring have been developed by SSC under COSMIC-2

• All Clear Maps: indicates when scintillation is not a factor to consider in operational RFI attribution

• Bubble Maps: indicates regions where scintillation-causing instabilities are present

• Va idation has estab ished that “A C ear” specification is ood >97% of the time

• Initial version of product (currently operational) applies to ground-based UHF users

• Updated product will extend All Clear to L-band frequencies

Bubble MapAll Clear Map

Equatorial Ionospheric Scintillation (Gap 7): Sustaining & Improving

COSMIC-2 Performance

• Although All Clear & Bubble Map are important new operational capabilities, improvements are desirable

• COSMIC-2’s 30-minute median data latency degrades NRT coverage/refresh

• Higher data densities (more occultations) might enable a 2D (latitude/longitude) specification of irregularity regions vs the current 1D (longitude only) specification

• Note that since Gap 7 is equatorial in nature, low inclination LEO systems, such as COSMIC-2, will always have an efficiency advantage over high inclination systems because they spend more time at low latitudes

• Any alternate (non-RO) sensing technologies that can be shown to provide useful characterization of the low latitude scintillation environment will also be considered

Auroral Characterization

Why is Aurora Characterization Important?

• Aurora phenomena can cause impacts on LEO satellites (surface charging), ground-based radars

(clutter), high frequency (HF) communications/OTH radars, and SATCOM

• Aurora intensities and locations are dynamic with rapid changes in precipitating particles and the ionospheric response

– High altitude imagery provides a persistent vantage point for measuring these dynamic changes

– pLEO satellite constellations with rapid refresh/coverage are needed for a disaggregated approach

NASA/IMAGE FUV imagery video from HEO orbit

Radar Auroral Clutter

a) Radar fan defines the area where the targets and aurora can be seen

b) Radar propa ation path must be perpendicu ar to ma netic fie d, aspect an e ≤ 4

(defines the potential clutter zone – blue oval)

c) Auroral energy must be above threshold level to impact the frequency of interest

(defined by the auroral intensity – yellow/orange shaded area)

d) Auroral electron density irregularities must be present within the radar fan and potential clutter zone

Auroral Sensing/Modeling Techniques

• LEO Energetic Charged Particles

– High inclination LEO measurements identify auroral boundaries, particle precipitation

– DMSP SSJ4/5 (Precipitating

Particle Spectrometer) made electron/proton measurements for decades

– Empirical models used to specify the equatorward boundary, oval extent, and flux distribution

(Hardy)

• Geomagnetic Field (ground-based and space-based)

– Ground-based magnetometers measure the deviations in the geomagnetic field

– Field-Aligned Current (FAC) Maps from Active Magnetosphere and

Planetary Electrodynamics

Response Experiment (AMPERE) magnetometers on Iridium-Next

• Solar Wind Drivers (velocity, density and magnetic field)

– Empirical models of aurora parameterized by solar wind driving (Newell coupling function)

– OVATION-Prime

(Oval Variation, Assessment, Tracking, Intensity, and

Online Nowcasting – Prime)

• Far Ultra-violet Imagery

– LBH (N2) emission band (140-150

nm) shows the diffuse and discrete auroral arcs

– DMSP/SSUSI (Ultraviolet

Spectrographic Imager)

DMSP/SSJ - particles

DMSP/SSUSI – FUVOVATION-Prime – solar wind

AMPERE – FAC

LEO Energetic Charged Particles

Why are ECP Data Important?

• ECP observations are critical to Space Domain Awareness (SDA) in the contested space environment of today and into the future

• ECP observations and anomaly assessment tools are key enablers of the Space Warfighting Construct of

USSF Space Operations Command (SpOC)

– Must answer the SatOps Question: Is the environment impacting my spacecraft? Can you rule out space weather and focus on adversary threats?

Charged particle threat is significantly different across different energies and particles

What are the satellite hazards from ECP?

Four satellite anomaly types caused by energetic charged particles

• Event Total Dose (DOSE) normally organized into inner and outer belt separated by a slot. Inner belt dominated by protons; outer belt dominated by electrons. Damage accumulates over entire mission through ionizing and non-ionizing mechanisms. High energy protons (~2-20 MeV)

• Single Event Effects (SEE) tend to occur in the inner (proton) belt and at higher L shells when a solar particle event (SEP) is in progress. Galactic Cosmic Rays (GCR) also cause SEE at all orbits. High energy protons (~10-100 MeV)

• Internal electrostatic discharges (ESD) occur over a broad range of L values corresponding to the outer belt, when penetrating electron fluxes are high over extended periods of time. High energy electrons (~0.1-5 MeV)

• Surface ESD tends to occur when the spacecraft or surface potential is elevated: at 2000-0800 local time in the plasma sheet and in regions of intense field-aligned currents, e.g., auroral arcs. Low energy electrons (~0.1-40 keV)

H E

O -2

C h a rg in g E v e n ts

L ~ Equatorial Radial Distance (RE)

HEO

MEO

GEO

C R

R E

S M

E P

-S E

U A n o m a lie s

C R

R E

S V

T C

W A n o m a lie s

Inner

Belt

Slot

Outer

Belt

1 2 3 4 5 6 7 8

SEUs

Internal

Charging

Surface

Charging

(Radiation dose behind 82.5 mils Al)

Plasma

Sheet

Magnetic Latitude in LEO (deg) 0 45 55 60 63 66 68 69

On-board Sensor vs. Neighborhood Watch

• ecA James memo on 17 Mar 2015 stated, “directin each U A sate ite pro ram office to p an for and inte rate Ener etic Char ed Partic e (ECP) sensors on a new sate ites…”

– Fly in situ sensors to solve the ECP anomaly attribution question

– Small Size, Weight, and Power (SWaP) sensors have been designed and validated on orbit (Aerospace design –

ECP-Lite, AFRL design – Compact Environmental Anomaly Sensor [CEASE-III])

– Predates the proliferated Low Earth Orbit (pLEO) and small satellite surge (not practical to put CEASE-III on every pLEO smallSat mega-constellation satellite)

• “Nei hborhood Watch” paradi m (or “Weather” paradi m) is to co ect enou h ECP data from a variety of orbits to characterize the satellite anomaly threat from charged particles, everywhere NSS satellite systems operate

– Need representative data and/or energetic charge particle models to be able to characterize ECP flux in NSS satellite systems orbits

– Presently, this paradigm is only known to apply to high energy hazards, not surface charging

– LEO ECP data can be used to characterize high energy hazard at higher altitudes

– Must be used to attribute ECP hazards on satellites without in situ sensors (blue, grey, and red systems)

Using LEO ECP observations for high altitude specifications

• ECP motion is constrained by the oca ma netic fie d (Earth’s eoma netic fie d)

– Gyration around the field lines, bounce between the North and South magnetic poles, and longitudinal drift

• 2nd Adiabatic Invariant: bounce motion of particle between the North and South magnetic poles is key

• L-shell (invariant magnetic latitude)

𝐿 = 𝑅

𝑅𝐸 cos 𝑀𝐿𝐴𝑇 2 L=1 at surface, L=6.6 at GEO

– Represents the magnetic flux tube that has the same magnetic field and particle population

• An observation at on location of L=X, is the same at another location where L=X

• Hi h inc ination EO sate ites cross “a ” -shells and LEO ECP measurements can be mapped up the field lines to specify the ECP flux at

MEO, HEO, and GEO altitudes

- REACH meets this need today (replacement TBD)

Questions?

Electric Fields

Bubble Map Summary

COSMIC-2 advances in RO scintillation geolocation techniques provide the operational community with an unprecedented ability to monitor equatorial ionospheric scintillation in NRT

SSUSI Scan Geometry

GUVI Nightside 135.6 nm Disk Data February 1, 2002

GUVI Limb Profiles February 1, 2002