Gregory P. GinetSpace Vehicles Directorate

Air Force Research Laboratory

Demonstrations & ScienceExperiment (DSX)

05 Mar 2009

DSXOutline

• Introduction

• Satellite & Payloads

• Orbital Coverage

• CONOPS

• Status & Summary

DSXMission Objectives

• Nominal orbit: 6000 k x 12000 k,125 deg incl, launch ~ 2012

• Three science experiments:1) Wave-particle interactions (WPIx)

•Determine efficiency of injecting VLF into space plasmas in situ

•Determine global distribution of natural & man-made ELF-VLF waves

•Characterize and quantify wave-particle interactions

2) Space weather (SWx)• Map MEO radiation & plasma environment

• Diagnose in-situ environment for wave generation experiments

3) Space environment effects (SFx)•Quantify effects of MEO environment on new technologies

•Determine physical mechanisms responsible for material breakdown

ELF/VLF Waves Control Particle Lifetimes

L shell = distance/RE

Particles mirroring below

100 km are “lost”

Electromagnetic

waves

Particle pitch-angle

Electromagnetic waves in the Very Low Frequency (VLF) range (3-30 kHz) scatter and accelerate radiation belt electrons through cyclotron resonance interactions

DSXWave-Particle Interactions

Waves from CRRES (1990)

Diffusion coefficient along

field lines

Quantitative understanding of VLF wave power distribution & resultant wave-particle interactions is crucial for radiation belt specification & forecasting

Quantitative understanding of VLF wave power distribution & resultant wave-particle interactions is crucial for radiation belt specification & forecasting

Wave power in the magnetosphere

Diffusion coefficients

along field lines

Particle lifetime along field lines

(approximate 1D solution)

jXX

iijX

tXfD

X=

t

tXfji

,1,

Full 3D global, time dependent particle distributions

Xi = (L, E, )

Wave-particle resonance condition

Diffusion coefficients = sum over resonancesComplex dependence on energy,

frequency, and pitch angle

Distribution of Resonant Wave Vectors

DSXSpace Weather Forecasting

Transmitters

Natural VLF

VLF antennas in plasma are very different than in vacuo:• Sheaths form around elements due to free electrons & ions

• High-power levels can heat local plasmas

• Far-field radiation a result of complex current distribution

Several modeling approaches being taken • Analytic impendence theory with 1-D sheath & empirical tuning (UM/Lowell)

• Dynamic 3-D “electrostatic” simulations with NASCAP-2K (SAIC)

• 3-D FDFD electromagnetic simulations with PML’s (Stanford)

• Linear-response cold plasma theory in far-field (Stanford, UM/Lowell, AFRL, etc.)

Validation with LAPD in laboratory plasmas (UCLA)

3-D electrostatic antenna simulation

(NASCAP-2k, SAIC)

VLF loop antenna

+300

+10

-10000

-10

Electrostatic potential (Volts)

3-D FDFD antenna simulation (Stanford)

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+

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Iantennaantenna

Isheathsheath

1-D equivalent circuit

(UMass/Lowell)

Current models predict wildly different scaling of power output with frequency & antenna length - DSX will provide validation

Current models predict wildly different scaling of power output with frequency & antenna length - DSX will provide validation

DSXVLF Injection Efficiency

DSXVLF Injection Efficiency

For MEO orbit (L=2.2), #years to reach 100 kRad:• Quiet conditions (NASA AP8, AE8) : 88 yrs• Active conditions (CRRES active) : 1.1 yrs

AE8 & AP8 under estimate the dose for 0.23’’ shielding

(>2.5 MeV e ; >135 MeV p)

L (RE)

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HEO dose measurements show that current radiation models (AE8 & AP8) over estimate the dose for thinner shielding

J. Fennell, SEEWG 2003

Example: Highly Elliptic Orbit (HEO) Example: Medium-Earth Orbit (MEO)

DSXCurrent Standard Models (AE8 & AP8)

Model differences depend on energy:

L (RE) L (RE) L (RE) L (RE)

Om

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/(cm

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DSXWhere is the 20 dB?

Abel & Thorne (1998) Starks, et al. (2008)

Ground transmitter VLF needed in the inner magnetosphere… but where is it?Ground transmitter VLF needed in the inner magnetosphere… but where is it?

For Official Use Only

Wave-Particle Interactions (WPIx)– VLF transmitter & receivers

– Loss cone imager

Space Weather (SWx)– 5 particle & plasma detectors

Space Environmental Effects (SFx)– NASA Space Environment Testbed

– AFRL effects experiment

40 m

40 m

8 m

8 m

FSH

HST

Y-Axis Booms• VLF E-field Tx/Rx

Z-Axis Booms• VLF E-field Rx

AC Magnetometer– Tri-axial search coils

DC Vector Magnetometer

Loss Cone Imager - High Sensitivity Telescope - Fixed Sensor Head

VLF Transmitter & Receivers- Broadband receiver- Transmitter & tuning unit

Radiation Belt RemediationDSX Satellite

Radiation Belt RemediationDSX Satellite

ESPA Ring• Interfaces between EELV & satellite

10

• Receiver (Stanford, Lockheed-Martin, NASA/Goddard):– Three search coil magnetometers (3 B components)

– Two dipole antennas (2 E components)

– Frequency range: 100 – 50 kHz

– Sensitivity 1.0e-16 V2/m2/Hz (E) & 1.0e-11 nT2/Hz (B)

• Transmitter (UMass Lowell, SWRI, Lockheed-Martin):– 3 – 50 kHz at up to 500 W (900 W at end of life)

– 50 – 750 kHz at 1W (local electron density)

• Loss Cone Imager (Boston University, AFRL)– High Sensitivity Telescope (HST): measures 100 – 500 keV e- with 0.1

cm2-str geometric factor within 6.5 deg of loss cone

– Fixed Sensor Heads (FSH): 130 deg x 10 deg of pitch angle distribution for 50 – 700 keV electrons every 167 msec

• Vector Magnetometer (UCLA)– 0 – 8 Hz three-axis measurement at ±0.1 nT accuracy

Vector magnetometer

Loss Cone Imager HST & FSH

Transmitter control & tuning units

Broadband receiver & tri-axial search coils

14 May 2007NASA GSFC 14 May 200714 May 2007NASA GSFC

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DSXWave-Particle Interactions Payload

WPIx instruments designed to measure efficiency of VLF injection, propagation and wave-particle interactions in a

controlled manner

WPIx instruments designed to measure efficiency of VLF injection, propagation and wave-particle interactions in a

controlled manner

11

LEESA

LIPS

HIPS

HEPS

0.0001 0.001 0.01 0.1 1 10 100 1000

Energy (MeV)

LEESA

LIPS

HIPS

Protons

Electrons

LEESA

LIPS

HIPS

HEPS

0.0001 0.001 0.01 0.1 1 10 100 1000

Energy (MeV)

LEESA

LIPS

HIPS

Protons

ElectronsCEASE

CEASE

LCI-FSH

DSX Space Weather Payload

CEASE - Compact Environment Anomaly Sensor (Amptek, AFRL)LEESA - Low Energy Electrostatic Analyzer (AFRL)LIPS - Low Energy Imaging Particle Spectrometer (PSI)HIPS - High Energy Imaging Particle Spectrometer (PSI)HEPS - High Energy Particle Sensor (Amptek, ATC)

Comprehensive SWx sensor suite will map full range of MEO space particle hazards

Comprehensive SWx sensor suite will map full range of MEO space particle hazards

HEPS

CEASE

HIPS

LIPS

LEESA

Radiation beltsRing current & auroraPlasmasphere

Energy (MeV)

HEPS

CREDANCE

ELDR

S

DIM

E

CO

TS-2

DIM

E

SET Carrier (NASA-GSFC)

DSXSpace Weather Effects Payload

NASA Space Environment Testbed (SET)• CREDANCE (QinetiQ)

– Cosmic Radiation Environment Dosimetry and Charging Experiment

• DIME (Clemson Univ)– Dosimetry Intercomparison and Miniaturization

• ELDRS (Arizona State)– Development of space-based test platform for the

characterization of proton effects and Enhanced Low Dose Rate Sensitivity (ELDRS) in bipolar junction transistors

• COTS-2 (CNES and NASA)– Validation of single event effects mitigation via fault

tolerant methodology

AFRL/PRS “COTS” sensors

Radiometers

Photometers

1”

Objective: directly measure changes in • Optical transmission, • Thermal absorption• Thermal emission

due to MEO radiation environment

SFx experiments will quantify MEO environment effects on advanced spacecraft technologies & determine basic physics of breakdown

SFx experiments will quantify MEO environment effects on advanced spacecraft technologies & determine basic physics of breakdown

DSXOrbital Coverage

6000 x 12000 km, 120 deg inclination

Equatorial pitch-angles vs. L*

DSXPlasma Environment

Characteristic frequencies vs. radius

Plasma density vs. radius

DSXEnergetic Particle Environment

> 2 MeV electrons vs. radius> 36 MeV protons vs. radius

January August

Satellite-Derived (LIS/OTD) Monthly Global Lightning Climatology (1995 – 2003)

DSXLightning Climatology

• Monthly global lightning climatology at 0.5 deg resolution has been developed from LIS/OTD satellite data for DSX mission planning– Model captures both cloud-to-cloud and cloud-to-ground strokes

• Applications to map DSX field line footprints onto Earth’s surface being developed– “Lightning index” will computed for each ephemeris point used in mission planning

Flashes Km-2 Year

• Three-axis stabilized satellite with ~ 5 hour orbit

• SWx and SFx payloads operate continuously

• Momentum and power restrictions limit WPIx operations– Field line tracking 1-2 hours/orbit

– TNT VLF high power transmission, 0.5 – 1 hour/orbit at 5 kV

– TNT is in passive or relaxation sounding when not in high-power VLF transmission

– BBR survey, LEESA, VMAG and LCI FSH are on continuously

– LCI HST only on in field like tracking mode

– LEESA high data rate mode for VLF transmission

– End-of-life “Hail Mary” mode for TNT VLF transmissions at 10 kV

• Detailed CONOPS planning underway – MOC-POC-Science Data Center structure

– Collaboration opportunities with other assets being identified

DSXCONOPS Overview

DSXCollaboration Opportunities – Space 1

• Cassiope/Enhanced Polar Outflow Probe (E-PoP), CSA, CRC (James), NRL (Siefring, Bernhardt)– 300 x 1500 km, polar inclination, launch Sep 2009

– Radio Receiver Instrument (RRI), ELF-VLF 10 Hz -30 kHz, two-axis E-field

– Fast Auroal Imager (FFI), ~ 1 MeV electrons

• Radiation Belt Storm Probes (RBSP), NASA– 2 satellites in GTO, < 18 deg incl, launch no earlier than fall 2011

– Electric and Magnetic Field Instrument Suite and Integrated Science Suite (EMFISIS, Univ. of Iowa, Kletzing), 3 axis B-field, 2 axis E-field 10 Hz – 12 kHz (1 channel E-field 10 kHz – 400 kHz)

– Magnetic Electron-Ion Spectrometer (MagEIS, BU & Aerospace, Spence & Blake), 40 keV – 10 MeV electrons

– Relativistic Electron-Proton Telescope (REPT, BU & Univ. of Colorado, Spence & Baker), 2 MeV – 10 MeV electrons

– RBSP Ion Composition Explorer (RBSPICE, NJIT, Lanzerotti), 25 keV – 500 keV electrons

DSXCollaboration Opportunities –Space 2

• DEMETER, CNES, Stanford Co-PI (Inan)– 670 km, 98.3 deg incl, ongoing mission, will it last to 2012?

– IMSC, 3 component B-field, ~ 2 Hz – 20 kHz

– IDP, electron detector, ~ 50 keV – 500 keV

• TRIANA, CNES, Stanford Co-PI (Inan), follow on to DEMETER– 700 km, polar, launch 2011

– IMM-MF, B-field 3 component, ~2 Hz – 20 kHz, 1 component 10 kHz – 1MHz

– IDEE, electron detectors, 70 keV – 4 MeV

• ORBITALS, CSA, Univ. of Calgary (Mann), Univ. of Colorado (Baker)– SCM, B-field up to 20 kHz

– EPS, electrons 25 keV – 12 MeV

DSXCollaboration Opportunities – Ground

• High-Frequency Active Auroral Research Program (HAARP, AFRL)– Electrojet-modulated VLF antenna at L ~ 4.8 with extensive frequency &

mode control

• Navy VLF transmitters, RBR TIPER program (AFRL, DARPA & Stanford)– NAA at Cutler, ME, L ~ 3.0, 24 kHz, 885 kW, began keying in Jun 2008

– NWC at Churchill, Australia, L ~ 1.3, 21 kHz, 1 MW, begin keying ?

DSXStatus & Summary

• System CDR completed (May 2008)

• #1 in 2008 DoD SERB (Nov 2008)

• Payloads currently being delivered to AFRL/RV at Kirtland AFB

• AI&T to be completed by Apr 2010

• DSX Science Team Meeting, 15-18 Sep 2009, Lake Arrowhead

• Negotiations underway with STP for manifest as secondary payload on DMSP F-19 with launch in Oct 2012

DSXNew Technologies to be Space Qualified

• BBR: µLNA and µADC VLF receiver chips• LCI: RENA particle counting chip• TATU: Adaptive tuning for optimizing VLF TX• Y-Antenna: graphite epoxy material, largest

compaction ratio (1:100) and best mass efficiency (35 g/m) flown to date

• ESPA ring integral to host s/c bus structure• Soft-Ride Vibration Isolation – integral to s/c, not in

launch stack

Task Name

Pre-AI&T GSE (AFRL/RVE)

Mechanical GSE Development

AM Integration Stand

PM Integration Stand

Electrical GSE Development

Umbilical Rack Development

AI&T (AFRL/RVE)

Avionic Module (AM) Testing

Payload Module (PM) Integration

AM & PM Environmental Testing

ESPA Integration

System Level Testing

Compatibility Testing

SC Environmentals

SC Storage 6/28

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug SepQ1 '09 Q2 '09 Q3 '09 Q4 '09 Q1 '10 Q2 '10 Q3 '10

Hardware Delivery WindowAUG‘08 JUL’09

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Payload Module

Bus Deliveries

PL Deliveries

Critical Path

DSX AI&T (AFRL)

Last update 1/22/09

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DSXSchedule of Milestones

PROPULSIONDIRECTORATE

Space EnvironmentalEffects

VLF Wave-Particle Interaction VLF Wave-Particle Interaction ExperimentExperiment

Space WeatherSpace WeatherExperimentsExperiments

Spacecraft BusSpacecraft Bus

Launch Segment

Program OfficeProgram OfficeSystems EngineeringSystems EngineeringIntegration and TestIntegration and Test

DSXThe Team