Gregory P. Ginet Space Vehicles Directorate Air Force Research Laboratory
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Transcript of Gregory P. Ginet Space Vehicles Directorate Air Force Research Laboratory
Gregory P. GinetSpace Vehicles Directorate
Air Force Research Laboratory
Demonstrations & ScienceExperiment (DSX)
05 Mar 2009
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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> 00 >
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)
Do
se
Ra
te (
Ra
ds
/s)
Beh
ind
0.2
3”
Al
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
ni.
Flu
x (#
/(cm
2 s
Mev
)
≠
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
-P
ream
p
-E
x
-E
y
-B
x
-B
y
-B
z
-C
ontr
ol
-P
ream
p
-E
x
-E
y
-B
x
-B
y
-B
z
-C
ontr
ol
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
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
AM
EC
S
HE
PS
Rad
/Ph
oto
mAvionics Module
SA
VM
AG
SE
T-1
CE
AS
E
LC
I
LE
ES
A
PM
Payload Module
Bus Deliveries
PL Deliveries
Critical Path
DSX AI&T (AFRL)
Last update 1/22/09
Flt
Ba
tte
ry
WIP
ER
ES
PA
LIP
S
Z-A
nte
nn
a
Sep
ara
tio
n S
ys
tem
06
/02
/10
Y-A
nte
nn
aH
IPS
TACSAT-3
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