Transcript DSX Briefing

Demonstrations & Science
Experiment (DSX)
05 Mar 2009
Gregory P. Ginet
Space Vehicles Directorate
Air Force Research Laboratory
DSX
Outline
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Introduction
Satellite & Payloads
Orbital Coverage
CONOPS
Status & Summary
DSX
Mission 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
DSX
Wave-Particle Interactions
Particles mirroring below
100 km are “lost”
Particle pitch-angle
ELF/VLF Waves Control Particle Lifetimes
Electromagnetic
waves
L shell = distance/RE
Electromagnetic waves in the Very Low
Frequency (VLF) range (3-30 kHz) scatter
and accelerate radiation belt electrons
through cyclotron resonance interactions
Waves from CRRES (1990)
DSX
Space Weather Forecasting
Transmitters
Diffusion coefficient
along field lines
 
Natural VLF
Wave power in the
magnetosphere
Diffusion coefficients
along field lines
Distribution of Resonant
Wave Vectors
Wave-particle resonance condition
Diffusion coefficients = sum over resonances
Particle lifetime along field lines
(approximate 1D solution)
Complex dependence on energy,
frequency, and pitch angle

 f X ,t 1
=
t


ij
 

 
 f X ,t
 D X i X j
 X i 
Xj

Full 3D global, time dependent
particle distributions
Xi = (L, E,  )
Quantitative understanding
of VLF wave power
distribution & resultant
wave-particle interactions is
crucial for radiation belt
specification & forecasting
DSX
VLF Injection Efficiency
Isheath
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
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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.)
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Iantenna
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1-D equivalent circuit
(UMass/Lowell)
Validation with LAPD in laboratory plasmas (UCLA)
Electrostatic potential (Volts)
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+10
-10
VLF loop antenna
-10000
3-D electrostatic antenna simulation
(NASCAP-2k, SAIC)
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0>
Several modeling approaches being taken
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3-D FDFD antenna simulation (Stanford)
Current models predict wildly different scaling of power output with
frequency & antenna length - DSX will provide validation
DSX
Current Standard Models (AE8 & AP8)
Example: Highly Elliptic Orbit (HEO)
Example: Medium-Earth Orbit (MEO)
J. Fennell,
SEEWG 2003
Behind 0.23” Al
Dose Rate (Rads/s)
(>2.5 MeV e ; >135 MeV p)
L (RE)
HEO dose measurements show that current radiation
models (AE8 & AP8) over estimate the dose for
thinner shielding
Omni. Flux (#/(cm2 s Mev)
Model differences depend on energy:
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
L (RE)
L (RE)
L (RE)
L (RE)
DSX
Where is the 20 dB?
Starks, et al. (2008)
Abel & Thorne (1998)
≠
Ground transmitter VLF needed in the inner magnetosphere… but where is it?
Radiation Belt Remediation
DSX Satellite
AC Magnetometer
– Tri-axial search coils
For Official Use Only
Wave-Particle Interactions (WPIx)
– VLF transmitter & receivers
– Loss cone imager
Space Weather (SWx)
– 5 particle & plasma detectors
8m
Z-Axis Booms
• VLF E-field Rx
Space Environmental Effects (SFx)
– NASA Space Environment Testbed
– AFRL effects experiment
ESPA Ring
• Interfaces between EELV
& satellite
Loss Cone Imager
- High Sensitivity Telescope
- Fixed Sensor Head
Y-Axis Booms
VLF Transmitter & Receivers
- Broadband receiver
- Transmitter & tuning unit
• VLF E-field Tx/Rx
8m
DC Vector Magnetometer
DSX
Wave-Particle Interactions Payload
• Receiver (Stanford, Lockheed-Martin, NASA/Goddard):
– Three search coil magnetometers (3 B components)
– Frequency range: 100 – 50 kHz
– Sensitivity 1.0e-16 V2/m2/Hz (E) & 1.0e-11 nT2/Hz (B)
Transmitter control & tuning units
amp
- Pre
- Ex
- Ey
- Bx
- By
- Bz
trol
- Con
– Two dipole antennas (2 E components)
• Transmitter (UMass Lowell, SWRI, Lockheed-Martin):
NASA GSFC
– 3 – 50 kHz at up to 500 W (900 W at end of life)
– 50 – 750 kHz at 1W (local electron density)
14 May 2007
Broadband receiver &
tri-axial search coils
• 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
Loss Cone Imager
HST & FSH
• Vector Magnetometer (UCLA)
– 0 – 8 Hz three-axis measurement at ±0.1 nT accuracy
WPIx instruments designed to measure efficiency of VLF
injection, propagation and wave-particle interactions in a
controlled manner
Vector magnetometer
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DSX
Space Weather Payload
Plasmasphere
Radiation belts
Ring current & aurora
Protons
HIPS
HEPS
LIPS
HEPS
LEESA
CEASE
CEASE
Electrons
HIPS
LCI-FSH
LIPS
HIPS
HEPS
LEESA
0.0001
0.001
0.01
0.1
1
10
100
1000
CEASE
Energy (MeV)
Energy
(MeV)Sensor (Amptek, AFRL)
CEASE - Compact Environment
Anomaly
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
LIPS
LEESA
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DSX
Space Weather Effects Payload
Photometers
CREDANCE
SET Carrier (NASA-GSFC)
1”
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
Radiometers
AFRL/PRS “COTS” sensors
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
DSX
Orbital Coverage
6000 x 12000 km,
120 deg inclination
Equatorial pitch-angles vs. L*
DSX
Plasma Environment
Plasma density vs. radius
Characteristic frequencies
vs. radius
DSX
Energetic Particle Environment
> 36 MeV protons vs. radius
> 2 MeV electrons vs. radius
DSX
Lightning Climatology
Satellite-Derived (LIS/OTD) Monthly Global Lightning Climatology
(1995 – 2003)
Flashes Km-2 Year
January
August
• 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
DSX
CONOPS Overview
• 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
DSX
Collaboration 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
DSX
Collaboration 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
DSX
Collaboration 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 ?
DSX
Status & Summary
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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
DSX
New Technologies to be Space Qualified
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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
DSX
Schedule of Milestones
Bus Deliveries
PL Deliveries
Critical Path
LCI
Y-Antenna
HIPS
WIPER
LIPS
CEASE
LEESA
ESPA
Payload Module
Separation System 06/02/10
SA
JUL’09
AM
Flt Battery
ECS
Z-Antenna
PM
VMAG
HEPS
Rad/Photom
Avionics Module
SET-1
AUG‘08 Hardware Delivery Window
TACSAT-3
DSX AI&T (AFRL)
Last update 1/22/09
DSX
The Team
Program Office
Systems Engineering
Integration and Test
Launch Segment
Spacecraft Bus
VLF Wave-Particle Interaction
Experiment
Space Environmental
Effects
PROPULSION
DIRECTORATE
Space Weather
Experiments