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Demonstrations & Science Experiment (DSX) 05 Mar 2009. Gregory P. Ginet Space Vehicles Directorate Air Force Research Laboratory. DSX Outline. Introduction Satellite & Payloads Orbital Coverage CONOPS Status & Summary. DSX Mission Objectives.

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slide1

Demonstrations & ScienceExperiment (DSX)

05 Mar 2009

Gregory P. Ginet

Space Vehicles Directorate

Air Force Research Laboratory

dsx outline
DSXOutline
  • Introduction
  • Satellite & Payloads
  • Orbital Coverage
  • CONOPS
  • Status & Summary
dsx mission objectives
DSXMission Objectives
  • Nominal orbit: 6000 k x 12000 k,125 deg incl, launch ~ 2012
  • Three science experiments:
    • 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
    • Space weather (SWx)
      • Map MEO radiation & plasma environment
      • Diagnose in-situ environment for wave generation experiments
    • Space environment effects (SFx)
      • Quantify effects of MEO environment on new technologies
      • Determine physical mechanisms responsible for material breakdown
dsx wave particle interactions
DSXWave-Particle Interactions

ELF/VLF Waves Control Particle Lifetimes

L shell = distance/RE

Particles mirroring below

100 km are “lost”

Particle pitch-angle

Electromagnetic

waves

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)

slide5

DSXSpace Weather Forecasting

Transmitters

Particle lifetime along field lines

(approximate 1D solution)

Diffusion coefficient along field lines

Natural VLF

Wave power in the magnetosphere

Diffusion coefficients

along field lines

Full 3D global, time dependent particle distributions

Xi = (L, E,  )

Distribution of Resonant Wave Vectors

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

Wave-particle resonance condition

Complex dependence on energy, frequency, and pitch angle

Diffusion coefficients = sum over resonances

slide6

DSXVLF Injection Efficiency

Isheath

+

-

-

-

-

+

+

-

+

-

-

+

> 0

0 >

-

-

-

Iantenna

+

-

+

+

+

Electrostatic potential (Volts)

+300

+10

-10

VLF loop antenna

-10000

  • 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 FDFD antenna simulation (Stanford)

3-D electrostatic antenna simulation

(NASCAP-2k, SAIC)

1-D equivalent circuit

(UMass/Lowell)

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

slide7

DSXCurrent Standard Models (AE8 & AP8)

Example: Medium-Earth Orbit (MEO)

Example: Highly Elliptic Orbit (HEO)

(>2.5 MeV e ; >135 MeV p)

Dose Rate (Rads/s)

Behind 0.23” Al

J. Fennell,

SEEWG 2003

L (RE)

  • 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

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

Model differences depend on energy:

Omni. Flux (#/(cm2 s Mev)

L (RE)

L (RE)

L (RE)

L (RE)

slide8

DSXWhere is the 20 dB?

Starks, et al. (2008)

Abel & Thorne (1998)

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

slide9

40 m

40 m

Radiation Belt RemediationDSX Satellite

  • 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
  • AC Magnetometer
    • Tri-axial search coils

FSH

8 m

  • Z-Axis Booms
  • VLF E-field Rx

HST

  • ESPA Ring
    • Interfaces between EELV & satellite

Loss Cone Imager

- High Sensitivity Telescope

- Fixed Sensor Head

  • VLF Transmitter & Receivers
    • Broadband receiver
    • Transmitter & tuning unit
  • Y-Axis Booms
  • VLF E-field Tx/Rx

8 m

DC Vector Magnetometer

slide10

DSXWave-Particle Interactions Payload

  • 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

Transmitter control & tuning units

Broadband receiver & tri-axial search coils

Loss Cone Imager HST & FSH

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

Vector magnetometer

slide11

DSX Space Weather Payload

Plasmasphere

Radiation belts

Ring current & aurora

HEPS

CEASE

CEASE

LCI-FSH

HIPS

HEPS

CEASE

Energy (MeV)

  • 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)

LIPS

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

LEESA

slide12

DSXSpace Weather Effects Payload

Photometers

ELDRS

COTS-2

CREDANCE

DIME

DIME

SET Carrier (NASA-GSFC)

  • 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

1”

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 environmenteffects on advanced spacecraft technologies& determine basic physics of breakdown

slide13

DSXOrbital Coverage

6000 x 12000 km,

120 deg inclination

Equatorial pitch-angles vs. L*

slide14

DSXPlasma Environment

Characteristic frequencies

vs. radius

Plasma density vs. radius

slide15

DSXEnergetic Particle Environment

> 2 MeV electrons vs. radius

> 36 MeV protons vs. radius

slide16

DSXLightning Climatology

Satellite-Derived (LIS/OTD) MonthlyGlobal 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
slide17
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

slide18

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
slide19

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
slide20

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 ?
slide21

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
slide22

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
slide23

DSXSchedule of Milestones

Bus Deliveries

CEASE

LEESA

VMAG

SET-1

LCI

PM

Hardware Delivery Window

AUG‘08

JUL’09

Avionics Module

PL Deliveries

Critical Path

Rad/Photom

Flt Battery

HEPS

ECS

SA

AM

Payload Module

Separation System 06/02/10

ESPA

Y-Antenna

Z-Antenna

LIPS

WIPER

HIPS

DSX AI&T (AFRL)

TacSat-3

Last update 1/22/09

slide24

DSXThe Team

Space Environmental

Effects

PROPULSION

DIRECTORATE

Program Office

Systems Engineering

Integration and Test

Launch Segment

Spacecraft Bus

VLF Wave-Particle Interaction Experiment

Space Weather

Experiments

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