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DSX Briefing RBSP Science Gateway

VIEWS: 4 PAGES: 24

									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

• 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          Particle lifetime along field lines
                                                             along field lines               (approximate 1D solution)



                                                                                              
                                                                                              
                                                                                           f X ,t 1                             
                                                                                                                                   
                                                                                                                                f X ,t
                            Natural VLF
                                                                                             t
                                                                                                  =
                                                                                                       
                                                                                                        ij
                                                                                                                   D X i X j
                                                                                                              Xi 
                                                                                                                                Xj      
                                                                                                                                          
         Wave power in the                           Diffusion coefficients
          magnetosphere                                 along field lines
                                                                                          Full 3D global, time dependent
                                                                                               particle distributions
                                                              Distribution of Resonant             Xi = (L, E,  )
                                                                    Wave Vectors


                                                                                           Quantitative understanding
          Wave-particle resonance condition
                                                                                           of VLF wave power
                                                                                           distribution & resultant
                                                                                           wave-particle interactions is
                                                                                           crucial for radiation belt
                                                          Complex dependence on energy,
                                                                                           specification & forecasting
      Diffusion coefficients = sum over resonances          frequency, and pitch angle
                                                                   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                                         0>
                                                                                              +                                     -
                                                                                                                                                      >0
                                                                                                                                    -
  • Far-field radiation a result of complex current distribution                          +                   Iantenna
                                                                                                                     -
                                                                                                                            -                     -
                                                                                                  +       +
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)                                  1-D equivalent circuit
  •   Linear-response cold plasma theory in far-field (Stanford, UM/Lowell, AFRL, etc.)              (UMass/Lowell)
Validation with LAPD in laboratory plasmas (UCLA)

                             Electrostatic potential (Volts)     +300

                                                                 +10
                                                                 -10

                                                    VLF loop antenna



                                                                 -10000

                  3-D electrostatic antenna simulation
                          (NASCAP-2k, SAIC)                               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)
                                                                                                                                         (>2.5 MeV e ; >135 MeV p)




                                                                                         Dose Rate (Rads/s)
                                                                                                              Behind 0.23” Al
                                                            J. Fennell,
                                                            SEEWG 2003




                                                                                                                                                  L (RE)
                               HEO dose measurements show that current radiation      For MEO orbit (L=2.2), #years to reach 100 kRad:
                               models (AE8 & AP8) over estimate the dose for           • Quiet conditions (NASA AP8, AE8) : 88 yrs
                               thinner shielding                                       • Active conditions (CRRES active) : 1.1 yrs
                                                                                      AE8 & AP8 under estimate the dose for 0.23’’ shielding
                            Model differences depend on energy:
Omni. Flux (#/(cm2 s Mev)




                                      L (RE)                              L (RE)                                                L (RE)                               L (RE)
                                  DSX
                         Where is the 20 dB?

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




                                       ≠



Ground transmitter VLF needed in the inner magnetosphere… but where is it?
                             Radiation Belt Remediation
                                                     DSX Satellite                                                For Official Use Only




                                                           AC Magnetometer             Wave-Particle Interactions (WPIx)
                                                            – Tri-axial search coils      – VLF transmitter & receivers
                                                                                          – Loss cone imager
                                                                                       Space Weather (SWx)
                                          8m                                              – 5 particle & plasma detectors
                                               Z-Axis Booms                            Space Environmental Effects (SFx)
                                               • VLF E-field Rx                           – NASA Space Environment Testbed
                                                                                          – AFRL effects experiment

                                                                                                  ESPA Ring
                                                                                                    • Interfaces between EELV
Loss Cone Imager                                                                                      & satellite
 - High Sensitivity Telescope
 - Fixed Sensor Head
                                          VLF Transmitter & Receivers
                                           - Broadband receiver
                    Y-Axis Booms           - 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)
 – Two dipole antennas (2 E components)                                   Transmitter control & tuning units

 – Frequency range: 100 – 50 kHz




                                                                              trol
                                                                        - Con
                                                                         amp




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




                                                                  - Pre
                                                                   - Ex
• Transmitter (UMass Lowell, SWRI, Lockheed-Martin):                                               NASA GSFC   14 May 2007



 – 3 – 50 kHz at up to 500 W (900 W at end of life)                              Broadband receiver &
                                                                                  tri-axial search coils
 – 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
                                                                                             Loss Cone Imager
 – Fixed Sensor Heads (FSH): 130 deg x 10 deg of pitch angle distribution                       HST & FSH
   for 50 – 700 keV electrons every 167 msec
• 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
                                                                                          Vector magnetometer
                        controlled manner                                                                           10
                                                    DSX
                                   Space Weather Payload
Plasmasphere       Ring current & aurora                  Radiation belts

      Protons                                                       HIPS
                                    LIPS                           HEPS
                                                                                           HEPS
               LEESA
                                                                   CEASE
                                           CEASE
     Electrons                                     HIPS
                                 LCI-FSH
                                    LIPS                                           HIPS
               LEESA                                 HEPS

 0.0001    0.001       0.01        0.1       1            10         100    1000
                                   Energy (MeV)                                                   CEASE
                          Energy (MeV)
 CEASE - Compact Environment Anomaly Sensor (Amptek, AFRL)
 LEESA - Low Energy Electrostatic Analyzer (AFRL)
 LIPS - Low Energy Imaging Particle Spectrometer (PSI)                              LIPS
 HIPS - High Energy Imaging Particle Spectrometer (PSI)
 HEPS - High Energy Particle Sensor (Amptek, ATC)

    Comprehensive SWx sensor suite will map full range of MEO                                 LEESA
                    space particle hazards
                                                                                                          11
                                                     DSX
                           Space Weather Effects Payload

CREDANCE                                                                  Photometers



                                 SET Carrier (NASA-GSFC)

NASA Space Environment Testbed (SET)                                                          1”
• CREDANCE (QinetiQ)
    – Cosmic Radiation Environment Dosimetry and Charging
      Experiment
• DIME (Clemson Univ)
    – Dosimetry Intercomparison and Miniaturization
• ELDRS (Arizona State)                                                     Radiometers
    – Development of space-based test platform for the
                                                                AFRL/PRS “COTS” sensors
      characterization of proton effects and Enhanced Low
      Dose Rate Sensitivity (ELDRS) in bipolar junction         Objective: directly measure changes in
      transistors                                                 • Optical transmission,
• COTS-2 (CNES and NASA)                                          • Thermal absorption
                                                                  • Thermal emission
    – Validation of single event effects mitigation via fault
      tolerant methodology                                      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,                 Equatorial pitch-angles vs. L*
120 deg inclination
                            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


•   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


• 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
                                  AUG‘08 Hardware Delivery Window                        JUL’09                                      Bus Deliveries
   Avionics Module   Rad/Photom                                                                                                      PL Deliveries




                                                                         SA
                                                        Flt Battery
                                                                                                                                     Critical Path

                                          HEPS
                                   ECS




                                                                         AM




                                                                                                        Separation System 06/02/10
  Payload Module




                                                                                 Y-Antenna
                                   Z-Antenna




                                                 ESPA




                                                                      CEASE




                                                                                 WIPER
                                                                      LEESA
                                   VMAG
                     SET-1




                                                                      LIPS




                                                                                 HIPS



                                                                                                  LCI
                                   PM




DSX AI&T (AFRL)
                                                                              TACSAT-3




                                                                                                                                     Last update 1/22/09
                                        DSX
                                    The Team
      Program Office                                  Launch Segment
   Systems Engineering
   Integration and Test


                                                       Spacecraft Bus




VLF Wave-Particle Interaction
       Experiment



                                Space Environmental    Space Weather
                                      Effects           Experiments




                                PROPULSION
                                DIRECTORATE

								
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