Space Climatology Models in the Context of Space Weather

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Space Climatology Models in the Context of Space
Weather Workshop on New Standard Radiation Belt
and Space Plasma Models for Spacecraft
Engineering 5-8 Oct 04
G. P. Ginet Air Force Research Laboratory
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Why New Standard Radiation Belt and Plasma Models?

• New technologies missions are increasingly
  susceptible to space environment hazards
• Better models are needed for smart system
  acquisition
• Broader energy range, both upper (gt 100 MeV) and
  lower (lt 1 MeV)
• More detailed spectral pitch angle resolution
• Probability of threshold occurrence duration
  for 10 year missions
• Better models will reduce acquisition costs,
  improve capabilities and extend mission lifetimes
• Willing to wager that AP-8 and AE-8 are one of
  the top two most applied space weather model sets
  outside of the space physics science community
• Improved models will have a large impact on
  society for LWS
• Other model ionosphere correction algorithm in
  single frequency GPS receivers

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Radiation Levels of Concern
Soft (lt40)
Tolerant (40-120)
Hard (gt120)
Soft (lt40)
Tolerant (40-80)
Hard (gt80)
SEU (LET) MeV/mg/cm2
SEL (LET) MeV/mg/cm2
0
40
80
120
160
20
40
60
80
100
Tolerant w/EDAC (10-6-10-8)
Tolerant w/ shielding (20-100)
Tolerant (100-500)
Tolerant (10-8-10-10)
Soft (gt10-6)
Hard (lt10-10)
Soft (lt20)
Hard (gt500)
SEU (err/b-d)
Total Dose (rad)
10-4
10-6
10-8
10-10
10-12
103
104
105
106
107
Hard (109-1010)
Tolerant (107-109)
Operate Through (gt1010)
Soft (lt1012)
Hard (gt1014)
Tolerant (1012-1014)
Soft (lt20)
Dose Rate (rad/sec)
Neutron (n/cm2)
1011
1012
1013
1014
1015
106
107
109
1010
1011
Note surface deep charging not included
From S. Tyson, AFRL/VSS
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Radiation EnvironmentsDSX MEO Orbit Study
Orbit 1
Orbit 2
Orbit 3
Orbit 4
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Radiation EnvironmentsRadiation Dose 1 year
105
104
rads(Si)/yr
103
Quiet
102
101
106
105
rads(Si)/yr
Active
104
103
102
From CRRESRAD model
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Spacecraft DesignThe Problem
Example Medium-Earth Orbit (MEO)
Example Highly Elliptic Orbit (HEO)
Model Dose rates behind 0.23 Al (gt2.5 MeV e
gt135 MeV p)
DOSE (Rads/s)
J. Fennell, SEEWG 2003
L (RE)

• For MEO orbit (L2.2), 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
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Space Environment ModelsDynamic Electron
Environment
Electrons gt 1.2 MeV (protons gt 78 MeV)
Electrons gt 0.55 MeV (protons gt 40 MeV)
Electrons gt 3.5 MeV (protons gt 86 MeV)
L-shell

• Halloween Storm analysis
• Empty slot region fills up with energetic
  electrons for gt 20 days
• Anomalously long lifetime observed for gt1.2 MeV
  electron channel

Existing models inadequate for satellite design
(climatology) or situational awareness
(nowcast-forecast)
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Space Environment ModelsSevere Electron
Environments
Electrons gt 1.2 MeV (protons gt 78 MeV)
Electrons gt 3.5 MeV (protons gt 86 MeV)
Electrons gt 0.55 MeV (protons gt 40 MeV)
L-shell
Electrons gt 7 MeV (protons 21-36 MeV)

• July 2004 Storm analysis
• Lower inner belt region fills up with energetic
  electrons for gt 35 days
• Extremely hard electron spectrum
• By far the worst seen in 4 years of CEASE/TSX5
• Set record for GOES gt 2 MeV daily ave

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New Standard ModelsThe User Mandate

• Space Technology Alliance (STA) - DoD, NASA,
  DoE, NOAA
• STA subgroup Space Environment Effects Working
  Group (SEEWG)

• SEEWG Workshop 2002 Space Environment Effects
  on Large Imaging Systems
• Recommendations
• Create technical committee to develop updated
  radiation environment models
• International group needed
• U.S. national group could be under SEEWG Rad.
  Envir. subcommittee
• Support improved data and modeling for energetic
  protons and electrons for 1ltLlt3.5
• Support collection of data for low energy plasmas
  between LEO and GEO (1ltLlt6)
• Fly radiation measurement instruments on as many
  operational satellites as possible
• Build dynamic outer zone (MEO orbit regime)
  electron model
• Internal surface charging specifications are
  needed
• SEEWG Workshop 2003 on Space Environment Effects
  on Transformational Communications Architectures
  provided similar recommendations
• STA charged SEEWG to go forth and do it

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Technical Challenges

• Clean up and cross-calibrate a diverse data set
• Remove contamination by high energies, other
  species, secondaries, etc.
• Quantify often sparse energy and pitch angle
  resolution
• Assimilate diverse data sets into a coherent
  global picture
• Back-out best guess local energy pitch angle
  spectra
• Map set of local measurements into global
  distribution
• Determine most useful output for design community
• Map orbit space into space physics domains
• Estimate probability of occurrence and duration
  for multiple time scales
• Determine activity fidelity and drivers, e.g.
  SSN, Kp, Dst, F10.7
• Design an easily extensible model
• Validate with ground truth data not in the model

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Political Challenges

• ALL concerned parties need to accept new standard
• Satellite builders IEEE, AIAA, etc.
• Satellite users NASA, ESA, DoD, Direct TV,
  Virgin Galactic, etc.
• Approver organizations ISO, ANSI,COSPAR, STA,
  etc.
• Model developers AGU, NSF, National Labs, NASA,
  ESA
• Acceptance can be pursued in parallel to model
  development
• But will require proof that new standard is
  better
• Need international data and model exchange
  agreements
• Funding has to be pursued
• Well defined, high-priority requirements
• Coherent, executable plan with deliverables
• Who pays?
• Satellite users and builders
• Research organizations

Builders, users, approvers and developers all
need to be on-board
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Climatology Role Space Weather

• High priority SWx product
• Building new standard models requires science
• Detector characterization
• Optimal spectral and pitch-angle
  characterization
• Assimilation into global picture
• Climatology provides initial conditions and
  defaults for nowcast and forecast models

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Where do we go from Here?

• Continue New Standard Radiation Belt group
  convened this week
• Coordinate developers and resources currently
  engaged
• Address time-critical program and technical
  issues
• Develop proposal for development of new standard
  models
• Identify costs, schedule, milestones, products
• First GEO, LEO then MEO
• Draft end-to-end model structure with example
• Decide on ultimate COSPAR oversight role and
  delineate responsibilities
• Engage NASA and DoD international affairs people
  to develop data and model exchange agreements
• Develop user, builder, approver and developer
  briefings and hit the road

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Conclusions
HEO
GEO
MEO
LEO
10-100 MeV protons
1-10 MeV electrons
Thanks to Janet, Don, Bern and Eamon for putting
together a great workshop!