THERMOSPHERE EMPERICAL MODEL UPDATE

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THERMOSPHERE EMPERICAL MODEL UPDATE 4TH
(VIRTUAL) THERMOSPHERIC/IONOSPHERIC GEOSPHERIC
RESEARCH (TIGER) SYMPOSIUM INTERNET JUNE 10-14,
2002 Jerry K. Owens NASA Marshall Space Flight
Center And William W. Vaughan University of
Alabama in Huntsville
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NASA MARSHALL ENGINEERING THERMOSPHERE MODEL
BACKGROUND

• Model Scope
• Thermosphere About 90 to 500 Kilometers
  Altitude
• Exosphere Above About 500 Kilometers
  Altitude
• Important Applications
• Torques and Drag on Orbiting Spacecraft and
  Orbital Debris
• Modulation of Trapped Radiation Flux at
  Orbital Altitudes
• Model Basis
• Extensive Work of Luigi Jacchia and Colleagues
  at Smithsonian Astrophysical Observatory During
  1960s and 1970s
• Work on Spacecraft Orbital Altitudes Neutral
  Density since 1960s
• Developed Originally for Satellite Orbital
  Lifetime Predictions, Mission Analysis for
  Re-Boost Requirements, etc.

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NASA MARSHALL ENGINEERING THERMOSPHERE MODEL
DEVELOPMENT

• Jacchia 1964 Model
• Jacchia 1970 Model
• Jacchia 1971 Model
• MSFC/Jacchia 1970 Orbital Atmosphere Model
• NASA MET Model 1988 Version
• NASA MET Model 1999 Version
• NASA MET Model Version 2.0

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NASA MARSHALL ENGINEERING THERMOSPHERE MODEL
DESCRIPTION

• Density Distribution
• Barometric and Diffusion Equations
• Composition
• Gravity Field
• Temperature Profile

• Variations
• Solar Activity
• Diurnal
• Geomagnetic Activity
• Semiannual
• Seasonal - Latitudinal
• Solar Position

• Thermodynamic Quantities
• Pressure
• Pressure Scale Height
• Specific Heat Capacities

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NASA MARSHALL ENGINEERING THERMOSPHERE MODEL
PROGRAM USAGE

• Solar and Geomagnetic Activity Input Parameters
• After-the-Fact Calculations
• Real Time Calculations
• Future Applications
• Model Output Parameters
• Temperature
• Number Densities
• Mass Density (Total Neutral Density)
• Total Pressure

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NASA MARSHALL ENGINEERING THERMOSPHERE MODEL
CONCLUDING REMARKS

• State-of-the-Art Accuracy for Models Total
  Neutral Density Calculations
• Future Total Neutral Density Estimates Accuracy
  Using Model
• Significant Dependence on Accuracy of Model
  Inputs for Estimates of Future Solar Radio
  Flux and Geomagnetic Activity
• MODEL SOURCE
• Jerry K. Owens, NASA Marshall Space Flight Center
  (jerry.owens_at_msfc.nasa.gov)