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SPACE WEATHER EFFECTS ON SATELLITE DRAG
6 January 2006
Cheryl Huang, Frank A. Marcos and William Burke
Space Vehicles Directorate
Air Force Research Laboratory
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Marcos et al., 1997
AFRL Atmospheric Calibration Technique Results
Operational data
Drag model corrected
Historic Errors in Empirical Models
Model errors reduced from 15% to 5%
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• AF Space Battlelab Initiative
• Objective: Near real time corrections to J70 model, enhanced spatial resolution
- Drag from ~75 LEO calibration satellites
- Range of altitudes (200-800 km) and inclinations
- Enhanced Tracking
• Error reduced to 8%
• Operational: Sept 2004
High Accuracy Satellite Drag Model (HASDM)
• AFRL Support:
- Technical consultation
- Extend operational model below 90 km
- Evaluate candidate solar proxies
- Evaluate spatial resolution
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Sapphire Dragon (HASDM-2)
• AF Space Battlelab Initiative to upgrade current HASDM
• Objective: 3-day forecast with improved resolution and accuracy (TBD); 180 - 800 km
– Track 240 satellites
– Improve model parameterizations for semiannual, latitude, local time, solar and geomagnetic variations
• Model complete April 2006
– AFRL will provide model operational algorithms for local time vs latitude, altitude and solar flux
• Validation complete August 2006
– AFRL will present results at Aug 06 Astrodynamics Conference
• Operational in 2008
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Predicted Position
Actual Position
Superstorm Impacts: • Changed scale heights and wind patterns
• Degraded ability to track space objects
Electromagnetic Energy Flow
Undetected on the ground, hundreds to thousands of TeraJoules enter I/T
Interplanetary
MediumMagnetosphere Ionosphere/Thermosphere
Poynting vector measure of net
electromagnetic energy transfer
M-I-T Coupling and Satellite Drag
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M-I-T Coupling and Satellite Drag During Magnetic Storms
GRACE densities compared with model and PC predictions during November 7-10, 2004 magnetic storm
• MSIS and J 70 underestimate storm effects by 300%
• Fail to predict GRACE fine structure
• Predicted increases arrive 4 to 6 hours late
• ACE data from L1 give 4-hour forecast
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M-I-T Coupling and Satellite Drag
• During super storms, intense field-aligned currents impact upper ionosphere
• Storms introduce large quantities of stealth power (up to 3 TW) in the form of net Poynting flux into the upper ionosphere
• Modeled neutral densities underestimate observed increases
• Discrepancies significantly degrade predicted drag estimates
• PC estimates from ACE give several hour density predictions
Summary