1. 1 SPACE WEATHER EFFECTS ON SATELLITE DRAG 6 January 2006 Cheryl Huang, Frank A. Marcos and William Burke Space Vehicles Directorate Air Force Research Laboratory

2. 2 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%

3. 3 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

4. 4 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

5. 5 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 Medium Magnetosphere Ionosphere/Thermosphere Poynting vector measure of net electromagnetic energy transfer M-I-T Coupling and Satellite Drag

6. 6 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

7. 7 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