TYPICAL DRAG PARAMETERS B(kg/m, CD LANDSAT 25-12334-4 ERS-1 12-1354 hubble 29-19233-49000g Echo 1 0.515 Typically Cp.2-4 for spacecraft. (see SMAD Table8.) △ v over one year(β=100kg/m2) h(km)△vear(m/s 100 200 2-5x 10 solar(min-max 300 40-600 3200
TYPICAL DRAG PARAMETERS 16 E (kg/m 2) C D LANDSAT 25 - 123 3.4 - 4 ERS - 1 12 - 135 4 Hubble 29 - 192 3.3 - 4 90,000Kg Echo 1 0.515 2 Typically C D ~ 2.2 - 4 for spacecraft. (see SMAD Table 8.3) 'V over one year ( E = 100 kg/m 2 ) h (km) 'V /year (m/s) 100 10 7 200 2 - 5 u 10 3 solar (min - max) 300 40 - 600 400 3 - 200
SATELLITE LIFETIMES Large variation depending on initial altitude and solar min/max condition(see SMAD Fig 8-4) At leo, design must compensate for effects of rag
17 SATELLITE LIFETIMES Large variation depending on initial altitude and solar min/max condition (see SMAD Fig. 8 - 4) At LEO, design must compensate for effects of drag
MAGNETIC FIELD EFFECTS Deflects charged particles/solar wind South Atlantic anomaly Creates the structure of the ionosphere/plasmasphere Magnetosphere Van allen radiation belts Direct effects on Spacecraft systems Avionics-induced potential effects Power-induced potential effects GN&C- magnetic torquer performance, sizing Structures -induced currents tt&c- location of saa
MAGNETIC FIELD EFFECTS 18 • Deflects charged particles/solar wind. – South Atlantic Anomaly • Creates the structure of the ionosphere/plasmasphere – Magnetosphere – Van Allen radiation belts • Direct effects on Spacecraft systems – Avionics - induced potential effects – Power - induced potential effects – GN&C - magnetic torquer performance, sizing – Structures - induced currents – TT&C - location of SAA
GEOMAGNETIC FIELD Earth's Magnetic field comes from three sources internal field (99% currents inside the earth residual magnetism of elements contained in crust External field 1% Currents in the magnetosphere B: internal field varies slowly on the order of 100 years (0.05%/year) Poles of magnetic field lie in Siberia and South australia
GEOMAGNETIC FIELD 19 • Earth’s Magnetic field comes from three sources – internal field (99%) • currents inside the Earth • residual magnetism of elements contained in crust – External field 1% • Currents in the magnetosphere • Bi internal field varies slowly on the order of 100 years (0.05%/year.) • Poles of magnetic field lie in Siberia and South Australia
GEOMAGNETIC FIELD 60 30 Unt(Total mEnen): nanoTech Unts (Annual Change): nano Toclas Contu Interval: 2000 nno Techs Conour InteNal: 10 nano Teclast Map Ppjocton: Blode tp Photon: Mollweide
20 GEOMAGNETIC FIELD