APPENDIX B 

 Glossary and List of AblDreviations 



Glossary 



APOGEE: That point in an ortit farthest from the center of the 



earth, (see perigee) 

 ASCEHDING NODE: The point at which an orhlting "body crosses the 



Equator northhoundj identified hy time and longitude, (see 



descending node) 

 ATMOSPHERIC WINDOW: An area which allows good transmission of 



infrared radiation through the atmosphere with minimum 



ahsorption "by water vapor or C02» 

 BLIND ORBIT: An orbit during which a satellite cannot he 



Interrogated "because it does not come within range of any ground 



station, or when no grouad station is available due to schedule 



conflicts . 

 DEGRADATION: The lessening of picture image quality because of 



noise or any optical, electronic, or mechanical distortions in 



the image -forming system* 

 DESCENDING NODE: The point at which an orbiting body crosses the 



Equator southbound; identified by time and longitude, (see 



ascending node) 

 GEO-SYNCHRONOUS ORBIT: A prograde orbit of 2U-hour period; the 



satellite appears to hover motionless over a fixed location, 



normally on the Equator o Also called earth- synchronous, (see 



sun-synchronous orbit) 



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