PDS_VERSION_ID                     = PDS3                                     
RECORD_TYPE                        = STREAM                                   
                                                                              
OBJECT                             = INSTRUMENT_HOST                          
  INSTRUMENT_HOST_ID               = "IRAS"                                   
                                                                              
  OBJECT                           = INSTRUMENT_HOST_INFORMATION              
    LAUNCH_DATE                    = 1983-01-26                               
    INSTRUMENT_HOST_NAME           = "INFRARED ASTRONOMICAL SATELLIT"         
    INSTRUMENT_HOST_TYPE           = "SPACECRAFT"                             
    INSTRUMENT_HOST_DESC           = "                                        
                                                                              
  The IRAS satellite consisted of two main parts, the spacecraft and          
  the telescope system. The overall dimensions of the satellite with          
  deployed solar panels were: height 3.60 m, width 3.24 m, depth 2.05 m.      
  atellite mass at launch was 809 kg. The telescope system comprised          
  comprised the upper part of the satellite and was composed of a two mirror, 
  Ritchey-Chretien telescope mounted within a toroidal superfluid helium tank,
  which in turn was mounted within the evacuated main shell. The optical      
  system was protected from contamination before launch and during the        
  first week of the mission by an aperture cover cooled with supercritical    
  helium.  After the cover was ejected, the sunshade limited heat flow to     
  the aperture by blocking direct solar radiation and reflecting away         
  terrestrial infrared radiation. The telescope was cooled by contact with    
  the superfluid helium tank to temperatures ranging from 2 to 5 K.           
  The surfaces of the sunshade which could be viewed by the telescope         
  aperture were cooled by a three-stage radiator to about 95 K.               
                                                                              
  The satellite attitude was controlled by three orthogonal reaction wheels;  
  excess momentum was dumped via magnetic coils to the Earth's magnetic field 
  as necessary. The attitude, and changes in attitude, were sensed by a       
  combination of a horizon sensor, a sun-sensor and three orthogonal gyros.   
  The z-axis gyro was used in all modes of control and was duplicated to      
  provide a redundant backup."                                                
                                                                              
  END_OBJECT                       = INSTRUMENT_HOST_INFORMATION              
                                                                              
  OBJECT                           = INSTRUMENT_HOST_REFERENCE_INFO           
    REFERENCE_KEY_ID               = "BEICHMANETAL1988"                       
   END_OBJECT                      = INSTRUMENT_HOST_REFERENCE_INFO           
                                                                              
  OBJECT                           = INSTRUMENT_HOST_REFERENCE_INFO           
    REFERENCE_KEY_ID               = "NEUGEBAUERETAL1984"                     
   END_OBJECT                      = INSTRUMENT_HOST_REFERENCE_INFO           
                                                                              
END_OBJECT                         = INSTRUMENT_HOST                          
                                                                              
END