A Note About Satellite Names 



The names of satellites and their operational systems are a 

 confusing conglomerate of acronyms. It is hoped that the following 

 discussion will help arrange them in some logical order. 



The Television Infrared Observational Satellites (TIROS) were 

 weather research satellites operated by the National Aeronautics 

 and Space Administration (NASA). There have been ten of these research 

 satellites launched between April I96O and July 1965- 



The successful development of TIROS led to the TIROS Operational 

 System or TOS . As the name implies, the satellites used in the TOS 

 system are operational rather than research satellites. These operational 

 satellites are managed by ESSA's National Environmental Satellite 

 Center (NESC) after being initially launched and checked out by NASA's 

 Goddard Space Flight Center (GSFC). This system requires two TOS 

 satellites to be in orbit at all times. One satellite carries APT 

 for direct readout to ground stations and the other is equipped with 

 AVCS for readout to command stations at Chlncoteague , Virginia and 

 Gilmore Creek, Fairbanks, Alaska. 



The first satellites of the TOS system were the Environmental Survey 

 Satellites (ESSA). There have been eight of these satellites to date, 

 the odd numbered ones equipped with AVCS, the even numbered ones with APT. 



With the launching of TIROS M in midyear I969 , the second generation 

 of the TOS system will be inaugurated. Once in orbit, TIROS M will be 

 redesignated as an Improved TIROS Operational Satellite (ITOS) and will 

 be capable of performing the work of two ESSA satellites in addition to 

 having infrared data collecting capabilities. 



48 



