TOS
TIROS Operational System

TOS spacecraft marked the first operational system of US polar-orbiting meteorological satellites. TOS was a follow-on to the TIROS (Television Infrared Observation Satellite) series, and was itself followed by the ITOS (Improved TIROS) series, and later the NOAA series. TIROS spacecraft were developed by GSFC and managed by ESSA (Environmental Science Services Administration). The objective was to establish a global weather satellite system. The TOS spacecraft are also referred to as ESSA spacecraft.

Spacecraft
Body mounted solar cells.

Payload
TOS/ESSA spacecraft carried television cameras, APT (Automatic Picture Transmission) systems, and AVCS (Advanced Vidicon Camera System) instruments.

Country of Origin	United States
Customer/User	ESSA, NASA, GSFC, NOAA
Manufacturer(s)	RCA
Size	Cylinder: 42 inch diameter, 22 inch height
Orbit	approx. 1400 km, polar, circular

Launch Facts

Name	Int'l Desig.	Date	Site	Vehicle	Orbit	Mass(kg)
Notes
ESSA 1	1966-008A	2/3/66	ESMC	Delta C	LEO	138
Environmental Survey Satellite
ESSA 2	1966-016A	2/28/66	ESMC	Delta E	LEO	132
Environmental Survey Satellite; carried APT cameras
ESSA 3	1966-087A	10/2/66	WSMC	Delta E	LEO	145
Environmental Survey Satellite 3; replace ESSA 1
ESSA 4	1967-006A	1/26/67	WSMC	Delta E	LEO	132
Replaced ESSA 2
ESSA 5	1967-036A	4/20/67	WSMC	Delta E	LEO	145
Replaced ESSA 3
ESSA 6	1967-114A	11/10/67	WSMC	Delta E	LEO	132
Returned cloud cover images
ESSA 7	1968-069A	8/16/68	WSMC	Delta N	LEO	145
ESSA 8	1968-114A	12/15/68	WSMC	Delta N	LEO	132
ESSA 9	1969-016A	2/26/69	ESMC	Delta N	LEO	145