ESSA 3 [NASA]
The ESSA series was the second generation of US meterological satellites after the TIROS (Television & Infra-Red Observation Satellite) series. They were also called OT (Operational TIROS), TOS (TIROS Operational Satellite).
This desiign was a spin-stabilized operational meteorological spacecraft designed to take and record daytime cloudcover pictures on a global basis for subsequent playback to a ground acquisition station. The satellite had essentially the same configuration as that of the TIROS series, i.e., an 18-sided right prism, 107 cm across opposite corners and 56 cm high, with a reinforced baseplate carrying most of the subsystems and a cover assembly (hat). Electrical power was provided by approximately 10,000 1- by 2-cm solar cells that were mounted on the cover assembly and by 21 nickel-cadmium batteries.
Two redundant wide-angle cameras were mounted on opposite sides of the spacecraft and canted 75 deg from the spacecraft spin axis. A pair of crossed-dipole command and receiving antennas projected out and down from the baseplate. A monopole telemetry and tracking antenna extended up from the top of the cover assembly.
There were differences in the imaging system acorss the series:
The satellites were placed in a cartwheel orbital mode, with its spin axis maintained normal to the orbital plane. The satellite spin rate and attitude were determined primarily by a Magnetic Attitude Spin Coil (MASC). The MASC was a current-carrying coil mounted in the cover assembly. The magnetic field induced by the current interacted with the earth's magnetic field to provide the necessary torque to maintain a desired spin rate of 9.225 rpm. Five small solid-fuel thrusters mounted around the baseplate provided a secondard means of controlling the spacecraft spin rate.
|Type / Application:||Meteorology|
|Equipment:||2 × AVCS (#T9, 1, 3, 5, 7, 9); 2 × APT (#2, 4, 6, 8); FPR (#3, 5, 7, 9)|
|Power:||Solar cells, batteries|
|Mass:||138 kg (#T9, 1); 286 kg (#2, 4) 145 kg (#3, 5, 7, 9), 298 kg (#6, 8)|
|TIROS 9 (A 54)||1965-004A||22.01.1965||CC LC-17A||Delta-C|
|ESSA 1 (OT 3, TIROS 11)||1966-008A||03.02.1966||CC LC-17A||Delta-C|
|ESSA 2 (OT 2, TIROS 12)||1966-016A||28.02.1966||CC LC-17B||Delta-E|
|ESSA 3 (TOS 1, TIROS 13)||1966-087A||02.10.1966||Va SLC-2E||Delta-E|
|ESSA 4 (TOS 2, TIROS 14)||1967-006A||26.01.1967||Va SLC-2E||Delta-E|
|ESSA 5 (TOS 3, TIROS 15)||1967-036A||20.04.1967||Va SLC-2E||Delta-E|
|ESSA 6 (TOS 4, TIROS 16)||1967-114A||10.11.1967||Va SLC-2E||Delta-E1|
|ESSA 7 (TOS 5, TIROS 17)||1968-069A||16.08.1968||Va SLC-2E||Delta-N|
|ESSA 8 (TOS 6, TIROS 18)||1968-114A||15.12.1968||Va SLC-2E||Delta-N|
|ESSA 9 (TOS 7, TIROS 19)||1969-016A||26.02.1969||CC LC-17B||Delta-E1|
|ESSA 10 (TOS H)||-||cancelled|