ESSA-6

ESSA 6 was a spin-stabilized operational meteorological satellite. Its name was derived from that of its oversight agency, the Environmental Science Services Administration.

Details

ESSA 6 had a mass of at the time of launch.
The satellite's electrical power was supplied by about 10,000 1x2 cm solar cells on the cover and 21 nickel-cadmium batteries.
Two redundant wide-angle APT cameras, mounted on opposite sides and perpendicular to the spin axis, captured images. This subsystem was a camera-transmitter setup, designed to transmit real-time daylight images of cloud cover to ground stations. It included two 2.54-cm vidicon cameras with lenses, mounted 180° apart. Each orbit, the cameras captured four or eight images, with picture taking lasting 8 seconds and transmission 200 seconds. The 800-line images were transmitted at 137.5 MHz to local APT stations, with reticle marks on the images to assist with geographical alignment. Each picture covered a 3100 x 3100 km area with 4 km resolution at nadir, with a 30% overlap to ensure complete coverage.
The base featured crossed-dipole antennas for command reception, while a monopole antenna provided telemetry and tracking from the top.
Spin rate was regulated to 10.9 rpm using a Magnetic Attitude Spin Coil, which interacted with Earth's magnetic field to maintain a stable spin axis normal to the orbital plane, within ±1 degree.

Mission

ESSA 6 was launched on November 10, 1967, at 18:00 UTC, atop a Delta rocket from Vandenberg Air Force Base, California, USA.
ESSA 6 had an inclination of 102.12°, and orbited the Earth once every 114.8 minutes. Its perigee was and its apogee was.
The satellite performed normally after launch.
The APT camera system was successful, operating nearly continuously until November 4, 1969 when the spacecraft was deactivated.