ESSA-6
Names | TOS-D |
---|---|
Mission type | Weather |
Operator | NASA |
COSPAR ID | 1967-114A |
SATCAT no. | S03035 |
Spacecraft properties | |
Launch mass | 145 kg (320 lb) |
Start of mission | |
Launch date | November 10, 1967, 18:00 UTC GMT |
Rocket | Delta |
Launch site | Vandenberg Air Force Base |
Orbital parameters | |
Reference system | Geocentric orbit |
Regime | Low Earth orbit |
Eccentricity | 0.00498 |
Perigee altitude | 1,410 km (880 mi) |
Apogee altitude | 1,488 km (925 mi) |
Inclination | 102.12° |
Period | 114.82 minutes |
ESSA program |
ESSA 6 (or TOS-D) was a spin-stabilized operational meteorological satellite.[1] Its name was derived from that of its oversight agency, the Environmental Science Services Administration (ESSA).
Details
[edit]ESSA 6 had a mass of 299 kilograms (659 lb) 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 (Automatic Picture Transmission) 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 108° F/1.8 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.[2]
The base featured crossed-dipole antennas for command reception, while a monopole antenna provided telemetry (136.500 MHz) and tracking (136.770 MHz) from the top.
Spin rate was regulated to 10.9 rpm using a Magnetic Attitude Spin Coil (MASC), which interacted with Earth's magnetic field to maintain a stable spin axis normal to the orbital plane, within ±1 degree.[1]
Mission
[edit]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 1,410 kilometers (880 mi) and its apogee was 1,488 kilometers (925 mi).[3]
The satellite performed normally after launch.
The APT camera system was successful, operating nearly continuously until November 4, 1969 when the spacecraft was deactivated.[2]
References
[edit]- ^ a b "ESSA 6". NSSDCA.
- ^ a b "ESSA 6 Automatic Picture Transmission (APT) System". NSSDCA.
- ^ "Launch/Orbital information for ESSA 6". NSSDCA.
This article incorporates public domain material from ESSA 6. National Aeronautics and Space Administration. Retrieved June 4, 2018.