Landsat 1
Landsat 1, originally named "Earth Resources Technology Satellite 1", was the first satellite of the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...

' Landsat program
Landsat program
The Landsat program is the longest running enterprise for acquisition of satellite imagery of Earth. On July 26, 1972 the Earth Resources Technology Satellite was launched. This was eventually renamed to Landsat. The most recent, Landsat 7, was launched on April 15, 1999. The instruments on the...

. It was a modified version of the Nimbus 4 meteorological
Meteorology is the interdisciplinary scientific study of the atmosphere. Studies in the field stretch back millennia, though significant progress in meteorology did not occur until the 18th century. The 19th century saw breakthroughs occur after observing networks developed across several countries...

In the context of spaceflight, a satellite is an object which has been placed into orbit by human endeavour. Such objects are sometimes called artificial satellites to distinguish them from natural satellites such as the Moon....

 and was launched on July 23, 1972 by a Delta 900
Delta 0100
The Delta 0100 series, also Delta 100, 0300 or 300 series, was an American expendable launch system which conducted orbital launches between 1968 and 1972. It was a member of the Delta family of rockets, and the first to be designated using a four digit numerical code...

 rocket from Vandenberg Air Force Base
Vandenberg Air Force Base
Vandenberg Air Force Base is a United States Air Force Base, located approximately northwest of Lompoc, California. It is under the jurisdiction of the 30th Space Wing, Air Force Space Command ....

 in California
California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...

. The near-polar orbit
Polar orbit
A polar orbit is an orbit in which a satellite passes above or nearly above both poles of the body being orbited on each revolution. It therefore has an inclination of 90 degrees to the equator...

ing spacecraft served as a stabilized, Earth-oriented platform for obtaining information on agricultural and forestry resources, geology and mineral resources, hydrology and water resources, geography, cartography, environmental pollution, oceanography and marine resources, and meteorological phenomena.

To accomplish these objectives, the spacecraft was equipped with:
  • a three-camera return-beam vidicon (RBV) to obtain visible light and near infrared photographic images of Earth;
  • a four-channel multispectral scanner (MSS) to obtain radiometric images of Earth;
  • a data collection system (DCS) to collect information from remote, individually equipped ground stations and to relay the data to central acquisition stations.

The satellite also carried two wide-band video tape recorders (WBVTR) capable of storing up to 30 minutes of scanner or camera data, giving the spacecraft's sensors a near-global coverage capability.

An advanced attitude control system consisting of horizon scanners, sun sensors, and a command antenna combined with a freon gas propulsion system permitted the spacecraft's orientation to be maintained within plus or minus 0.7 degrees in all three axes. Spacecraft communications included a command subsystem operating at 154.2 and 2106.4 MHz and a PCM narrow-band telemetry subsystem, operating at 2287.5 and 137.86 MHz, for spacecraft housekeeping, attitude, and sensor performance data. Video data from the three-camera RBV system was transmitted in both real-time and tape recorder modes at 2265.5 MHz, while information from the MSS was constrained to a 20 MHz radio-frequency bandwidth at 2229.5 MHz.

In 1976, Landsat 1 discovered a tiny uninhabited island 20 kilometers off the eastern coast of Canada. This island was thereafter designated Landsat Island
Landsat Island
Landsat Island is a small, uninhabited island located 20 km off the northeast coast of Labrador . It was discovered in 1973 during the analysis of imagery from the Landsat 1 satellite...

 after the satellite. As of 2006, it is the only island to be discovered via satellite imagery.

The spacecraft was turned off on January 6, 1978, when cumulative precession
Precession is a change in the orientation of the rotation axis of a rotating body. It can be defined as a change in direction of the rotation axis in which the second Euler angle is constant...

 of the orbital plane
Orbital plane
Orbital plane may refer to:*Orbital plane *In anatomy, it refers to a specific area of the maxilla...

caused the spacecraft to become overheated due to near-constant exposure to sunlight.
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