The
earth
Earth is the third planet from the Sun and the only astronomical object known to harbor life. While large volumes of water can be found throughout the Solar System, only Earth sustains liquid surface water. About 71% of Earth's surfa ...
is constantly monitored by several
satellite
A satellite or artificial satellite is an object intentionally placed into orbit in outer space. Except for passive satellites, most satellites have an electricity generation system for equipment on board, such as solar panels or radioisotope ...
s operating in the ''earth exploration-satellite service'' (EESS)
or
space research service
Space research service (short: SRS | also: ''space research radiocommunication service'') is – according to ''Article 1.55'' of the International Telecommunication Union's (ITU) Radio Regulations (RR) – defined as ''«A radiocommunicat ...
(SRS). These artificial satellites have onboard
space radio station
Space radio station (short: space station) is a radio station located on an object travelling beyond the major portion of the Earth's atmosphere.ITU Radio Regulations, Section IV. Radio Stations and Systems – Article 1.64, definition: ''space ra ...
s from which they gather
data
In the pursuit of knowledge, data (; ) is a collection of discrete values that convey information, describing quantity, quality, fact, statistics, other basic units of meaning, or simply sequences of symbols that may be further interpreted ...
. The data is transmitted back to earth via
feeder link
A feeder link is – according to ''Article 1.115'' of the International Telecommunication Union´s (ITU) ITU Radio Regulations (RR)ITU Radio Regulations, Section IV. Radio Stations and Systems – Article 1.115, definition: ''feeder link'' – ...
s. This article lists a number of current active
Earth observation satellite
An Earth observation satellite or Earth remote sensing satellite is a satellite used or designed for Earth observation (EO) from orbit, including spy satellites and similar ones intended for non-military uses such as environmental monitoring, me ...
s and their
downlink
In a telecommunications network, a link is a communication channel that connects two or more devices for the purpose of data transmission. The link may be a dedicated physical link or a virtual circuit that uses one or more physical links or shar ...
transmission frequencies.
Frequency assignments
See also
*
List of Earth observation satellites
Earth observation satellites are earth-orbiting spacecraft with sensors used to collect imagery and measurements of the surface of the earth. These satellites are used to monitor short-term weather, long-term climate change, natural disasters ...
*
Radio waves
Radio waves are a type of electromagnetic radiation with the longest wavelengths in the electromagnetic spectrum, typically with frequencies of 300 gigahertz (GHz) and below. At 300 GHz, the corresponding wavelength is 1 mm (short ...
*
Frequency allocation
Frequency allocation (or spectrum allocation or spectrum management) is the allocation and regulation of the electromagnetic spectrum into radio frequency bands, normally done by governments in most countries. Because radio propagation does no ...
References
External links
Transmission at the S band
Earth observation satellites
Radio spectrum
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