Earth observation satellite

{{See also|Remote sensing#History}}

File:Lednickie Lake (Poland) seen by the American reconnaissance satellite Corona 98 (KH-4A 1023) (1965-08-23).png 98, 1965]]

Herman Potočnik explored the idea of using orbiting spacecraft for detailed peaceful and military observation of the ground in his 1928 book, The Problem of Space Travel. He described how the special conditions of space could be useful for scientific experiments. The book described geostationary satellites (first put forward by Konstantin Tsiolkovsky) and discussed communication between them and the ground using radio, but fell short of the idea of using satellites for mass broadcasting and as telecommunications relays.{{Cite web|url=http://www.sasmac.cn/portal/html/fc4f335929b0df0d0129b0e348f90003/_content/10_07/09/1278668367217.html|title=Introduction to satellite|website=www.sasmac.cn|date=2 September 2016|access-date=19 April 2017|archive-date=16 September 2016|archive-url=https://web.archive.org/web/20160916064537/http://www.sasmac.cn/portal/html/fc4f335929b0df0d0129b0e348f90003/_content/10_07/09/1278668367217.html|url-status=dead}}

The onset of the Cold War prompted the rapid development of Satellite launch systems and camera technology capable of sufficient Earth observation to garner intelligence on enemy military infrastructure and evaluate nuclear posture.{{Cite web |title=Cold War in Space: Top Secret Reconnaissance Satellites Revealed |url=https://www.nationalmuseum.af.mil/Visit/Museum-Exhibits/Fact-Sheets/Display/Article/195923/cold-war-in-space-top-secret-reconnaissance-satellites-revealed/ |website=nationalmuseum.af.mil}} Following the U-2 incident in 1960, which highlighted the risks of aerial spying, the U.S. accelerated surveillance satellite programs like CORONA. Satellites largely replaced aircraft overflights for surveillance after 1960.{{Cite journal |last=Muszyński-Sulima |first=Wawrzyniec |date=2023-06-30 |title=Cold War in Space: Reconnaissance Satellites and US-Soviet Security Competition |url=https://journals.openedition.org/ejas/20427 |journal=European Journal of American Studies |language=en |volume=18 |issue=2 |doi=10.4000/ejas.20427 |issn=1991-9336}}

{{Main|Weather satellite}}

{{See also|Satellite temperature measurements}}

File:GOES 8 Spac0255.jpg, a United States weather satellite.]]

A weather satellite is a type of satellite that is primarily used to monitor the weather and climate of the Earth.NESDIS, [http://www.nesdis.noaa.gov/satellites.html Satellites.] {{Webarchive|url=https://web.archive.org/web/20080704195947/http://www.nesdis.noaa.gov/satellites.html |date=2008-07-04 }} Retrieved on 4 July 2008 {{PD-notice}} These meteorological satellites, however, see more than clouds and cloud systems. City lights, fires, effects of pollution, auroras, sand and dust storms, snow cover, ice mapping, boundaries of ocean currents, energy flows, etc., are other types of environmental information collected using weather satellites.

Weather satellite images helped in monitoring the volcanic ash cloud from Mount St. Helens and activity from other volcanoes such as Mount Etna.NOAA, [http://www.spaceref.com/news/viewpr.html?pid=15216 NOAA Satellites, Scientists Monitor Mt. St. Helens for Possible Eruption.] {{Webarchive|url=https://archive.today/20120910225555/http://www.spaceref.com/news/viewpr.html?pid=15216 |date=2012-09-10 }} Retrieved on 4 July 2008 {{PD-notice}} Smoke from fires in the western United States such as Colorado and Utah have also been monitored.

File:Blue Marble 2002.png]]

Other environmental satellites can assist environmental monitoring by detecting changes in the Earth's vegetation, atmospheric trace gas content, sea state, ocean color, and ice fields. By monitoring vegetation changes over time, droughts can be monitored by comparing the current vegetation state to its long term average.NASA, [http://earthobservatory.nasa.gov/Drought/ Drought.] {{webarchive |url=https://web.archive.org/web/20080819121047/http://earthobservatory.nasa.gov/Drought/|date=19 August 2008}} Retrieved on 4 July 2008 {{PD-notice}} For example, the 2002 oil spill off the northwest coast of Spain was watched carefully by the European ENVISAT, which, though not a weather satellite, flies an instrument (ASAR) which can see changes in the sea surface. Anthropogenic emissions can be monitored by evaluating data of tropospheric NO₂ and SO₂.{{cn|date=March 2024}}

These types of satellites are almost always in Sun-synchronous and "frozen" orbits. A Sun-synchronous orbit passes over each spot on the ground at the same time of day, so that observations from each pass can be more easily compared, since the Sun is in the same spot in each observation. A "frozen" orbit is the closest possible orbit to a circular orbit that is undisturbed by the oblateness of the Earth, gravitational attraction from the Sun and Moon, solar radiation pressure, and air drag.{{cn|date=March 2024}}

Terrain can be mapped from space with the use of satellites, such as Radarsat-1Grunsky, E.C. [https://ieeexplore.ieee.org/document/1024985/ The use of multi-beam Radarsat-1 satellite imagery for terrain mapping.] Retrieved on 4 July 2008 and TerraSAR-X.

File:RapidEye Satellites Artist Impression.jpg Earth exploration-satellite system in action around the Earth.]]

According to the International Telecommunication Union (ITU), Earth exploration-satellite service (also: Earth exploration-satellite radiocommunication service) is – according to Article 1.51 of the ITU Radio Regulations (RR)ITU Radio Regulations, Section IV. Radio Stations and Systems – Article 1.51, definition: earth exploration-satellite service / earth exploration-satellite radiocommunication service – defined as:

A radiocommunication service between earth stations and one or more space stations, which may include links between space stations, in which:

• information relating to the characteristics of the Earth and its natural phenomena, including data relating to the state of the environment, is obtained from passive or active sensors on satellites;
• similar information is collected from airborne or Earth-based platforms;
• such information may be distributed to earth stations within the system concerned;
• platform interrogation may be included.

This service may also include feeder links necessary for its operation.

This radiocommunication service is classified in accordance with ITU Radio Regulations (article 1) as follows:{{cn|date=March 2024}}

Fixed service (article 1.20)

• Fixed-satellite service (article 1.21)
• Inter-satellite service (article 1.22)
• Earth exploration-satellite service
• Meteorological-satellite service (article 1.52)

The allocation of radio frequencies is provided according to Article 5 of the ITU Radio Regulations (edition 2012).ITU Radio Regulations, CHAPTER II – Frequencies, ARTICLE 5 Frequency allocations, Section IV – Table of Frequency Allocations

In order to improve harmonisation in spectrum utilisation, the majority of service-allocations stipulated in this document were incorporated in national Tables of Frequency Allocations and Utilisations which is with-in the responsibility of the appropriate national administration. The allocation might be primary, secondary, exclusive, and shared.

• primary allocation: is indicated by writing in capital letters (see example below)
• secondary allocation: is indicated by small letters
• exclusive or shared utilization: is within the responsibility of administrations

However, military usage, in bands where there is civil usage, will be in accordance with the ITU Radio Regulations.

; Example of frequency allocation:

{{main cat|Earth observation satellites}}

• Committee on Earth Observation Satellites
• Data collection satellite
• Earth observation
• Earth observation satellites transmission frequencies
• Earth Observing System - a NASA program comprising a series of satellite missions
• First images of Earth from space
• Phi Lab
• Imaging satellites
• List of Earth observation satellites
• Space telescope
• Satellite imagery
• GNSS radio occultation
• Microwave radiometer#Spaceborne
• Radar earth observation satellite
• Radar imaging
• Synthetic-aperture radar
• Interferometric synthetic-aperture radar
• Satellite altimetry

{{Reflist}}

• [https://directory.eoportal.org/web/eoportal/satellite-missions EO Portal directory] {{Webarchive|url=https://web.archive.org/web/20130923090413/https://directory.eoportal.org/web/eoportal/satellite-missions |date=2013-09-23 }}
• [https://web.archive.org/web/20160406191132/http://www.campevans.org/_CE/html/tiros1-2.html The TIROS I and II Ground Control Station where the first Earth Observing Satellite (TIROS I) sent it first photos]

{{Spaceflight}}

{{Authority control}}

{{DEFAULTSORT:Earth Observation Satellite}}

Category:Satellites by type

Category:Satellite imagery

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