Editing Earth Observing System (section)

== History and development ==
[[File:TIROS.jpg|thumb|TIROS-1 Satellite displayed at [[National Air and Space Museum]] in Washington]]
Prior to the development of the current Earth Observing System (EOS), the foundations for this program were laid in the early 1960s and 1970s. [[TIROS-1]], the very first full-scale, [[low Earth orbit]] [[weather satellite]].<ref name=":1">{{Cite web |title=TIROS {{!}} Science Mission Directorate |url=https://science.nasa.gov/missions/tiros |access-date=2022-05-11 |website=science.nasa.gov}}</ref> The primary objective of TIROS-1 was to explore [[Television Infrared Observation Satellite|television infrared observation]] as a method of monitoring and studying the surface of Earth. Critical to the development of the satellites currently in use, TIROS-1 was a program that allowed NASA to use experimental instruments and data collection methods to study meteorology worldwide. Crucially, this new information gathered by TIROS-1 would allow meteorologists and scientists to observe large-scale weather events. In doing so, they would be able to answer questions such as  "should we evacuate the coast because of the hurricane?".<ref name=":1" /> Following TIROS, the experimental [[Applications Technology Satellite]] (ATS) program was developed. The main objective of these satellites were weather predictions and the study of the environment of space. Significantly, this program focused on launching satellites to [[Geosynchronous orbit|orbit geosynchronously]] and evaluate the effectiveness of this orbit pattern in observing the Earth.<ref name=":0" /> [[ATS-3]], the longest-lasting mission, saw a life span of over 20 years. It was the first satellite to capture colour images from space and acted significantly as a medium of communications.<ref name=":0" />

After the success of TIROS-1 and ATS-3, NASA in conjunction with [[United States Geological Survey]] (USGS), progressed forward in Earth observation through a series of [[Landsat program|Landsat satellites]] launched throughout the 1970s and 1980s. The Nimbus 5 satellite launched in 1972 used passive microwave imaging; a highly successful method to observe changes in sea ice cover.<ref name=":0" />  Observation was furthered by succeeding missions such as [[Nimbus 7]], fitted with a [[Coastal zone color scanner|coastal zone colour scanner]] (CZCS) for detailing colour changes in the Earth's oceans, and a [[Total Ozone Mapping Spectrometer]] (TOMS) to measure [[solar irradiance]] and the reflected radiance from the Earth's atmosphere.<ref name=":0" /> The early satellites of these programs have paved the way for much of the EOS program today. The [[TIROS|TIROS satellites]] were extremely important in the testing and development of not only the Earth observing instruments such as [[spectrometers]], but much was also learnt from the various sensors used in order to maintain these satellites in orbit for sustainable periods of time. Sensors such as horizons sensors were tested on these early satellites and have been adapted to produce more advanced methods of observation and operating configurations.<ref name=":0" />