Editing Reconnaissance satellite (section)

== Types ==
There are several major types of reconnaissance satellite.<ref>{{citation |url=http://www.infoplease.com/encyclopedia/science/reconnaissance-satellite.html |title=reconnaissance satellite |publisher=Infoplease |access-date=2014-02-17}}</ref>

;Missile early warning
{{main|Defense Support Program|Space-Based Infrared System}}
:Provides warning of an attack by detecting [[ballistic missile]] launches. Earliest known are [[Missile Defense Alarm System]].{{citation needed|date=September 2019}}

;Nuclear explosion detection
:[[nuclear detonation detection system|Detects nuclear detonation]] from space. [[Vela (satellite)|Vela]] is the earliest known.{{citation needed|date=September 2019}}

;Electronic reconnaissance
:[[Signals intelligence]], intercepts stray [[radio]] waves. [[SOLRAD]] is the earliest known.<ref name=spy>{{cite web|url=https://www.usni.org/magazines/naval-history-magazine/2008/april/navys-spy-missions-space|title=The Navy's Spy Missions in Space|date=April 2008|publisher=U.S. Naval Research Laboratory|access-date=21 April 2019|archive-url=https://web.archive.org/web/20190421145952/https://www.usni.org/magazines/naval-history-magazine/2008/april/navys-spy-missions-space|archive-date=21 April 2019|url-status=live}} {{PD-notice}}</ref>

;Optical imaging surveillance
:[[Earth imaging satellite]]s. [[Satellite images]] can be a survey or close-look [[Telephoto lens|telephoto]]. [[Corona (satellite)|Corona]] is the earliest known. [[Spectral imaging]] is commonplace.

;Radar imaging surveillance
:Most [[space-based radar]]s use [[synthetic-aperture radar]].{{citation needed|date=September 2019}} Can be used at night or through [[cloud cover]]. Earliest known are the Soviet [[US-A]] series.