The first operational #optical #communication line arrived in 1792, covering #France
with a network of 556 stations stretching a total distance of 4,800 km https://en.wikipedia.org/wiki/Optical_communication#Semaphore_line
Picture : #NASA's #Mars #Telecommunications #Orbiter * https://commons.wikimedia.org/wiki/File:PIA07499.jpg
* successor : Key features #SolarElectric #IonDrive engines, broadband #LaserCommunication (optic communication) between #Earth and #Mars https://en.wikipedia.org/wiki/Next_Mars_Orbiter