There is such a fine line between science fiction and actual science. Many of the ideas expressed in science fiction lead to truly amazing scientific findings. Mostly known for his masterpiece 2001: A space OdysseyArthur also served in the Royal Air ForceWhile serving he wrote a paper titled “Extra Terrestrial Relays – Can Rocket Stations Give World Wide Radio Coverage?” was published in wireless world in October 1945.Quote:A true broadcast service, giving constant field strength at all times of the whole globe would be invaluable, not to say indispensable, in a world society.” Because of his visionary approach to communications the geostationary orbit (GEO) is also known as the Clarke Orbit / Clark Belt
Can anyone tell me what this is?Sputnik 1 became the first successful satellite launch on October 4, 1957. Roughly the size of a beach ball it weighed 183.9 lbs.It could orbit the entire earth in 98 minutesSputnik program wasn’t purely communications, but the effects brought on by the program are why we have a broad satellite foundation today. Because of sputnik NASA was formed in October of 1958 when Congress passed the Aeronautics and Space Act
In 1559 Huges Aircraft Company identified the key elements needed in a lightweight active repeater that could be used as a communications satellite.This device would be launched from a ground station (will be discussed later) and come to rest in GEO.Dr. Rosen was the projects engineerTom Hudspeth provided microwave inciteDon Williams identified the way the satellite would be placed into orbit.1960 the prototype was completed and they convinced NASA to launch SYNCON (Synchronous orbit communications satellite) The first attempt didn’t go so well for the team.1963 SYNCON II the team got it right and successfully launched the satellite into spaceThey just provided the foundation for a new industry of communications.
Low Earth Orbit LEOAltitudes between 500 and 2000 kmOrbit periods between 1.6 and 1.8 hours (the higher the orbit the slower the period)So Close: atmospheric drag Because they are so close: they need far less power for transmission with the earth, but need a large network of satellites to provide coverage.Concern: congestion / collision at orbital velocities can be dangerous, highly damaging, and even cause more debris (Kessler Effect)
Medium Earth Orbit (MEO)Can’t operate from 2000 to 8000 feet (Van Allen radiation belt) (draw a picture)high energy particles and cosmic rays.Up to 18000 km This elevation leads to more transmission distance / thus more propagation delay but can require much less power than a GEO satellite for transmissionMore realistic example of the empire state building
Geostationary Earth OrbitElevations around…My puppy (which is much larger now) can demonstrate that many in fact (?) could stand on one another and just then reach that altitude. These satellites maintain a precise synchronization with the Earth’s rotation.Each satellite is positioned roughly 120 degree apart.One need tidbit: A single geostationary satellite could provide coverage for an entire hemisphere at one time.
Three forms of connectivity when dealing with communications satellites.
Mobile / Wireless Communications
Large Coverage Area
Independent of Terrestrial Infrastructure
Low Cost for adding ground sites
Services from a single provider
Voice Quality / Eco
High Initial Investment