Satellite facts and information

A collection of interesting and not so interesting satellite facts and information.

Satellite Facts Includes:
Satellite facts

There are many satellites in orbit fulfilling a huge variety of functions. Satellite technology has now become a part of everyday life, enabling worldwide communications, global navigation, surveying and monitor as well as gathering data for weather forecasting, and many more applications.

There are many facts associated with satellites that are both interesting and useful. Often the facts about these satellites and satellites in general may not be obvious.

We have compiled a page of interesting satellite facts as an introduction to satellite technology.

Facts about numbers of satellites in orbit

Fact	Details
Number of satellites	Over 2 500 in orbit around the Earth
First rockets that entered outer space	The German V2 rocket in mid 1940s
Number of man-made objects orbiting the Earth	In excess of 10 000

Facts about satellite firsts

Fact	Details
First fictional depiction of satellite	The first mention of the idea of a satellite in a fictionals tory occurred in a short story by Edward Everett Hale, The Brick Moon. This story appeared in a publications entitled" The Atlantic Monthly". The serialisation started in 1869
First treatise on the use of satellites	The idea of a satellite was first postulated Konstantin Tsiolkovsky (1857-1935). In 1903 he published an academic paper entitled: " Means of Reaction Devices." In this he proposed the idea of a multi-stage rocket using liquid hydrogen and oxygen being used to launch the satellite into orbit as well as calculating the orbital speed required to maintain orbit as 8 km/s.
First concept of a space station	This occurred in 1928 when the Slovenian scientist, Herman Potocnik (1892-1929) published a book entitled: "The Problem of Space Travel - The Rocket Motor." In this he devised a scheme for establishing a permanent human presence in space. He developed the concept for the space station in some detail and calculated its geostationary orbit. He then went on to describe the use of orbiting spacecraft for observation of the ground for both commercial and military applications.
First detailed concept of geostationary communications satellites	This appeared in an article in 1945 in a British magazine entitled Wireless World. Although written by the famous English science fiction writer Arthur C. Clarke (1917-2008) it postulated the concept of communications satellites to be used for mass communications. Clarke investigated many aspects of the system from the satellite launch, possible orbits and other aspects of the creation of a network of world-circling satellites. He also correctly suggested that just three geostationary satellites would provide coverage over the entire planet. Unfortunately he did not realise quite how much the system would be used, and that many more satellites would be required to cater for the huge volume of data.
First satellites	Sputnik 1 was launched by the Soviet Union on 4th October 1957. It was a football sized globe that transmitted a "beep beep" sound as it orbited the Earth. The word Sputnik means satellite. It continued transmitting for about 21 days.
Second satellite	Explorer 1 launched 31st January 1958 by USA.
First passive reflector satellite	Echo 1 - launched by the USA on 12 August 1960. It was used as a large reflector for radio signals, and was also plainly visible from Earth to the naked eye
First active repeater communications satellite	Courier 1B - this was launched on 4 October 1960. It was also the first satellite powered by solar cells that were used to re-charge batteries used to power the system when behind the earth.
First direct relay communications satellite	Telstar 1 - launched on 10 July 1962, it carried the first transatlantic live television pictures via satellite. It was also used for telephone and high speed data communications.
First communications satellite in geostationary orbit	Syncom 2. This was launched on 19 August 1964. It carried the first Olympic broadcasts to international audiences via satellite. These Olympics were held in Tokyo.

Facts about satellite orbits

Fact	Details
Geostationary orbit	An orbit in which the satellite has the same angular velocity as the Earth so it appears above the same position above the Earth at all times. These orbits can only be directly above the equator.
Geostationary orbit altitude	Approximately 35 786 km, 22 236 mile
Geostationary orbital velocity	Approximately 3.07 km/s, 1.91 miles/s
Geostationary orbital period	1 sidereal day, 23.934461223 hours, 23 hours 56 minutes and 4 seconds, 1 436 minutes 4 seconds.
Geostationary orbit distance	The distance around the path of a complete geostationary orbit is approximately 265 000 km or 165 000 miles
Low Earth Orbit, LEO altitude range	200 - 1200 km
Medium Earth Orbit, MEO altitude range	1200 - 35790 km
High Earth Orbit, HEO altitudes	Above 35790 km

Facts about the satellite navigation

Fact	Details
Most widely used SatNav	GPS - Global Position System
GPS official Name	Navstar
GPS operator	US Department of Defense
Navstar constellation	24 satellites + orbiting spares
Navstar satellite expected life-time	10 years
Navstar typical size	Dependent upon the satellite series and build date, but typically 17 feet across with antennas extended
Navstar typical weight	Dependent upon the satellite series and build date, but can be around 1860 pounds.
Navstar transmit power	~ 50 watts
Navstar solar panel capability	Solar panels generate about 700 watts of electricity
Navstar orbits	The satellites are in one of six orbits. These are in planes that are inclined at approximately 55 degrees to the equatorial plane and there are four satellites in each orbit. The orbits that are roughly 20200 km above the surface of the Earth.
Navstar satellite speed	Approximately 14000 km / hour, 8500 mph
Navstar orbit time	Approximately 12 hours

Direct broadcast satellite facts

Fact	Details
Name	Although commonly called Direct Broadcast Satellite, DBS, it is officially known by the International Telecommunication Union, ITU, as Broadcasting Satellite Service, or BS. It is a direct to home, DTH service
Frequency bands	*ITU Region 1 (Europe, Russia, Asia):* 10.7 - 12.75 GHz *ITU Region 2 (North & South America):* 12.2 - 12.7 GHz *ITU Region 3 (Asia, Australasia):* 11.7 - 12.2 GHz