WHAT’S ABOVE US?
You may not realize, but there are more than 1,200 active satellites orbiting Earth right this very second.
You may not realize, but there are more than 1,200 active satellites orbiting Earth right this very second.
An artificial satellite is a specialized wireless receiver and transmitter that is launched by a rocket and placed in orbit around the Earth. Satellites come in all shapes and sizes and play a variety of roles.
Sputnik 1 was the first satellite in space launched by the Soviet Union in 1957.
Sputnik 1 helped to identify the density of high atmospheric layers through measurement of its orbital change and provided data on radio-signal distribution in the ionosphere. NASA then launched Explorer 1 in 1958. From there, the space race began and a new way to look at the Earth was developed.
Above is simple illustration of Sputnik 1, it was originally the size of a basketball.
Satellites orbit Earth at different heights, speeds, and paths.
The two most common types of orbit are geostationary and polar. A geostationary satellite travels from west to east over the equator. It moves in the same direction and at the same rate Earth is spinning. From Earth, a geostationary satellite looks like it is standing still since it is always above the same location.
Polar-orbiting satellites travel in a north-south direction from pole to pole. As Earth spins underneath, these satellites can scan the entire globe, one strip at a time.
The Hubble Space Telescope
The International Space Station
Amsat Oscar 7
Surveillance satellites image the Earth's surface and records radio signals for military and government purposes.
They can also be used to detect nuclear explosions and missiles as well as send warning signals. Out of the 1,200 active satellites, only 93 are used for surveillance.
A GPS satellite is used by the NAVSTAR Global Positioning System. These satellites help you know where you are and where to go.
GPS was originally intended for military applications, but in the 1980s, the government made the system available for civilian use. There are currently 103 active GPS satellites.
A meteorology satellite is a primarily used to monitor the weather and climate of the Earth.
They not only track weather but also changes in climate, fires, city lights, effects of pollution, auroras, sand and dust storms, snow cover, ice mapping, boundaries of ocean currents, energy flows etc. There are 39 of them so far.
Communication satellites send radio, television, and telephone transmissions anywhere in the world.
They are often in geostationary orbit and abbreviated as comsat. Communication satellites relay receive signals from an earth station and then retransmits the signal to other earth stations. Today, there are 989 active communication satellites.
Technology satellites contribute to satellite development, space exploration, and much more.
Some technology satellites responsible for many of astronomy's most important achievements. Jupiter's rings, for example, were discovered by a space exploration satellite. There are 167 technology satellites
Below are the countries that own satellites. The top five are the USA, Russia, China, Japan, and the UK.
Overall
United States
Russia
China
Chronology of active satellite launches. The oldest operational satellite data is from 1974 from the Amsat-Oscar 7, an amateur radio satellite released by the USA.
