We know that moon is orbiting the earth due to the gravitational force of attraction between the moon and the earth. By using the same principle, human beings have developed many satellites. In the beginning days, many countries launched their own satellites on experimental basis, but now it is a profitable business.
Sputnik 1
The first artificial satellite or man-made satellite (Sputnik 1) was developed and successfully launched by the Soviet Union on October 4, 1957. This successful launch shocked the whole world. Sputnik 1 caught the world’s attention. This world’s first artificial satellite was about the size of large beach ball and weighed around 184 pounds (83 Kilograms). This launch is marked as the begin of space age.
Sputnik 1 has provided the valuable information to the scientists such as identifying the density of upper atmosphere. It travelled at a speed of 29,000 kilometers per hour around the earth. Sputnik took 98 minutes to complete each orbit around the earth. This launch also led to the creation of American space agency, NASA (National Aeronautics and Space Administration).
Sputnik 2
A month after the launch of Sputnik 1, the Soviet Union launched another satellite Sputnik 2. The second artificial satellite (Sputnik 2) was launched in to orbit on November 3, 1957. Sputnik 2 carried the first living being (dog) named Laika.
Sputnik 2 contained several compartments for telemetry system, a programming unit, radio transmitters, a regeneration and temperature control system for the cabin, and scientific instruments. Laika (dog) was placed in a separate sealed cabin.
Explorer 1
Explorer 1 was the first artificial satellite launched by the United States on January 31, 1958 and it was the worlds third artificial satellite launched in to orbit. Explorer 1 discovered the Van Allen radiation belt. The Van Allen radiation belt is one of the two radiation belts of earth. Radiation belt is a region surrounding a planet where charged particles buildup under the influence of planets magnetic field.
Explorer 2
Explorer 2 was the second explorer series satellite developed and launched by the United States on March 5, 1958. However, due to failure in the rocket during launch, the satellite failed to reach the orbit.
Vanguard 1
Vanguard 1 was the world’s fourth artificial satellite launched in to orbit on March 17, 1958. It was the second successful artificial satellite launched by United States. It was weighed around 1.47 kilograms. Vanguard 1 was the first satellite that used solar power. It was designed to test the launch capabilities of a three-stage launch vehicle.
Explorer 3
Explorer 3 was an artificial satellite launched by United States on March 26, 1958. It was the third explorer series satellite of the United States. The mission of Explorer 3 is nearly identical to the Explorer 1.
Explorer 3 collected the data about Van Allen radiation belt and confirmed that radiation belts influenced by earth’s magnetic field exist.
Sputnik 3
Sputnik 3 was an artificial research satellite launched by Soviet on May 15, 1958. It explores the near space and the upper atmosphere.
SCORE
SCORE was the world’s first communication satellite launched by United States on December 18, 1958. SCORE stands for Signal Communication by Orbiting Relay Equipment. It captured the world’s attention by redirecting a signal (the recorded Christmas message from president) back to the earth.
TIROS 1
TIROS-1 was the world’s first successful weather satellite launched by United States on April 1, 1960. TIROS stand for Television Infrared Observation Satellite. TIROS-1 mission was to determine if satellites could be useful in the study of earth.
Echo 1
Echo 1 was a communication balloon satellite launched by United States on August 12, 1960. It was designed as a passive communication reflector for transmitting the telephone and radio signals over long distances. The passive communication balloon satellite receives the electromagnetic signal from the source and redirects it back to the earth.
Courier 1B
Courier 1B was the telecommunications recording satellite launched by the United States on October 4, 1960. It will records the messages from an earth station and re-broadcast them.
Ariel 1
Ariel 1 was the first British satellite launched on April 26, 1962. It was designed to contribute to the current knowledge of the ionosphere and of sun-ionosphere relationships. Ionosphere is the layer of earth atmosphere that contains high concentration of free electrons and ions.
Telstar 1
Telstar 1 was the world’s first active communication satellite launched by United States on July 10, 1962. It was primarily designed to measure the energetic electron and proton distribution in the Van Allen belts. Telstar 1 is also used to broadcast the television signals. When television signal is send to the Telstar, it receives the signal, amplifies it, and redirects the signal back to the earth.
Alouette 1
Alouette 1 was the Canadian satellite launched on September 29, 1962. It was designed to study the ionosphere.
Many other satellites launched in to the orbit include Relay, Syncom, San Marco, Molniya-1, Asterix, ATS-1, Intelsat-1, Intelsat-2, WRESAT, Intelsat-3, Azur, Ohsumi, Dong Fang Hong, Uhuru, Prospero, Aryabhatta etc.