Satellite

A satellite is a man-made object which has been intentionally placed into orbit.

HISTORY

In the 16th century, the word "satellite" meant "an attendant on a person of importance." The following century, it came to be used for a small planet revolving around a larger one.

The English science fiction writer Arthur C. Clarke described in detail in a 1945 Wireless World article, the possible use of communications satellites for mass communications. He suggested that three geostationary satellites would provide coverage over the entire planet.

On October 4, 1957, the first man-made satellite, Sputnik 1, was launched into orbit by the Soviet Union. Sputnik 1 was about the size of a beach ball and took about 98 minutes to orbit the Earth.

Sputnik 1: The first artificial satellite to orbit Earth.

Model Sputniks were among gifts given by the Soviet government to UK Prime Minister Mr Harold Macmillan and Mr Selwyn Lloyd, Foreign Secretary, on March 3, 1959 during a visit to Moscow. They played the Soviet national anthem, punctuated by a ‘Beep, beep, beep’ — the sound of the three real Sputniks.

Sputnik's launch is marked every year by World Space Week from October 4-10, a “celebration of science and technology, and their contribution to the betterment of the human condition”.

Launched on March 17, 1958, Vanguard 1 is the oldest satellite still orbiting the Earth. Weighing only 3.2 pounds and with a diameter of 6.5 inches, Soviet Premier, Nikita Khrushchev, derided it as "the grapefruit satellite".

Vanguard 2 was the second satellite launched by the United States, and it was specifically designed to study the Earth's cloud cover distribution. It was launched on February 17, 1959, and it orbited the Earth once every 134.2 minutes.

Vanguard 2 was equipped with two cameras that took photographs of the Earth's cloud cover, and it was able to transmit these images back to Earth using radio signals. The satellite was also equipped with a set of temperature sensors, which helped scientists to better understand the relationship between cloud cover and temperature.

Explorer I, the first American satellite, was launched on January 31, 1958, four months after Sputnik I, beginning the so-called space race. Although it carried a number of instruments, Explorer I was relatively small, weighing just 30 lbs (13 kg).

Explorer 1 satellite

Explorer I stopped transmission of data later in 1958, when its batteries died, but remained in orbit for more than 12 years.

SCORE was the world's first communications satellite, launched by the United States on December 18, 1958. It was developed by the U.S. Army Signal Corps and was designed to transmit telephone calls, television pictures, and other data between the United States and Europe. SCORE was the first satellite to be used for commercial communications, and it helped to pave the way for the development of satellite television and the internet.

In 1961, a Soviet satellite called Sputnik 3 crashed into a cow pasture in Cuba. The satellite was about the size of a refrigerator and weighed about 2 tons. The cow was killed instantly. This is the only documented case of a satellite crash fatality.

The 34 inch spherical communications satellite Telstar 1, backed by John F Kennedy, was launched, paving the way for live broadcasting from thousands of miles away.

The first historic ‘space-vision’ pictures to be transmitted directly across the Atlantic flashed onto British TV screens at 1am on July 11, 1962. Viewers saw the pictures — relayed from America to the satellite Telstar 2,000 miles above the ocean — for 30 seconds.

Telstar

Early Bird, the first communications satellite to be placed in geosynchronous orbit was launched in 1965.

On October 28, 1971, Britain's Black Arrow rocket launched the satellite Prospero into space from Woomera in South Australia. It was the first and only successful orbital launch to be conducted by the United Kingdom. Prospero was an experimental satellite that tested materials and systems that could be used in the manufacture of communications satellites. It also carried a micrometeoroid detector to measure the presence of very small particles in space.

Prospero remained in orbit for over two years, and it collected valuable data on the effects of the space environment on satellites. The data collected by Prospero helped to improve the design of future British and international satellites.

In 1974 the Soviet Union launched Salyut 3, a crewed military satellite armed with a 30mm 'self defence' cannon. It was fired several times and even used to destroy a test satellite in orbit. The Salyut 3 remains the only armed, crewed spacecraft ever flown.

The space station Skylab crashed to Earth in Australia after six years in space in 1979. Leading up to the event, Electric Light Orchestra took out ads in trade magazines dedicating their new single, "Don't Bring Me Down", to Skylab.

When the Skylab re-entry approached the Earth, the San Francisco Examiner offered $10,000 to the first person to deliver a piece to them within 72hrs knowing it wasn't heading toward the USA. A 17-yr-old Aussie collected a piece, jumped on a plane with no passport or luggage and collected his prize.

NASA received a $400 littering ticket  from Western Australia when pieces of Skylab fell on the region. 30 years later a Californian radio DJ raised funds from his listeners and paid NASA’s bill.

On February 10, 2009 two communications satellites, from the US (Iridium 33) and Russia (Kosmos-2251), collided and destroyed each other. It was the first time two man-made satellites had collided by accident.

The communications satellite Meridian 5 was launched on December 23, 2011, with the rocket performing nominally during first and second stage flight. At 288 seconds after launch, the Blok I third stage's RD-0124 engine ignited to begin its burn. During third stage flight, an anomaly occurred which prevented the rocket from reaching orbit. Debris from the launch fell over the Novosibirsk Oblast in Siberia, near Ordynsk. One piece of debris fell through the roof of a house in Cosmonaut Street in the village of Vagaitsevo. Despite debris falling in residential areas, no injuries were reported.

FUN SATELLITE FACTS

The speed a satellite must travel to stay in space is called its orbital velocity. It usually needs to be more than 17,500 mph.

A full-size model of the Earth observation satellite ERS 2

There is a satellite 'Lageos 1′ – which is in orbit and designed to stay up there until it decays in eight  million years with messages for whoever is still around.

Geostationary satellites orbit the equator at the speed of the Earth’s rotation so seem not to move.

Polar satellites’ orbits pass over the poles so scan the whole Earth as it rotates beneath them.

More than 20 satellites make up the Global Positioning System, or GPS, enabling precise positions to be measured at any time.

GPS satellites move at a very high speed, about 4 kilometers per second. This means that they are experiencing time dilation, which is the slowing down of time as seen by an observer who is moving relative to another observer. As a result, the clocks on GPS satellites need to be slowed down by about 45 microseconds per day to account for time dilation.

According to a 2013 estimate, there are now more than 3,600 artificial satellites in orbit around the Earth. Of those, about 1,000 were operational; while the rest have lived out their useful lives and became space debris.

Source Daily Express