How do they launch satellites

How does a satellite get into space?

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Five, four, three, two, one, Ignition! We know the dramatic countdown to the launch of a rocket from Hollywood films. In the series on the topic of satellite technology, this time we look at the journey of a rocket and satellite from Earth into space.

Brilliant rocket launch

Satellites cannot fly into space on their own - they need a launcher or a space shuttle to do so. This is because satellites only have control nozzles to maintain their position or to change orbit.

Astra satellites mostly “travel” into space with Ariane 5 launch vehicles. They have been in use since 1996 and can transport up to 20 tons of payload. Depending on the design, the cargo space of the 50 meter long rocket is around 17 meters long (this corresponds to 200 cubic meters). The forces involved in such a rocket launch are extremely high: around 5.5 meters per second launch acceleration, almost 12,000 kilonewtons launch thrust. The total weight of the rocket at launch is 780 tons. The flight time to the orbital position takes about nine hours, after which the satellite maneuvers out of the hold. The launcher is a disposable product - it burns up when it crashes through the earth's atmosphere.

Most satellites have reached the end of their technical life after about ten to 15 years. Then they are directed into the earth's atmosphere, where they burn up due to the high level of friction. By the way: The oldest satellite ("Vanguard 1") has been in orbit since 1958, although it has not sent any data for 50 years. It is only used for the science of finding out how long a satellite can stay in orbit.

On the way with the rocket

Satellites operate in the orbit of the earth and are “held” in place by their gravitational pull. The so-called geostationary orbit at an altitude of 36,000 kilometers is the ideal location for communications satellites, as they are located there over a fixed point above the equator. Strictly speaking, their orbital time around the earth takes exactly one day - so they rotate at the same speed as the earth. This positioning allows your antennas to be permanently aligned.

Exactly the opposite is desired with spy satellites. You should circle the earth as quickly as possible in order to take current photos at short intervals. In Low Earth Orbit (LEO), at an altitude between 200 and 2,000 kilometers, they only need around 100 minutes to orbit the earth.

Train station into space

A spaceport or cosmodrome is called a rocket launch site. There are around 27 of them worldwide. They are usually as close as possible to the equator, since the launching rockets already receive the maximum centrifugal force from the earth's rotation.

The CSG (Center Spatial Guyanais) station for European satellite projects is in Kourou, French Guyana. The location near the ocean ensures that no human life is endangered in the event of false starts.

Another commonly used spaceport is Baikonur in Kazakhstan. The communications satellite Astra 2E was launched there in autumn last year (but with a Proton M rocket instead of an Ariane 5).

The world's first spaceport was built for military purposes in 1936 on the German island of Peenemünde.

1,200 satellites in space

According to the German statistics institute “statista”, there are currently more than 1,200 satellites for various purposes in space. More than half of them are communication satellites (TV, radio, telephony), around 30 belong to the GPS location system. Another large proportion is accounted for by satellites for meteorology and science.

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