Disposal and First Satellites

Depending on the mission of a satellite, it will eventually be no longer useful. Some satellites end their useful life when falling out of orbit and burning up in the atmosphere. Others continue to orbit the earth long after the mission has ended.

Depending on the altitude of the orbit, a satellite will either stay in orbit or fall back to earth. Below 1000 km (620 miles) satellites experience friction from the atmosphere which slows them down and because of that the altitude of the orbit decreases until eventually the satellite falls out of orbit and plunges back to earth where it burns up in the atmosphere. Heavy but small satellites maintain their orbits longer than light, but big satellites. A higher mass has more kinetic energy than a small mass, so more friction is needed to slow the satellite down. (it is like a big heavy cargo train, it just stops much slower than a normal car).

The First Satellites

In 1957 the Soviet Union launched successfully the first satellite (Sputnik) that orbited the earth. Sputnik had an elliptical orbit with a minimum altitude of 225 km (140 miles) and a maximum altitude of 900 km (559 miles). It stayed in orbit for about 3 months after which is fell back to earth and burned up in the atmosphere.

The USA successfully launched its first satellite (Explorer 1) in 1958. The orbit was very much more elliptical with a minimum altitude of 360 km (224 miles) and a maximum altitude of 2500 km (1553 miles). During this first mission scientists discovered the Van Allen Radiation Belts; zones in space around the earth, and the planets Jupiter and Saturn, containing high-energy protons and electrons.

In 1960 the USA launched a satellite that brought with it the first artificial object that was ever recovered from space. The satellite rejected a capsule which fell back to earth and was later recovered. This mission led the way to photos of the earth taken from a satellite to be recovered.

Current Count of Satellites

Because of the many launched of satellites (over 4800) the earth is now surrounded by artificial debris. This debris ranges from small objects like astronauts gloves and tools to very big objects like obsolete satellites and used rocket parts. There have been over 25.000 individual objects cataloged of which over 8000 are still in orbit. The rest fell back to earth and burned up in the atmosphere.

There is a good reason for cataloging all space debris. When a satellite launch is planned the path of the satellite is known and is checked against the catalog of space debris. You can imagine that a collision with an old part of a previously launched rocket would be disastrous. But even collisions with relatively small debris can cause huge problems. A screwdriver in orbit can have a speed of 27.000 km (16.777 miles) per hour. If this tiny screwdriver hits the space shuttle for instance it will blast a hole in the shuttle, killing all people inside. Space debris is actually becoming a problem especially for missions in low earth orbit.

By Gary Davis
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Webmasters: You may reprint this article in its entirety, providing you leave the Byline and About the Author sections intact, including the links to Dish Network Satellite TV.

About The Author

Gary Davis is the owner of Dish Network Satellite TV, has several years experience in the Satellite TV Industry and has written numerous articles about satellite TV.

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Email: customerservice@dish-network-satellite-tv.ws Types of Satellite TV Systems – TVRO and DBSGary Davis

In the USA there are 2 types of satellite TV systems. The first is TVRO which stands for TeleVision Receive Only. The second is DBS which stands for Direct Broadcast Satellite.

TVRO – TeleVision Receive Only

TVRO was the first satellite system available for home viewing of satellite TV. It required a relatively big dish of 3 to 6 feet in diameter and worked in C-Band. Frequencies of around 4 G Hertz are called C-Band and require bigger dishes because the wave length of these frequencies is longer than in Ku-Band which requires a much smaller dish of about 18 inches. Ku-Band is at 12 to 14 G Hertz.

TVRO systems also need a movable dish because it needs to get all the channels of many satellites. C-Band satellites have much less channels available than Ku-Band satellites and therefore more satellites are needed to provide enough channels. Possibilities that exist with TVRO systems is that you can also receive free channels and independent feeds from for instance news companies. You could for instance receive the unedited material that is broadcasted from a news crew somewhere in the coverage area of the satellite. They transmit their materials to their headquarters using a C-Band satellite. Many of these types of feeds are not scrambled and are available to everyone with the proper equipment.

TVRO systems are often referred to as Big Dish TV, C-Band Satellite TV and BUD (Big Ugly Dish).

DBS - Direct Broadcast Satellite

Satellite TV via DBS is done in the Ku-Band. These satellites work on higher frequencies and can transmit higher power signals. This means that much smaller dishes can be used to receive the signal. A small dish of 18 inches is already enough to receive all satellite TV by Satellite TV. This makes it possible to have satellite TV from an apartment on the 10th floor, if you have a clear line of sight to the south.

DBS is for everyone. The satellite dish is so small that it is not an obstacle like with for instance the TVRO dishes of 3 to 6 feet. Once installed the dish needs no maintenance since it is aimed at just one satellite. Some dishes actually have 2 or more feeds which makes it possible to receive the signals from more than 1 satellite.

There are no free channels available on DBS satellites as these are often owned and used by the satellite TV provider it self, while TVRO satellites often are used by those who rent space on the satellite for a limited time. TVRO systems are meant for, for instance, transport of unedited materials between continents, but also within one continent.

DBS is meant for everyone with a simple, low cost installation of the system. Often the installation is for free as it really is very easy to do. The only thing that is needed is a bit of knowledge of where to find the satellite and the tools that make this even easier. A qualified installer will find the satellite and point it to maximum reception within minutes.

By Gary Davis
Dish-Network-Satellite-TV.ws

Webmasters: You may reprint this article in its entirety, providing you leave the Byline and About the Author sections intact, including the links to Dish Network Satellite TV.

About The Author

Gary Davis is the owner of Dish Network Satellite TV, has several years experience in the Satellite TV Industry and has written numerous articles about satellite TV.

Dish-Network-Satellite-TV.ws

Email: customerservice@dish-network-satellite-tv.ws