|Název drah||Vzdálenost od povrchu Země|
|Nízké dráhy||160 až 2 000|
|Střední dráhy||2 000 až 34 780|
|Mezinárodní vesmírná stanice - IIS ...||500|
|Global Positioning system - GPS ...||20 230|
|Geostacionární dráha||35 794|
|Hřbitov geostacionárních satelitů||nad 35 900|
|Satellites are carried into orbit by shuttles, where
they go through a process of being launched. Shuttles
flying into an orbit are inclined at 28.5 degrees to the
Equator (Broad, A22). Even though a good number of
satellites are carried into orbit by space shuttles, most
satellites are carried by rockets. The rockets fall back
into the ocean after they have launched the satellite and
their fuel has run out. Sometimes they are retrieved and
are used for other launches. Rockets have the capability
to put satellites into orbit which are 120 miles above the
Earth. Satellites which need to be put into higher orbits
are first put into one orbit around the Earth and then
with their motors, are pushed into higher orbits.
Even before some satellites reach space, 1 in 20 are rendered useless by either being jolted on lift-off, perish in fires of defective rocket blasts or are put into improper orbits (Canby, 282).
The life span of satellites depends largely on their size , or to be precise , it depends on how much liquid fuel they carry aboard , the liquid fuel is used to operate small rocket engines , the rocket engines are very important for the satellite (there are three types of forces acting on the satellite in space causing the satellite to deviate from its course) , the ground station on earth uses these small rockets to perform maneuvers necessary to keep the satellite in the same position in the sky (usually they perform two maneuvers every two weeks, north-south maneuver & east-west maneuver) so we can direct our antenna's here at earth(parabolic reflectors or dish) to this specific point in space & receive the broadcasted TV & radio channels & also to send telecommands from the ground station on earth to control the satellite , otherwise we need a special type of antenna's (half a billion US$ each) to track & locate the satellite , the largest satellites out there are the communication satellites (tv,radio,telephony) & they use the geostationary orbit (about 36,000 km above sea level & above the equator) & i should note that the satellite orbit around the earth depends on the speed of the satellite , once the satellite is delivered to its orbit by the rocket it was carried on, the satellite will take that orbit speed , comm. sat. also have the longest life span (it’s a round 20yrs these days) , before the satellite runs out of fuel , the ground station performs one last maneuver to send the satellite to a place called (the satellite graveyard) , it’s an orbit around the earth used to retire old useless satellites & they become junk on space , a growing problem , this is when in it come to satellites using the geostationary orbit , for satellites using lower orbits they may be put on re-entry course so they burn before they reach the earth.
Ideally (unless there is a technical failure), just before satellite end-of-life, the owner will dispose of it. Disposal generally comes in two forms: re-entry maneuver to allow it to burn up in the atmosphere or maneuver to a "graveyard" orbit (as established by international standards). The caveat would be if you are China...in which case you recklessly increase the amount of space debris by 30% by testing an anti-satellite weapon (and hope that some of that debris deorbits within the next 100 years).
By international treaty, space vehicles and satellites are generally supposed be designed to safe themselves so residual fuels and other stored energy (i.e., batteries, fuel cells, RTGs, etc.) are precluded from causing the vehicle to explode or break apart. Exploding rocket stages and satellites (caused by dead or dying controls allowing residual propellants to react) have historically been a big contributor to orbital debris problems ("space junk").
GSO satellites are supposed to be designed and operated such that right before they are about to run out of usable propellant, they raise their orbits by enough to get them out of the geostationary orbit belt and thus out of the way of the rest of the sats and any replacement vehicles. They don't usually have enough fuel to lower their orbits much and almost certainly wouldn't have enough to totally deorbit. Lowering the orbit also clutters up the transfer orbits needed for replacements. So they go higher up to die, a "graveyard orbit."
So they can hold in this "graveyard orbit" and not descend back through the Clarke Belt at any time? I think the assumption among outsiders is that all orbits decay and eventually, everything will re-enter the Earth's atmosphere.
From a bit of internet research, it supposedly takes a
few hundred years to decay from graveyard orbit to
geostationary, and longer still to reenter the
atmosphere. Sounds like we'll have a signficant problem
on our hands in couple hundred years as the dead
satellites begin to interfere with the active ones. Hope
our kids figure out how to deal with it.
Satellites in orbit might be killed on purpose while
others need to be rescued to get repaired. Since
satellites can cause interference with other orbits or
are just not needed anymore, countries such as the
United States and the Soviet Union have taken actions to
kill these satellites. The United States uses a F-15
fighter which fires a two stage missile at it's target,
the satellite. Using telescopes as it's eyes, the 50
pound warhead adjusts it's flight path so that it might
intercept the path of the satellite. The Soviet Union
uses a heavy satellite, the hunter-killer, which is
boosted to the same orbital path as the target
satellite. The hunter-killer, when in the same orbit as
the target satellite , closes in and explodes destroying
the target satellite (Canby, 333). Satellites in need of
repair and rescue are assisted by shuttles while the
satellites are in low orbits. Many satellites get
repaired while other satellites in the wrong orbit get
returned to Earth to be launched into the correct orbit
or to be repaired.