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The 10-Year Satellite Forecast
coondoggie writes "When it comes to satellites sometimes less is more. In the next ten years the government expects to see fewer but ever larger satellites flung into space. Specifically, the folks who monitor such things, the Commercial Space Transportation Advisory Committee (COMSTAC), said in a draft report today that an average 20.8 satellites could be launched from 2009 through 2018, a decrease of one satellite when compared to the 2008 forecast of 21.8 and the 2007 forecast of 21.0 satellites per year. Actual launches per year were above 20 for the first time since 2002 and the highest total since 2000, with 23 satellites launched in 2008.
As for the weight, the group said there has been steady growth in satellite mass since 1993 and the trend will continues as satellite mass is expected to remain near or slightly above 100,000 kilograms (220,400 lbs) forecast for the coming years with an all-time high of nearly 116,500 kg (257,000lbs) in 2009, the COMSTAC report stated."
We don't put many 100,000kg mass payloads into orbit anymore... if we ever have. Unless the entire shuttle counts.
Congestion in geosynchronous orbit is definitely a problem for bandwidth. Satellites rely on tight beams to save on frequencies. But as has been pointed out previously, space is big. Really, really big.
GSO has a radius of 42,164 km. And a circumference of 132479 km. So if you had a bird every 10km there would be space for 13247 of them, which sounds pretty good to me.
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At end-of-life, geostationary satellites are moved into a higher orbit to make way for new ones.
Or do they assume that they will just fall to Earth, or drift off into space?
Actually, they do get rid of old satellites. These days many satellites are built with small rockets that are used to de-orbit them at the end of their useful life. Alternatively, they are boosted into a higher "graveyard" orbit.
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Well, it's not so much about linear spacing as angular elbow-room. Considering the 1-dB beam width at 14 GHz is around 0.7 degs, you could have ~500 orbital slots assuming they're all on the same frequency (no reusage). Still, you'd have some 500 km for each, enabling you to can cram some more with the reusage thing-y.
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geo satellites orbit the equator.. you can't have one orbit the "poles."
Think about logistics here. How expensive is it to launch a new comm or earth imaging satellite? Then, how expensive is it to launch HUMANS to the same altitude with repair tools and all of the consumables they require to get up and down safely.
When you add the fact that the tech up there is still advancing very rapidly, I don't think there's very much benefit in trying to create these super multi-purpose birds.
And when there is (like Hubble, whose time IS portioned out as you mentioned and a replacement costs ridiculous sums of money), repairs can and do happen.
To further clarify this, there ARE polar orbit satellites, but, the problem is that while they are orbiting on a North-South trajectory, the Earth is spinning West-East. This makes it difficult for communications satellites because unless the orbit is perfectly synchronized with the Earth's rotation, which is difficult due to an irregularly shaped planet, axis tilt, elliptical orbits resulting in weird apogees, etc., then when the sat passes over, it's in a different spot every day. Geosynchronous orbit sats are always in the same spot spinning with the Earth at the same speed; very easy to tell your antenna to look at a fixed point in space.
So, the highly prized areas you are referring to are for communication satellites, and to a slightly lesser degree, television satellites.
North America and Europe are the two largest markets, but you're discounting Asia rather heavily.
To optimize the satellite's placement in relation to population density, you'll find sats towards the West side of the Atlantic, over the equator, serving the eastern seaboard of the U.S. along with the eastern part of South America and the Caribbean. Sats over the Atlantic towards the East will service western Europe and western Africa. Sats placed over the Indian ocean will service Southeast Asia, the Middle East, East Africa and western Australia. Sats over the Pacific will service East Asia (China, Japan) and the eastern seaboard of Australia, along with the west coasts of North and South America.
There is some overlap. For example, I can tune into AOR-W (Atlantic Ocean Region - West) or IOR (Indian Ocean Region) sats while I'm in the Mediterranean, but, I generally get the best reception on AOR-E due to it's location over the east Atlantic.
Polar orbit sats are still used, but they are not optimal due to most population centers in the world being near the equator, and you would need several sats in the same loop for 24/7 operation, as when your antenna tracked the satellite falling off the southern horizon, it would need another sat rising in the north to retune to.
This isn't a prob for the geosynch'd sats.
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Jebus. Of course they orbit. They just happen to have an orbital velocity that matches the rotational velocity of earth.