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#11
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What Is Soyuz Using For Comm These Days?
Rand Simberg wrote:
On Tue, 20 May 2008 23:21:16 -0500, in a place far, far away, "Jorge R. Frank" made the phosphor on my monitor glow in such a way as to indicate that: Rand Simberg wrote: Anyone know? Do they have a TDRSS system as part of the ISS agreement? No - they have a TDRSS-like system called Altair, and there may be a satellite or two from that system still running, but Soyuz isn't equipped with an antenna for it. It relies on ground stations for comm, and all the ground stations are in Russian territory. (For that matter, I don't think the Lira antenna on the Zvezda module intended to communicate via Altair was ever fully deployed.) Actually, I got an email response from Oberg: "Mir used to have a TDRSS-like system called 'Luch', and a dish antenna capable of communicating with the GEO relay satellite is installed on the Service Module now linked to ISS. But it's never worked. The old system broke down and wasn't replaced in the 1990's. There are one or two payloads already built, at the Reshetnev plant in Krasnoyarsk, but they won't deliver them until the Russian Space Agency pays cash -- and by now, their components have probably exceed their warranties anyway. The Russians have a voice relay capability through the NASA TDRSS, but can't relay TV or telemetry, so they conduct how-criticality operations such as dockings or spacewalks only when passing over Russian ground sites. They don't even have ocean-going tracking ships any more -- all sold for scrap [one is in drydock as a museum]." Luch and Altair are the same thing. Hate to use Wikipedia as a source, but it was the quickest thing I could find: http://en.wikipedia.org/wiki/Altair_(satellite) |
#12
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What Is Soyuz Using For Comm These Days?
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#13
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What Is Soyuz Using For Comm These Days?
Rick Jones wrote:
In sci.space.history Scott Dorsey wrote: All of Iridium works. The whole constellation isn't up there, but you can pick up the phone anywhere in the world and get a call through. Iridium is pretty heavily used. That got me looking them up on the web - the production rate they achieved with the satelites was impressive if the wikipedia article is at all accurate. Almost like the satellite equivalent to a liberty ship 21 days to make a satellite, one coming off the line every 4.3 days. That starts to sound like "responsive" in the context of some of the other posts in the group. It's pretty hard to call something long planned "responsive" in my book... D. -- Touch-twice life. Eat. Drink. Laugh. http://derekl1963.livejournal.com/ -Resolved: To be more temperate in my postings. Oct 5th, 2004 JDL |
#14
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What Is Soyuz Using For Comm These Days?
Smoke signals? At least it very nearly did no two recent re-entries.
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What Is Soyuz Using For Comm These Days?
On May 21, 7:05*pm, (Scott Dorsey) wrote:
Rick Jones wrote: I wonder how much of Iridium still works, or how many satellite ISP's there are around the globe and how well a "base station" moving across/below them at 17000 MPH would work...assuming the base station kept a dish pointing at one or another of the ISP's satellites in GEO. Terrestar perhaps if it manages to launch? (although that would be NA only I guess) All of Iridium works. *The whole constellation isn't up there, but you can pick up the phone anywhere in the world and get a call through. Iridium is pretty heavily used. Then why is Motorola broke? They bet the farm on Iridium and lost. Surely it isn't making anywhere near the money that cellular is making. There are actually a lot of satellite phone services and ISPs around the globe, but most of them are using satellites that target only a very small area. *Iridium works anywhere, and it's a hell of a lot cheaper than INMARSAT. Why hasn't it replaced cellular service then? Surely satellite phones are better technology than is cellular. If sat phones are so cheap then why do I and millions of others still have cellular phones? Eric |
#16
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What Is Soyuz Using For Comm These Days?
On Thu, 29 May 2008 14:08:23 -0700 (PDT), in a place far, far away,
Eric Chomko made the phosphor on my monitor glow in such a way as to indicate that: On May 21, 7:05*pm, (Scott Dorsey) wrote: Rick Jones wrote: I wonder how much of Iridium still works, or how many satellite ISP's there are around the globe and how well a "base station" moving across/below them at 17000 MPH would work...assuming the base station kept a dish pointing at one or another of the ISP's satellites in GEO. Terrestar perhaps if it manages to launch? (although that would be NA only I guess) All of Iridium works. *The whole constellation isn't up there, but you can pick up the phone anywhere in the world and get a call through. Iridium is pretty heavily used. Then why is Motorola broke? They bet the farm on Iridium and lost. Surely it isn't making anywhere near the money that cellular is making. Motorola isn't broke. They don't operate the system. They did lose a lot of money on it, though. Motorola spent six billion dollars to build the system and ended up selling it to its present owners for twenty-five million. There are actually a lot of satellite phone services and ISPs around the globe, but most of them are using satellites that target only a very small area. *Iridium works anywhere, and it's a hell of a lot cheaper than INMARSAT. Why hasn't it replaced cellular service then? Surely satellite phones are better technology than is cellular. If sat phones are so cheap then why do I and millions of others still have cellular phones? Because it's not better technology than cellular, nor is it cheap. The only advantage of it is that it provides global communications (as long as you're outside). Cells don't have universal coverage. |
#17
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What Is Soyuz Using For Comm These Days?
Eric Chomko wrote:
Then why is Motorola broke? They bet the farm on Iridium and lost. Careful. Don't confuse development costs with operating costs. Iridium cost a great deal to develop and recovering that investment was the problem. Recovering operating costs is much easier. A similar problem beset Concorde. British Airways and Air France were able to cover the operating costs but the British and French taxpayers were forced to eat the development costs. Also, the current Iridium system has been scaled down compared to the initial configuration. In particular, most of the Ka-band gateways were closed leaving just two, one in AZ (for most traffic) and one in HI (for DoD users). Surely it isn't making anywhere near the money that cellular is making. Of course not. There are actually a lot of satellite phone services and ISPs around the globe, but most of them are using satellites that target only a very small area. Iridium works anywhere, and it's a hell of a lot cheaper than INMARSAT. Why hasn't it replaced cellular service then? Surely satellite phones are better technology than is cellular. If sat phones are so cheap then why do I and millions of others still have cellular phones? You might as well ask why 3G wireless data hasn't replaced WiFi. Answer: WiFi works well when our geographic range requirements are very modest and is much cheaper. Only when we need broader coverage do we start buying expensive wide area data services. Satellite phone systems are always going to be more expensive to set up and operate considering that the base stations are in LEO and the link budget is more difficult (due to ranges of hundreds of km vs. a few km). Their main advantage - global coverage - is hard to beat when you're off and away from the terrestrial network, though. -- Dave Michelson |
#18
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What Is Soyuz Using For Comm These Days?
Dave Michelson writes:
Then why is Motorola broke? They bet the farm on Iridium and lost. Careful. Don't confuse development costs with operating costs. Iridium cost a great deal to develop and recovering that investment was the problem. Recovering operating costs is much easier. True... Also, the current Iridium system has been scaled down compared to the initial configuration. In particular, most of the Ka-band gateways were closed leaving just two, one in AZ (for most traffic) and one in HI (for DoD users). And who says it's a success? Hint: Iridium II {or whatever it's called..} is running solely because they have a large USG contract with guaranteed income. Nowhere does it say Uncle Sam is required to use it; just pay as if they did. Or so I'm told by someone watching the game. Their main advantage - global coverage - is hard to beat when you're off and away from the terrestrial network, though. Hence Uncle Sam's willingness to overpay... -- A host is a host from coast to & no one will talk to a host that's close........[v].(301) 56-LINUX Unless the host (that isn't close).........................pob 1433 is busy, hung or dead....................................20915-1433 |
#19
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What Is Soyuz Using For Comm These Days?
Eric Chomko wrote:
On May 21, 7:05 pm, (Scott Dorsey) wrote: Rick Jones wrote: I wonder how much of Iridium still works, or how many satellite ISP's there are around the globe and how well a "base station" moving across/below them at 17000 MPH would work...assuming the base station kept a dish pointing at one or another of the ISP's satellites in GEO. Terrestar perhaps if it manages to launch? (although that would be NA only I guess) All of Iridium works. The whole constellation isn't up there, but you can pick up the phone anywhere in the world and get a call through. Iridium is pretty heavily used. Then why is Motorola broke? They bet the farm on Iridium and lost. Surely it isn't making anywhere near the money that cellular is making. Huh? Last time I checked Motorola had more than 2 billion dollars cash and cash equivalents. That's hardly "broke". They're into all sorts of things. As for Iridium, it's a privately held company so financials are not readily available--they're talking about launching another constellation so one presumes they're making money. However you're correct that they likely aren't making as much as cellular simply because running the whole constellation at saturation would be unlikely to be able handle even a tiny fraction of the call volume of the cellular system. There are actually a lot of satellite phone services and ISPs around the globe, but most of them are using satellites that target only a very small area. Iridium works anywhere, and it's a hell of a lot cheaper than INMARSAT. Why hasn't it replaced cellular service then? Surely satellite phones are better technology than is cellular. If sat phones are so cheap then why do I and millions of others still have cellular phones? In what way is satellite "better"? The only real advantages are that relatively limited terrestrial infrastructure is needed and it works just about anywhere that has a clear view of the sky. Call volume is going to be limited by bandwidth--a satellite with x bandtwidth can carry about the same call volume as a single cell tower with the same bandwidth, but, since cell towers have a very limited line of sight compared to a satellite the cellular system by having multiple towers can service vastly higher call volume. This leaves totally aside the issue of transmitter power vs antenna size and receiver sensitivity. -- -- --John to email, dial "usenet" and validate (was jclarke at eye bee em dot net) |
#20
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What Is Soyuz Using For Comm These Days?
On Thu, 29 May 2008 20:55:54 -0400, in a place far, far away, "J.
Clarke" made the phosphor on my monitor glow in such a way as to indicate that: Eric Chomko wrote: On May 21, 7:05 pm, (Scott Dorsey) wrote: Rick Jones wrote: I wonder how much of Iridium still works, or how many satellite ISP's there are around the globe and how well a "base station" moving across/below them at 17000 MPH would work...assuming the base station kept a dish pointing at one or another of the ISP's satellites in GEO. Terrestar perhaps if it manages to launch? (although that would be NA only I guess) All of Iridium works. The whole constellation isn't up there, but you can pick up the phone anywhere in the world and get a call through. Iridium is pretty heavily used. Then why is Motorola broke? They bet the farm on Iridium and lost. Surely it isn't making anywhere near the money that cellular is making. Huh? Last time I checked Motorola had more than 2 billion dollars cash and cash equivalents. That's hardly "broke". Don't mind Eric. He's the village idiot here. |
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