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Teledesic Comes Down to Earth
hibachi writes "Teledesic, the ambitious plan to build a constellation of low-earth orbiting satellites for global broadband services, has died on the assembly room floor. According to this press release, "the company does not believe that it is prudent, purely on speculation, to continue the substantial capital expenditures required to construct and launch the satellites consistent with the timing required to meet FCC and ITU regulatory milestones." Brainchild of Bill Gates and Craig McCaw, Teledesic held the promise of globally ubiquitous high speed Internet. It seems Teledesic's plans grew less ambitious over the years until finally the painful lessons of Iridium, and the current telecom climate, drove the last nails in its coffin. I am sad to see this happen."
Ah-ha!
http://angelhalo.com/
Kudos to the Wayback Machine for digging up the parent company's url!
Slashdot: rejecting tech news in favor of rubber band guns since 1997.
...to have something better than ISDN in my house here in Japan. At least its better than dialup where I paid $300 a month.
Apparently, this country needs to learn what does "national coverage" mean, and that linking two islands with 45mbit link and selling it to 35000 dsl, isdn, and dialup customers is not exactly the correct way of doing things.
Oh, and no signs of current-gen satellite internet in Japan either. DirectPC Japan sells "only to enterprises" with $2000-some for setup and after that billed PER MEGABYTE downloaded.
The Helios project will provide the same functionality, but with cheaper maintenance and launch costs. It is a solar-cell powered flying wing that will soar at about 60000 feet or so, with 200 pounds of payload. It may very well be the specific reason they pulled the plug on Teledisc, since they realize that most satelites will be obsoleted too soon for them to proceed with the project.
Stop the brainwash
Ever see an Iridium Flare?
Satellite broadband for the masses won't work. Period.
Here's the math to back that up.
Assume a bird at LEO - about 100 miles up, serving about a 500 mile footprint.
Assume said bird is running a 1 GHz wide communications channel (not a 1 GHz center frequency, 1 GHz bandwidth. That puts the center freq around 10 GHz at least, where there are very large space losses - just getting your signal down costs you a lot of signal).
Assume the protocol used by the bird gets about 4 bits per second per Hz (That's a pretty high value - the signal to noise ratio will have to be VERY low for this to work.)
Assume an overhead of 2 bits per byte transmitted. This includes all protocol below TCP/IP, error correction, collisions, retransmits, etc.
OK, given those numbers, you get about 400 Mbytes/sec downlink throughput.
Assume you want to supply everyone with DSL equivelent speeds - 40 kByte/sec.
400 Mbyte/sec divided by 40 kByte/sec = 100 thousand users per bird.
100 thousand users per 500 * pi miles = 64 users/square mile. Anyplace the user density is higher than that would swamp the system.
And remember, I've been using very LARGE (i.e. very favorable to satellite downlink) numbers.
Satellite is GREAT for wide-open, low population density areas. The problem then becomes you cannot get enough people to pay for the birds.
In high density areas, land based wireless and wireline are MUCH more cost effective. In less populated areas, ideas like the solar aircraft are more feasible than satellites. In REALLY unpopulated areas, there just ISN'T a technology that can do the job without some sort of subsidy.
www.eFax.com are spammers
the specs probably changed considerably from when i was doing this, but at that time, they were considering a network of 840 satellites! in some areas of the world you had maybe 10 or 20 satellites visible at once. if this thing had ever got off the ground, you'd have had some pretty spectacular displays around dawn and dusk.
what an amazing waste of money. personally i think that high altitude balloons sound like an excellent idea as a cheap alternative to behemoths like teledesic.