From: szabo@techbook.com (Nick Szabo)
Subject: PHONE CELL SATELLITES
Summary: Iridium, Globalstar out to change the space biz
Organization: TECHbooks --- Public Access UNIX --- (503) 220-0636
Date: Sun, 13 Sep 1992 06:30:15 GMT


PHONE CELL SATELLITES

Current cellular phones use a network of thousands of ground-based
towers each projecting a radio "cell" a few miles across.  Service is 
largely limited to cities in developed countries.  

Phone cells can greatly expand this service, while developing the
critical technology of miniature spacecraft components for the 21st
century.  The biggest markets are travellers and wealthy third worlders, 
who number 10's of millions despite being a small % of the total -- in 
Russia, India, China, Brazil, Mexico, Iran, Indonesia, Thailand, Turkey,
Eastern Europe, etc. that have no cellular service.  Cellsats can also 
usefully serve international air and ocean lines.   At least initially,
it won't compete with existing cellular service.  The market is 
universally (well, globally :-) available cellular service, at a higher 
cost.  How much higher depending on how many people sign on...the old 
chicken & egg story.  If everybody signed on, it would actually be much 
cheaper than the current local cell system, but these companies do not
count on that to happen initially; the systems can pay for themselves
by opening new niches.

The cost of the most publicized system, Iridium, is projected at 
$3 billion.  If one out of every five thousand people on our 
planet make $300 worth of phone calls a year for ten years, the 
system pays for itself.  Initially this would be mostly business, 
not personal use (as was the case for city cellular when
it started out).  For this market the price will be about twice as 
high as the current city cellular.  If the market expands well beyond 
1/5,000 of the world population, the price can go below that of current
urban markets, supplanting the thousands of towers with a more efficient
set of radio cells projected from space.   Concievably, with
an expanded set of satellites the price of cellular service could drop 
well below the price of current international long distance, replacing 
GEO satcoms altogether for this $10 billion/year market.  Initially, the
technology will be quite properly marketed at the 90% of the 
Earth's surface currently without cellular service.

IRIDIUM

Here are the Iridium specs.  Note that the constellation has
been redesigned for larger satellite and cell size, reducing
the number of satellites from 77 to 66:

satellite: 386 kg    
user handset: 3 lbs
voice,data,fax
digital & encryptable
global digital switch network
markets:
- general aviation and business aircraft
- maritime communications
- rural, Eastern Europe & Third World locations
$3/minute
- 1/2 to local providers
- 1/2 to Iridium members
370 mi. dia. cell * 37 * 11 * 7 (100K mi.^2)
66*4 cross-link antenae, each 20 Ghz
adjacent planes move in opposite directions	

Some tasks the Iridium people are working on:

* Building the satellites.  Since the scale is small, new technology
can be incorporated and tested with small risk.  Thus, there is
no need to stick with old electronic technology used in the larger 
GEO satcoms.  Lockheed will be in charge of developing the satellite
bus and choosing the launcher.  Motorola will develop the communications
payload and make and market the cellular phones.

* Choosing a launcher capable of boosting test and replacement 
satellites into their unique orbits for less than $10 million,
as well as a launcher for the main satellites, from one to seven
at a time, for less than $8 million apiece.  Currently Pegasus 
costs $10 million and fits the first bill, although with only one 
good launch under its belt it needs to prove its reliability. 
Delta or Atlas launching Iridium in groups of 6 could fit the
second bill, and a rumored Russian competitor to Pegasus might
be able to launch singlets for less than $8 million.  OSC needs 
to finish the Pegasus' hydrazine stage to improve the orbital 
insertion accuracy.  The development of Pegasus' low entry-level-cost 
capability was a main driver behind the inspiration and genesis of 
Iridium and several other emerging small satellite industries.

* The Iridium Consortium must obtain a set of frequencies in all 
the countries in which it wants to market its service.  Phone
cell satellites have obtained frequency from WARC and now each
proposal must compete at national government levels.

* New members must be added to the Iridium consortium; Motorola and
Lockheed probably won't pay all the $3 billion on their own.
The finance folks are busy talking to people like AT&T, NTT,
and dozens of other deep pockets.  Whoever puts in the most money
could very well gain control over the world's cellular phone 
industry.

GLOBALSTAR 

This information is from Klein Gilhousen of Quallcomm, Inc., which is
teamed with Loral and several European companies on Globalstar:

There will be 24 satellites in LEO (750 nm) in the initial deployment
with coverage optimized for the U.S.  Later, when international agreements
are in place, the constellation will be expanded to 48 satellites, providing
global coverage and improved coverage and capacity over the U.S.  

The system uses NO intersatellite relays.  (I believe that these relays
are a prime cost driver of the Motorola approach and that they would
solve a non-existent problem.  The problem is to connect mobile users
into the network.  Period.  Global routing of phone calls is something
that we already have.)  By virtue of have no crosslinks, the satellite
is significantly smaller and cheaper than the Iridium system.

Total launch mass of one satellite is 262 kg.  Eight satellites would be
stacked and launched at once by a Delta, Ariane, or other standard 
launch vehicle.

Airtime charges are projected to be in the same range as cellular
service.  According to the filing, initially, the airtime would be 
$0.31/minute with a monthly access fee of about $24.  Later on, charges 
would fall to about $0.22/minute.  

The mobile phones will be based on CDMA digital cellular phones with
RF adaptors to make them work in the L and S bands of the satellite
system.  Thus, the cost would be that of a CDMA cellular phone, plus 
maybe 10-20 percent for the adaptor.  

The system would offer call capacity comparable to that of the Iridium 
system's satellite network with many fewer and less costly satellites through
the use of the CDMA technology.  Because a much smaller investment is
required, the service cost will be correspondingly smaller.  

CONCLUSION

Thinking small -- thinking at the optimum economical scale of 
technology, instead of the idealistic scale of technology -- 
is one of the major paradigm advances of phone cell satellites.  
The Iridium and Globalstar breakthrough is a good example of why 
industry is needed to set the standards for space technology, 
instead of government dictating to industry.  Private industry
is far more in tune both with the advance of technology and
the needs of people.  Government civilian programs have practically 
ignored -- spent less than 1% of their budgets on -- the technology 
needed for this lucrative market.  Private industry is putting up 
its own money to fill this gap.


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